Yang Yang

Professor Yongmin Zhang

Chong Wei

Jing Li

Wenji Sun

Silver ion chromatography for peak resolution enhancement: Application to the preparative separation of two sesquiterpenes using online heart-cutting LC-LC technique

Keywords: Positional isomers, Argentation, Peak resolution enhancement, Heart-cutting LC-LC, Preparative separation, Natural product

Silver ion chromatography, utilizing columns packed with silver ions bonded to silica gel, has proved to be an invaluable technique for the analysis of some positional isomers. In this work, silver ion chromatography by combination with online heart-cutting LC-LC technique for the preparative separation of two sesquiterpenes positional isomers from a natural product was investigated. On the basis of the evaluation that silver ion content impacts on the separation, the laboratory-made silver ion columns, utilizing silica gel impregnated with 15% silver nitrate as column packing materials, were used for peak resolution improvement of these two isomers and the preparative separation of them in heart-cutting LC-LC. The relationship among the maximal sample load, flow rate and peak resolution in the silver ion column were optimized, and the performance of the silver ion column was compared with conventional C18 column and silica gel column. Based on the developed chromatographic conditions, online heart-cutting LC-LC chromatographic separation system in combination with a silica gel column and a silver ion column that was applied to preparative separation of these two isomers from a traditional Chinese medicine, Inula racemosa Hook.f., was established. The results showed that the online heart-cutting LC-LC technique by combination of a silica gel column and a silver ion column for the preparative separation of these two positional isomers from this natural plant was superior to the preparative separation performed on a single-column system with C18 column or silica gel column.

Introduction

Silver ion chromatography, utilizing columns packed with silver ions bonded to a silica gel or similar substrate, has proved to be an invaluable technique for the analysis of complex triacylglycerol mixtures, fatty acids, lipids and some positional isomers [START_REF] Dobson | Silver ion chromatography of lipids and fatty acids[END_REF][START_REF] Adlof | Analysis of triacylglycerol and fatty acid isomers by low-temperature silver-ion high performance liquid chromatography with acetonitrile in hexane as solvent: Limitations of the methodology[END_REF][START_REF] Daramwar | Preparative separation of α-and β-santalenes and (Z)-α-and (Z)-β-santalols using silver nitrate-impregnated silica gel medium pressure liquid chromatography and analysis of sandalwood oil[END_REF][START_REF] Adlof | Analysis of triacylglycerol positional isomers by silver ion high performance liquid chromatography[END_REF]. This application based on the mechanism that the different number, or/and geometrical configuration, or/and position of unsaturated C-C bonds provide the different amount of π donors. Since silver ions act as π acceptors while unsaturated C-C bonds act as π donors, causing molecules that contain fewer π donors or do not contain π donors to be eluted firstly on silver ion chromatography [START_REF] Guha | Charge-transfer complexes of metals in the chromatographic separation of organic compounds[END_REF].

Although silver ion chromatography by a single-column system is inexpensive and easy to operate for the trace separation and determination of active ingredients, or preparative separation compounds from simple sample on small-scale [START_REF] Adlof | Separation of conjugated linoleic acid methyl esters by silver-ion high performance liquid chromatography in semi-preparative mode[END_REF], it still restricts to the large-scale preparative separation of compounds from complex natural products. Due to adsorption of excessive impurities, the action of silver ions becomes worse, causing the decrease of column separation efficiency, even resulting in bleeding of silver ions and affecting the UV detector. In addition, a single-column system sometimes has limited sample capacity and poor relative peak separation [START_REF] Stoll | Comparison of the practical resolving power of one-and two-dimensional high-performance liquid chromatography analysis of metabolomic samples[END_REF].

Notably, heart-cutting two-dimensional liquid chromatography (LC-LC) offers the probability to improve these drawbacks based on a tandem combination of two independent liquid phase separation systems [START_REF] Xie | Preparative High Performance Liquid Chromatography-based Multidimensional Chromatography and Its Application in Traditional Chinese Medicine[END_REF][START_REF] Pursch | Loop-based multiple heart-cutting two-dimensional liquid chromatography for target analysis in complex matrices[END_REF][START_REF] Wang | The use of online heart-cutting high-performa nce liquid chromatography coupled with linear ion trap mass spectrometry in the identification of impurities in vidarabine monophosphate[END_REF][START_REF] De Souza | Heart-cutting two-dimensional (size exclusion × reversed phase) liquid chromatography-mass spectrometry analysis of flavonol glycosides from leaves of Maytenus ilicifolia[END_REF].

Inula racemosa Hook.f., a medicinal plant, is widely distributed in Europe, Asia and Africa [12]. Its root as a traditional medicine has been most frequently applied for issues related to peptic disorders, phlegm, detumescence, inflammatory and vermifuge [START_REF] Song | Dictionary of Modern Chinese Materia Medica[END_REF]. Alantolactone (AL) and isoalantolactone (IS) (Figure .1) are two sesquiterpenes positional isomers and have abundant content in this medicinal plant. Previous studies suggested that they show many biological activities [START_REF] Rasul | Targeting apoptosis pathways in cancer with alantolactone and isoalantolactone[END_REF][START_REF] Chun | Alantolactone suppresses inducible nitric oxide synthase and cyclooxygenase-2 expression by down-regulating NF-κB, MAPK and AP-1 via the MyD88 signaling pathway in LPS-activated RAW 264.7 cells[END_REF][START_REF] Schmidt | Antitrypanosomal activity of helenalin and some structurally related sesquiterpene lactones[END_REF][START_REF] Lokhande | Antibacterial Activity of Isolated Constituents and Extract of Roots of Inula racemosa[END_REF][START_REF] Grimaud | Les Astéracées du Ladakh dans la médecine tibétaine[END_REF][START_REF] Qiu | Subinhibitory concentrations of farrerol reduce α-toxin expression in Staphylococcus aureus[END_REF][START_REF] Zhang | Inhibition of thioredoxin reductase by alantolactone prompts oxidative stress-mediated apoptosis of HeLa cells[END_REF][START_REF] Mi | Alantolactone induces cell 13 apoptosis partially through down-regulation of testes-specific protease 50 expression[END_REF][START_REF] Yao | Alantolactone induces G1 phase arrest and apoptosis of multiple myeloma cells and overcomes bortezomib resistance[END_REF][START_REF] Cai | Growth Inhibition Effects of Isoalantolactone on K562/A02 Cells: Caspase-dependent Apoptotic Pathways, S Phase Arrest, and Downregulation of Bcr/Abl[END_REF][START_REF] Seo | Isoalantolactone from Inula helenium Caused Nrf2-Mediated Induction of Detoxifying Enzymes[END_REF][START_REF] Seo | Nrf2-mediated induction of detoxifying enzymes by alantolactone present in Inula helenium[END_REF], especially in killing of cancer cells. In addition, researchers also have examined the relationship between their structural modifications and biological activities [START_REF] Cantrell | Structure -Activity Relationship Studies on Derivatives of Eudesmanolides from Inula helenium as Toxicants against Aedes aegypti Larvae and Adults[END_REF][START_REF] Klochkov | Modification of alantolactones by natural alkaloids[END_REF][START_REF] Guo | Structural modification of isoalantolactone and biological activity against the hepatoma cell lines[END_REF]. These studies suggested that AL and IS may be good potential lead compounds for future anticancer agent development or act as chemical templates for the design, synthesis, and semisynthesis of new substances. Nevertheless, further studies are required in preclinical and clinical applications and to explain their potential role. For these studies, it certainly will need a large number of materials. In the current ways, acquisition of AL and IS from natural plants is a short-cut. Therefore, a robust method for the preparative separation of AL and IS from this medicinal plant may be necessary. Unfortunately, the structural similarity of AL and IS increases the preparative separation difficulty of them from this natural plant. Although the traditional separation methods used in the trace separation and determination of these two compounds have been performed with capillary electrophoresis (CE) [START_REF] Wang | Separation and determination of alantolactone and isoalantolactone in traditional Chinese herbs by capillary electrophoresis[END_REF], gas chromatography (GC) [START_REF] Zhang | Determination of alantolactone and isoalantolactone Inula herbs by gas chromatography[END_REF] and RP-HPLC [START_REF] Guo | Simultaneous determination of sesquiterpene lactones isoalantolactone and alantolactone isomers in rat plasma by liquid chromatography with tandem mass spectrometry: Application to a pharmacokinetic study[END_REF][START_REF] Sharma | Separation of isoalantolactone and alantolactone in Inula racemose root by RP-HPLC[END_REF], when these methods are used to isolate AL and IS from Inula racemosa Hook.f. on a larger scale, it becomes difficult due to the limitation of the resolution between their peaks. Hence, the establishment of an effective method for increase of the peak resolution and its application to their preparative separation from this plant becomes a key problem. Since AL and IS constitute a pair of positional isomers related to C=C bond, silver ion chromatography provides the probability to improve the separation of them (Figure .1). Therefore, the aim of this study was to improve the separation of these two isomers by silver ion chromatography in preparative scale and obtain them from a crude extract of Inula racemosa Hook.f. by preparative separation with silver ion chromatography technique in combination with online heart-cutting LC-LC technique.

Experimental

Materials and reagents

The dried roots of Inula racemosa Hook.f. were purchased from Bai Ding (Tibet, China).

Alantolactone and isoalantolactone were purchased from National Institute of Food and Drug Control for the quantification and qualitative study (Beijing, China). Silver nitrate was of chemical grade (Zhengzhou Kaidi Chemical Products Co., Ltd, Henan, China). Silica gel (5 ~ 10 μm particles and 10 ~ 40 μm particles) was purchased from Qingdao Yida Silica Reagent Factory (Fujian, China).

Ethyl acetate, n-hexane, 95% ethanol and acetonitrile reagents were of analytical grade and purchased from Xi'an Chemical Reagent Factory (Shaanxi, China).

Sample preparation

The dried roots of Inula racemosa Hook.f. were pulverized and sieved through a screen (100 ~ 200 mesh). 100 g of this powder was extracted with 1000 ml of 95% ethanol solution by ultrasonic treatment for 30 min at 45 °C and 100 kHz/450 W (Bandelin Sonorex, Germany) [START_REF] Trendafilova | Ultrasound-assisted extraction of alantolactone and isoalantolactone from Inula helenium roots[END_REF] and repeated three times. The extracts were concentrated on a rotavapor at 45 °C (REC32E, Shanghai Yarong Instrument, China). The residues were dissolved in n-hexane/ethyl acetate (100 mL: 70/30, v/v) solution to get sample solutions for the preparative separation, and the contents of AL and IS in this sample solution were 25.62 mg/mL and 31.32 mg/mL, respectively.

The stock solution for the analysis of AL and IS was prepared by dissolving AL and IS into n-hexane/ethyl acetate (70/30, v/v) and mixing at concentration containing AL of 25.86 mg/mL and IS of 30.26 mg/mL.

Column packing

The laboratory-made silver ion column, utilizing silica gel impregnated with silver nitrate as column packing materials, was prepared for the preparative separation in heart-cutting LC-LC.

The silica gel impregnated with silver nitrate was prepared by the method reported previously with slightly modification [START_REF] Li | Modified and convenient preparation of silica impregnated with silver nitrate and its application to the separation of steroids and triterpenes[END_REF] (Figure .2). To avoid waste and the risk of blindness, the silver ion content in silica gel impregnated with silver nitrate for the impact on the separation of these two isomers was first observed on silver ion TLC plate [START_REF] Li | Modified and convenient preparation of silica impregnated with silver nitrate and its application to the separation of steroids and triterpenes[END_REF]. Then the sliver ion columns (Stainless steel tube, Jiangsu Hanbang Co. Ltd., China) were slurry packed with ethyl acetate using a CST chromatographic column packing machine (KeSheng Experimental Equipment Co., Ltd., Suzhou, China) according to the operating instructions, and the performance of the prepared silver ion column for the preparative separation of these two isomers was investigated and compared with C18 column on preparative HPLC instrument (Two Alltech-627 high-pressure pumps equipped with a Model-500 UV-VIS detector, Alltech, USA).

Connections of the heart-cutting LC-LC system

The connections of the heart-cutting LC-LC system are illustrated in Figure .3. The column temperatures were controlled at 30 ℃ using an independent QT-330 chromatographic column thermostat (Henan Jiuhegongchuang co., Ltd., China). Two NP7000-C high-pressure pumps equipped with a NU3010-C UV-VIS detector (Jiangsu Hanbang Technology Co., Ltd., Jiangsu, China) were involved in the first dimension, and the UV detector was set at 260 nm. The system control and data collection were carried out using an EasyChrom-1000 chromatographic workstation. A silica gel column (22 mm i.d. × 250 mm, 5 μm, Grace, USA) as a preparative column was used for the first-dimension separation, while a 22 mm i.d. × 20 mm silica gel column as pre-column was equipped between the sample loop and the preparative column. In addition, two Alltech-627 high-pressure pumps equipped with a Model-500 UV-VIS detector (Alltech, USA) were used in the second dimension, and the UV detector was set at 260 nm. The system control and data acquisition were performed by using an AllChrom Plus server workstation. The second-dimension separation was performed on a laboratory-made sliver ion column (22 mm i.d. × 250 mm).

Procedure for preparative separation

Quantitative HPLC analysis

The crude Inula racemosa Hook.f. extract and the prepared compounds were analyzed by a commercially available sliver ion column (4.6 mm i.d. × 250 mm, ChromSpher Lipids CP28313, Varian, USA) in the analytical HPLC instrument (Waters 2695 HPLC system equipped with a Waters 2487 UV-VIS detector controlled through an Empower chromatographic workstation, Waters, USA). The concentration range of calibration solutions obtained by diluting the stock solutions at the range of 5172.0-323.25 μg/mL for AL and 6052.0-378.25 μg/mL for IS.

Chromatographic separation was performed using an isocratic elution at a flow rate of 1.0 mL/min with mobile phase 75/25 (n-hexane/ethyl acetate). The column temperature was controlled at 30 °C, and the effluents were monitored at 260 nm by a UV detector.

Results and discussion

Silver ion content in the improvement of separation

For the preparative separation of AL and IS, the goal in the present study was to obtain them with high efficiency. Since low sample load reduces the efficiency in preparative separation of AL and IS, we were concerned about the increase of the maximal sample load. It is well known that the resolution has great influence on the maximal sample load, as well as run times, equilibration times and solvent consumption. With increase of sample load, the resolution decreases [START_REF] Destefano | Preparative high-performance liquid chromatography[END_REF]. The decreased resolution limits the increase of the maximal sample load and throughput per unit time.

Therefore, the enhancement of the resolution between AL and IS may improve the maximal sample load.

The amount of silver ion in the silica gel impregnated with silver nitrate is vital for the improvement of the resolution. Therefore, the investigation on the content of silver nitrate may be necessary. TLC technique in the evaluation of the effect of silver ion content is easy and convenient in this study. In the TLC separation, the developing solvent was composed of n-hexane/ethyl acetate (80/20). The TLC plates were sprayed with an ethanol solution containing 10% sulfuric acid and then heated in an IR drier until obvious colour appeared. As shown in Fig. 4, AL and IS could not be isolated completely on the TLC plates when no silver nitrate added into silica gel (Figure. ). Since the level of silver nitrate impregnation recommended has varied from 0.5-40% [START_REF] Morris | Separations of lipids by silver ion chromatography[END_REF] and the case where we have found 10% of impregnation is more effective for separations of isomers in column separation [START_REF] Cert | New method of stationary phase preparation for silver ion column chromatography: : Application to the isolation of steroidal hydrocarbons in vegetable oils[END_REF], 6%, 10% and 15% silver nitrate to improve the separation were investigated in the present study. From the obtained thin-layer chromatograms impregnated with 15% silver nitrate as column packing materials was prepared in the following study. Whether more than 15% silver nitrate is more effective in preparative separation of these two isomers needs to be explored.

Sliver ion column for the separation of two sesquiterpenes positional isomers

Even though these two positional isomers achieved good separation on silver ion TLC plates with 15% of impregnation, whether the preparative separation in HPLC, utilizing silver ion column packed with this impregnation (15% silver nitrate), could acquire improvement was unknown. Based on the TLC analysis, the investigation was first performed on a single laboratory-made 4.6 mm i.d. × 250 mm sliver ion column with mobile phase 80/20

(n-hexane/ethyl acetate, v/v) at the flow rate of 1 mL/min, where it obtained a good peak resolution, and a satisfactory peak shape and separation times within 20 μL of the stock solution (Figure .5a), whereas peak resolution decreased when the sample load increased to 80 μL of the stock solution (Figure .5b). Since the mobile phase with n-hexane/ethyl acetate (80/20, v/v) shortened their separation times and reduction of ethyl acetate concentration (Such as reduction of 5% ethyl acetate) in mobile phase has a great influence on the retention times, the optimization of the mobile phase composition for the increase of sample load was not carried out. Furthermore, considering that reduction of the flow rate may improve the peak resolution and then increase the sample load [START_REF] Wang | Theory-guided efficient strategy to maximize speed and resolution in rapid gradient LC-MS/MS bioanalysis[END_REF], the mobile phase 80/20 (n-hexane/ethyl acetate, v/v) at the flow rate of 0.8 mL/min and 0.6 mL/min were evaluated in the following experiment, respectively. When the flow rate decreased to 0.8 mL/min, a complete resolution could be obtained within 180 μL of the stock solution (Figure .6), while the retention times of these two isomers slightly delayed but there was no obvious changes in the peak shape. When the sample load continued increasing, bad resolution appeared (Figure .6). In a view of this, the flow rate reduced to 0.6 mL/min, in which the maximal sample load increased to 480 μL of the stock solution with a complete resolution (Figure.5c and Figure .6). However, the peaks seem to be flat and trailing, and the retention times delayed markedly (Figure .5c). The reason may be the decrease in the elution strength of solvent at the low flow rate. Therefore, the mobile phase was optimized for n-hexane/ethyl acetate (75/25), which reduced peaks trailing and retention times (Figure .5d) and given a complete resolution. Fig. 6 shows the relationship among the resolution, sample load and flow rate. With the increase of sample load, the peak resolution decreased. The increased flow rate also reduced the peak resolution and leaded to the decrease of the peak height. Although the decrease of the flow rate made peak width increase slightly, it obtains a good resolution (≥ 1.5) with the increase of sample load. When the sample volume increased to 480 μL of the stock solution, the resolution between the AL and IS nearly equals to 1.5 at the flow rate of 0.6 mL/min, so the sample load didn't increase any more.

In order to validate the recovery and repeatability under the developed conditions using the prepared silver column, 480 μL of the stock solution was separated on the 4.6 mm i.d. × 250 mm column with n-hexane/ethyl acetate (75/25) at the flow rate of 0.6 mL/min. By six replicate experiments, the recovery of AL was 95.3% with RSD of 1.3% and that of IS was 95.1% with RSD of 1.6%, while the repeatability was determined with the values of RSD of 1.09% and 1.23%.

The results showed a satisfactory recovery and repeatability.

Conventional separation methods

C18 and silica gel packing materials are commonly used for preparative separation. Evidently, compared with silica gel, silica gel impregnated with silver nitrate achieved good separation with the increase of sample load (Figure .4). To further evaluate the performance of the laboratory-made silver ion column (4.6 mm i.d. × 250 mm), a same size C18 column (4.6 mm i.d. × 250 mm) for preparative separation of AL and IS was compared with the silver ion column (Chromatographic conditions were presented in supplementary material). Although a satisfactory separation achieved on C18 column using a higher concentration of water in the mobile phase, it sacrificed a lot of time and still had limited sample treatment capacity because of the limitation of the peak resolution.

However, the silver ion column reduced the retention times and increased the maximal sample load with good resolution, compared to C18 column (Table . 1 and Figure .7).

Application of heart-cutting LC-LC system in the preparative separation

The online heart-cutting LC-LC technique was applied to the preparative separation of these two positional isomers from this natural plant. Although AL and IS could not be separated completely with silica gel materials, the fraction of AL and IS achieved good separation (Figure .4-1 and Figure .8a). Therefore, a silica gel columns was equipped on the first-dimension separation to isolate the fraction of AL and IS from the crude extract, while a laboratory-made 22 mm i.d. × 250 mm sliver ion column was selected for the second-dimension separation to further separate AL and IS. The elution conditions both in the first dimension and the second dimension were developed based on the above analysis. The maximal sample load and the flow rate for the selected silver ion column in LC-LC separation were estimated by applying the linear amplification analysis (About 10.9 mL of the stock solution and flow rate of 14 ml/min) [START_REF] Zhu | Linear amplification -effective technology of preparation liquid chromatography[END_REF], and then the diameter of the silica gel column used in first-dimension separation was chosen based on the requirement for making full use of the selected silver ion column in the advantage of the high sample load. For this reason, if 11 mL of the crude extract solution can be treated by silica gel column equipped on the first dimension, the sample load amount loaded on the selected silver ion column transferred from the first dimension may be close to its maximal sample load in LC-LC preparative separation. Therefore, two silica gel columns, with different diameters (10 mm i.d. × 250 mm, 22 mm i.d. × 250 mm), were tested respectively. The results showed that the 22 mm i.d. × 250 mm column was superior to another one, in which it could treat 10 mL of the crude extract solution with n-hexane/ethyl acetate (85/15, v/v) at the flow of 12 mL/ min (Figure .8b-d). Hence, a 22 mm i.d. × 250 mm silica gel column with n-hexane/ethyl acetate (85/15, v/v) as eluent at the flow of 12 mL/ min was used for the first-dimension separation.

Although 10 mL of the crude extract solution could be treated in the first-dimension separation (Figure .9a), a bad separation appeared in the second-dimension separation with n-hexane/ethyl acetate (75/25, v/v) at the flow of 14 mL/ min. However, when the flow rate in the second-dimension separation decreased to 10 mL/min, the peaks of these two isomers obtained a baseline separation (Figure .9b). In addition, to maintain the column separation performance per unit time, the columns restored by elution using 100% ethyl acetate at the end of separation each time. Using multicycle and consecutive separation, 2.3 g of AL with a purity of 97.8% and 2.8 g of IS with a purity of 98.8% were obtained from of the crude extract within 8.5 hours. In an LC-LC separation model, the preparative separation achieved high-efficiency compared with conventional methods.

Moreover, the crystals obtained from 90% ethanol were analysed by X-ray diffraction. Full crystallographic details for the compounds reported in this paper were deposited in the Cambridge Crystallographic Data Centre as Supplementary Publication No. CCDC 1438651 for AL (1) [40] and No. CCDC 1438652 for IS (2) [41]. Copies of these data can be obtained upon application to the CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK [http://www.ccdc.cam.ac.uk].

Conclusion

Silver ion chromatography was demonstrated to be an effective technique for improvement of the separation of AL and IS in preparative scale. Online heart-cutting LC-LC technique by combination of the silica gel column and silver ion column was successfully applied to preparative separation of AL and IS from a crude extract of Inula racemosa Hook.f. This study offers a rapid and effective approach for the preparative separation of these two positional isomers from natural

First

  -dimension unit separation-N-hexane (A)/ethyl acetate (B) (v/v) were employed as the mobile phase. 10 mL of the sample solution was injected into a 20 mL sample loop while valve A was set at position B. Then the elution program was carried out by the EasyChrom-1000 chromatographic workstation: 0-15 min (Valve A at position A; Flow rate, 12 mL/min; 85% A/15% B; When the peak of the fraction containing AL and IS started to emerge, valve B and valve A were all switched to position B: the fraction containing AL and IS was cut and transferred onto the silver ion column via the automatic FC-AS-312 component collector), and 15.1-25 min (Valve A at position B; flow rate, 15 mL/min; 0% A/100% B) and 25.1-30 min (Valve A at position B; flow rate, 15 mL/min; 85% A/15% B). Second-dimension unit separation-When all of the fraction containing AL and IS from the first-dimension column had been completely transferred onto the second-dimension column, the following elution program was run with a mobile phase composition of (A) n-hexane/(B) ethyl acetate: 0-22 min (Valve B at position A; Flow rate, 10 mL/min; 75% A/25% B; AL and IS were automatically collected by the component collector on the second-dimension unit), 22.1-25 min (Valve B at position B; Flow rate, 15 mL/min; 0% A/100% B) and 27.1-32 min (Valve B at position B; Flow rate, 15 mL min -1 ; 75% A/25% B).

  Figure.4-4 -Figure.4-9). Since the level of silver nitrate impregnation recommended has varied

(

  Figure.4), with the increase of the silver nitrate content, the amount of sample load increased with complete separation. Since 15% silver nitrate facilitated the isolation more effectively than other ratios with the increase of sample load (Figure.4-3 -Figure.4-9), silica gel (5 ~ 10 μm particles)

Figure. 1

 1 Figure.1 Schematic illustration of sliver ion chromatography for the separation of alantolactone (AL) and

Figure. 2 .

 2 Figure.2. Schematic illustration of the preparation of silver ion columns packed with silica gel impregnated with

Figure. 3 .

 3 Figure.3. Schematic illustration of the instrumental configurations used for online heart-cutting LC-LC preparative

Figure. 4 .

 4 Figure.4. 0% (1, 3), 6% (4, 7), 10% (5, 8) and 15% (6, 9) silver nitrate as additives: (3-6), 10 μL of the stock solution was separated on silver ion TLC plates; (7-9), 20 μL of the stock solution was separated on silver ion TLC plates; (1), the crude extract was separated on silica gel TLC plate; (2), the crude extract was separated on silver

Figure. 5 .

 5 Figure.5. (1) AL and (2) IS. (a) 20 μL of the stock solution was separated with mobile phase 80/20 (v/v) for n-hexane/ethyl acetate at the flow of 1 mL/min; (b) 80 μL of the stock solution was separated with mobile phase 80/20 (v/v) for n-hexane/ethyl acetate at the flow of 1 mL/min; (c) 480 μL of the stock solution was separated with mobile phase 80/20 (v/v) for n-hexane/ethyl acetate at the flow of 0.6 mL/min; (d) 480 μL of the stock solution was separated with mobile phase 75/25 (v/v) for n-hexane/ethyl acetate at the flow of 0.6 mL/min. Detection: UV

Figure. 6 .

 6 Figure. 6. The relationship among the resolution, sample load and flow rate. Column: Laboratory-made 4.6 mm i.d.

Figure. 7 .

 7 Figure.7. (1) AL and (2) IS. Chromatogram: Separation of AL and IS with mobile phase 65:35 (v/v) for

Figure. 8 .

 8 Figure.8. (a) 10 μL of the crude extract solution was separated on a 4.6 mm i.d. × 250 mm column with mobile phase 80/20 (v/v) for n-hexane/ethyl acetate at the flow of 1 mL/min. (b) 6 mL of the crude extract solution was

Figure. 9 .

 9 Figure.9. (1) AL and (2) IS. Chromatogram of online heart-cutting LC-LC separation: (a) the first-dimension

Acknowledgements

This work was financially supported by the Project of Natural Science Foundation of Shaanxi Province of China, One Hundred Person Expert Project of Shaanxi Province of China (2014JM4125).

product.


V Alérie-I Nés De La

Eléonore M Ounoud

BETWEEN D I SCOURSE AN D N ARRATI ON : H ow Can Strategy Be a Practice ?

The aim of this text is to explore the idea that strategic management research w ould profit from a practice-oriented approach, w here practice is defined as everyday situated embedded in local contextsactions performed by organizational members in order to make strategy. Draw ing on tw o empirical w orks, w e study tw o kinds of such practice: actions (as accounted for by the actors) and narrations (as structured by the narrators). In the first case, strategic discourse is contrasted to action and its tactics ; in the second, strategic discourse is contrasted to narratives. Their interpretation is aided and dramatically enriched by a contrast betw een strategy and tactic, as introduced by M ichel de Certeau. This contrast emphasizes the discursiveor paradigmaticnature of strategy opposed to the narrativeor syntagmaticnature of practice.

Towards a practice-oriented approach of strategy research

Even if organizational studies, especially critical studies, have adopted a skeptical stance tow ards strategists and their role in organizational life, strategy is a key issue for organizationsespecially for companies. Indeed, top executives and managers label "strategies" the narratives they continuously use in organizing. These strategies shape the lives of people and organizations in accordance to their ow n logic and requests.

Strategy is the yardstick by w hich the quality of individual and organizational effort is assessed. The "quest for strategy" has spread to every organization, follow ing the global managerialization of Western societies.

Thus, the issue of strategy calls for reflection w ithin the context of organizations for at least three reasons:

 the notion of strategy holds a commanding position in organizations,  "strategic principles" (planning, budgeting, positioning, etc.) have deeply infused

everyday social life,  the institutionalization of "strategy" through education, training and consultancy legitimates the present logic of domination in organizations (Knights & M organ 1991 ;Whittington 1993).

Since M intzberg's attempt to classify the schools of thought in "strategy" (M intzberg 1991), the field of "strategic management" appears to have taken a more reflexive turn.

M ore specifically, the contribution of the new institutionalism has lead t o a complex interw eaving of the social, political and economic dimensions in the study of strategy making. Gerry Johnson and Cliff Bow man as w ell as Richard Whittington, urge researchers in strategic management to engage in a drastic change of focus (Whittington 1996;[START_REF] Johnson | Strategy and everyday reality: the case f or the study of "micro-strategy[END_REF]. Such shift w ould consist in paying more attention to day-to-day routines rather than to "grand strategy" emphasized by decision-making studies, and in including political, cultural and interactional aspects of management into the picture. This so-called micro-strategizing perspective lays emphasis on local rather than universal aspects and is concerned w ith activities, processes and routines as signs of strategic practice. In such view , the making of strategy is embedded in everyday organizational routines, like the permanent appeal to consultants, the ongoing process of corporate planning and budgeting, the w riting of documents, the making of presentations (Whittington 1996).

This essay is grounded into tw o recent streams of investigation that, on the one hand, explore the discursive nature of strategy making and, on the other hand, try to account for the everyday individual actions and narrations that shape organizational life.

Exploring strategic discourses at the organizational level has been legitimized on the strategic management research agenda [START_REF] Barry | Strategy retold: tow ard a narrative view of strategic discourse[END_REF][START_REF] O'connor | Plotting the organization: the embedded narrative as a construct for studying change[END_REF].

Strategy formation has therefore been analyzed in terms of discourse formation, discourses that w ill possibly generate opposition and undergo successive modifications w ithin a given organizational context. For example, [START_REF] Carter | M anagerial meditations: an analysis of the discursive constitution of the strategy process[END_REF] have studied how it has become necessary for an English public utility to formulate explicit strategies w hen entering a new competitive environment: "Strategy formulation, therefore, became a Callonesque obligatory point of passage and w as constituted as being of such importance that it w as now one of the core responsibilities of senior management. " (Carter, M ueller & Clark, 2001 : 190) This strategy formulation underw ent different iterations, for example by turning from diversification-prone to diversification-adverse w hen facing internal resistance. In Carter et al.'s analysis, much emphasis is put on legitimacy as both a condition and an outcome of strategy formulation.

A contrasting view pleads for focusing more accurately on the activities of individuals in strategy-making [START_REF] Johnson | Strategy and everyday reality: the case f or the study of "micro-strategy[END_REF]. This so-called micro-strategy perspective implies conducting analysis across multiple levels: individual interactions, organizational dynamics and social contexts. Whittington narrow ed this research program even further by defining strategizing as the specific activity of a group of strategists (experts, consultants, top managers). N evertheless, in our view , studying behaviours and discourses at the individual level only is risky as it leads more frequently to reinforcing the production of hagiographic accounts than to providing a comprehensive understanding of strategy-making. The promotion of neo-Schumpeterian heroes in entrepreneurial strategies can thus be seen as a demiurgic drift in research accounts of management [START_REF] De | Apprentissages collectifs et structuration de la stratégie dans la jeune entreprise de haute technologie -Etude de cas et éléments de modélisation procédurale[END_REF].

This chapter is divided into three parts. In the first part, w e explain how researchers consider and use the notion of "strategy" in organizations through a brief overview of strategy literature. Building on Whittington's (1996) categorization of strategic research into four perspectivespolicy, planning, process and practicew e show how different perspectives conceive of strategy making. By choosing to conceptualize "strategy making" as a matter of telling, recounting and communicating w hich takes place in organizations, w e take up his proposal to develop a practiceoriented view of strategy-making.

In the second part, w e suggest the need to explore the notion of practice more systematically to define the possible links betw een practice and strategy. In order to do so, w e explore some concepts and approaches developed by M ichel de Certeau in his w ork The Practice of Everyday Life (1988). Draw ing on his unusual definitions of tactic and strategy that emphasize anti-discipline and resistance to domination, w e may better account for the underlying logic of domination hidden by the discourses of 'grand strategy' (Whittington 1993). M oreover, M ichel de Certeau constantly mirrors the relationship of w riting to reading to the relationship of production to consumption. In doing so, he suggests that discourses, like goods on a market, are produced by makers and imposed on consumers, thus strongly framing their potential meaning and use.

Building on this metaphor, strategy can be conceived as an ongoing creative process involving not only w hat strategists produceor w rite -(budgets, plans, strategies) but also the w ays the members of the organization consumeor readtheir productions.

Seen in this light, studying the practice of strategy implies giving more room to w hat middle managers and employees "make " or "do ", how they use and transform the grand discourse of strategy. This "poaching ability ", as de Certeau w ould have called it, relies on a multiplicity of intertw ined w ays of talking, doing and believing. Follow ing this line of reasoning, w e suggest that the change of focus from discourses of "grand strategy" to the minutiae of everyday practice necessarily leads to scrutinizing the differences betw een discourses and narratives.

In the last part of this article w e analyze strategy making as the intertw ining of strategic discourses and practice narratives, draw ing on tw o empirical studies of strategic practices [START_REF] De | Apprentissages collectifs et structuration de la stratégie dans la jeune entreprise de haute technologie -Etude de cas et éléments de modélisation procédurale[END_REF], 1999 ;[START_REF] Eléonore | L'inscription sociale des discours et des représentations stratégiques dans l'industrie de l'Environnement[END_REF], 2000). The first study is a fouryear idiographic research of a young high-tech firm. The narratives of several organizational members highlight the minutiae of strategy -in-the-making as w ell as the various tricks and poaching tactics that shape their practice. The second study illustrates the consumption of discourses produced by others (scientists, economists, politicians, ecologists) and the creation of narratives in an attempt to organize an emergent organizational field and to secure domination upon it.

Contrasting Theoretical Approaches to Strategy-M aking

In his textbook for managers provocatively entitled, What Is Strategy, and Does It M atter?, Whittington (1993) questions the basic assumptions of orthodox strategic perspectives that assume predictable environments, similar competitors and rational decisionmakers. H is exploration of the underlying assumptions held by different theoretical perspectives aimed at explaining how strategy develops, leads him to distinguish four basic approaches to strategy-making:

 "Classical" : the planning approach This perspective conceives strategy as a rational process of deliberate calculation and analysis, designed to maximize long-term advantage. If enough effort is made to gather the information needed and to apply appropriate techniques, both the outside w orld and the organization itself can be made predictable and plastic, shaped according to the careful plans of top managers.

 "Evolutionary": the efficiency-driven approach

In this perspective, the environment is considered to be often too unpredictable to anticipate its evolutions effectively. The dynamic, hostile and competitive nature of markets means that long-term survival cannot be planned for. Businesses are like the species of biological evolution. Competitive processes ruthlessly select out the fittest for survival, w hile the others are pow erless to change themselves quickly enough to escape extinction. It is the market, not managers w hich makes the important choices. A ll managers can do is ensure that they fit as efficiently as possible to the environmental demands of the day.

 "Processual": the craft-like approach A ccording to this perspective, people w ithin organizations are too different in their interests, limited in their understandings, w andering in their attention and careless in their actions to unite around and then carry out a perfectly calculated plan. A nyw ay, plans tend to be forgotten as circumstances change. In practice, strategy emerges more from a pragmatic process of learning and compromise than from a rational series of grand leaps forw ard. The selection processes of the market are actually rather lax: as noone is likely to know w hat the optimal strategy is, and no-one w ould stick to it anyw ay, failure to design and carry out the perfect strategic plan is not going to entail any fatal competitive disadvantage.

 "Systemic": the socially-embedded approach Referring to M ark [START_REF] Granovetter | The strength of w eak ties[END_REF] use of [START_REF] Polanyi | The great transformation[END_REF] notion of "social embeddedness" of economic activity, the systemic view proposes that the objectives and practices of strategy depend on the particular social system in w hich strategy -making takes place. Strategists often deviate from the profit-maximizing norm quite deliberately as societies have other criteria than just financial performance for supporting enterprises. M oreover, strategists might deviate from the text-book rules or rational calculation, because in the culture in w hich they w ork, such rules make little sense.

These deviant strategies matter because they can be carried out effectively. Strategy reflects the traits of particular social systems in w hich strategists participate, defining the interest in w hich they act and the rules by w hich they can survive. What is important to systemic theory are differences betw een countries' social systems and changes of such systems. The systemic studies are thus exploring the varying forms of business according to national interplay of state, familial and market structures. Whittington devotes much reflection to the cultural peculiarities of the very notion of strategy. By contrasting the classical and evolutionary perspectives on market and profitability w ith the current sociological appreciation of organizational environment in new institutionalist theory, Whittington exposes the ideological tone of strategic management and its role in reproducing the conditions of hierarchically organized capitalist society, in normalizing the existing structures of Western society, and in universalizing the goals of its dominant elites. Consequently, Whittington considers differences in strategy as enduring, and patterns as hard to change because they are "founded on real economic, social or political conditions " (Whittington 1993: 32). H e also says that the "strategy discourse" reflects ideological needs of the professional managerial class and that this discourse entered the business w orld via M BA programs at a time of changes in dominance. In Whittington's view , strategic theory mainly addresses the single audience of the practitioners themselves. H e therefore favours the socially-embedded perspective as the one that could helps managers to develop a sociological reflexivity, providing them w ith the aw areness of their social and political environments' munificence.

PROCESS

Whittington concludes by saying that strategy has to be understood as the contested and imperfect practice it really is. A s he reiterates in a more recent paper, it is necessary to "take seriously the w ork and talk of practitioners themselves " (Whittington 1996: 732). Such a new direction in strategy thinking -w hich he calls 'a strategizing perspective' is centred on the everyday activities of the strategists, "all the meeting, the talking, the form-filling and the number-crunching by w hich strategy actually gets formulated and implemented " (ibid). In his terms, the practice-oriented perspective is narrow er than the systemic one, but for that very reason, better as a starting point. Whittington suggests that "the unheroic w ork of ordinary strategic practitioners in their day-to-day routines " should become the focus of an investigation program aimed at obtaining "systematic know ledge of w hat typically the various practitioners involved in strategy-making really do ", and at know ing "the different skills strategy consultants, planners and managers actually use, or how they acquire them. " (Whittington 1996 : 734). H e also privileges observation as the suitable methodological device: "to understand strategizing better, w e w ill need close observation of strategists as they w ork their w ays through their strategy-making routines "(ibid). H e therefore proposes a new research agenda:

LEV EL OF AN ALYSI S RESEARCH I SSUES

M A N A GERS ORGA N IZA TION S H OW is strategy made? POLICY PLA N N IN G WH ERE is strategy made? PRA CTICE PROCESS
We might analyze the changing discursive practices of strategy butif not yet "enough talk"w e should also get real looking out for the changing physical technologies w ith w hich strategizing is actually done. Strategists manipulate spread-sheets, fill in cap-ex proposals, compile presentations and do so often alone and in silence, constrained and enabled by particular technologies (typically M icrosoft). (Whittington 2001: 734).

This under-socialized ("enough talk", "real", "physical", "alone and in silence") conception of practice is quite surprising coming from a theoretician previously inspired by over-socialized new institutionalist framew orks. Indeed, in the field of strategic management, Whittington appears to be one of the few researchers w ho strongly advocate the need to take into account the social foundations of strategic activities. H e lays special emphasis on the social embeddedness of strategic processes and he insists on the situatedness of everyday strategy-making routines. In our opinion, he is facing the paradoxical situation that Barbara Czarniaw ska has identified as the central issue in social sciences: the confrontation betw een social systems (as consisting of rules) and unruly practice. Whittington's under-socialized practice perspective can be mirrored w ith Thurman A rnold's 1 conclusion that "the w orld of practice must conquer the w orld of norms " (Czarniaw ska 1997: 190). We can guess that Whittington might be as "torn betw een his know ledge and the demands of the professional know ledge that he represents " as A rnold w as (Czarniaw ska 1997: 189).

In an attempt to escape both over-socialized and under-socialized view s of strategy-making, w e shall now explore the notion of practice through the lenses used by M ichel [START_REF] Certeau | The practice of everyday life[END_REF].

Restoring the N arrative D imension of Practice

M ichel de Certeau's analysis of consumption is oriented tow ards the ordinary practices of the consumers, w ho are defined as users of goods imposed on them by producers.

Indeed, as an offer of products to the consumers, production entails a logic of domination tow ards w hich consumers resist by developing inventive attitudes and practices. By mirroring consumption and reading, M ichel de Certeau reveals the tw o sides of consumption: on the one side, consuming entails a form of acceptance of an imposed offer of goods, w hile, on the other side, consumers are neither passive nor docile, they experience freedom, creativity and pleasureas readers do.

Commenting on empirical investigations of several situated social practices such as reading, talking, dw elling, cooking, w andering around, etc., M ichel de Certeau explores the scientific literature to clarify the purpose of the theorizing enterprise he undertakes:

It may be supposed that these operationsmultiform and fragmentary, relative to situations and details, insinuated into and concealed … w ithin devices w hose mode of usage they constitute, and thus lacking their ow n ideologies or institutionsconform to certain rules. In other w ords, there must be a logic of these practices. (de Certeau 1988: xv) A dopting this view provides a new w ay of looking at organizational practice because it leads to see strategic discourses as a production, as an offer of a (cultural) gooda text.

This w ay, w e might be able to suggest new forms of accounting for the w ays people read, use and transform this particular cultural product. Linstead and Grafton-Small (1992) have already opposed the production of corporate culture to the creative consumption of organizational culture by organizational members.

Using de Certeau's theoretical lenses requires complementing the analysis of the discourse of strategy (representation) and of the time spent attending strategic meetings (behaviour) by a study of w hat middle managers and employees "make " or "do " during this time and w ith these discourses. Their making or doing being devious and dispersed, it remains difficult to reach for the researcher as it often remains hidden. In organizations, employees and managers do not espouse, adhere to or share the "strategic" vision or intent of their "charismatic leaders". In their everyday activities, they actively interpret, criticize, learn and experiment possible attit udes and microdecisions to implement, or to resist to the multiple implications of strategic changes imposed upon them.

To better understand how to link practice to strategy, let us now move to definitions of strategy and tactic introduced by de Certeau:

I call a "strategy" the calculus of force-relationships w hich becomes possible w hen a subject of w ill and pow er (a proprietor, an enterprise, a city, a scientific institution) can be isolated from an "environment". A strategy assumes a place that can be circumscribed as proper and thus serve as the basis for generating relations w ith an exterior distinct from it (competitors, adversaries, clienteles, targets or objects of research). Political, economic and scientific rationality has been constructed on this strategic model. ( de Certeau, 1988: xix) Strategies conceal, beneath objective calculation, their connection w ith the institutional pow er that sustains them. Therefore, in this view , strategy is alw ays linked to the concept of pow er, as understood by Foucault (1977) w ho demonstrated that "the logocentrism of 'w riting' once translated into formal organization revolves around discipline" (Linstead & Grafton-Small 1992: 349).

De Certeau's definition of tactic is follow ing:

I call a "tactic ", on the other hand, a calculus w hich cannot count on a "proper" (a spatial or institutional localization), nor thus on a borderline distinguishing the other as a visible totality. A tactic insinuates itself into the other's place, fragmentarily, w ithout taking it over in its entirety, w ithout being able to keep it at a distance. It has at its disposal no base w here it can capitalize on its advantages, prepare its expansions, and secure independence w ith respect to circumstances.

The "proper" is a victory of space over time. On the contrary, because it does not have a place, a tactic depends on timeit is alw ays on the w atch for opportunities that must be seized "on the w ing". Whatever it w ins, it does not keep. It must constantly manipulate events in order to turn them into "opportunities". (de Certeau 1988: xix).

This view differs drastically from the traditional definition of tactic as a course of action follow ed in order to achieve an immediate aim and also from the definition of tactics as the art of finding and implementing means to achieve immediate aims. Interestingly, tactics (as the science of manoeuvering forces in battles) comes from the military vocabulary, as does strategy. De Certeau introduces tw o main differences, firstly a major change of level of analysisfrom global to individualand secondly the emphasis on the resistant nature of tactic, here meant not follow ing the strategy! Focusing on tactic sheds light on the creativity through w hich groups or individuals escape the "nets of discipline " and resist the logic imposed upon them.

Tactic reveals the extent to w hich ordinary intelligence is inseparable from everyday struggles and the pleasure they provide. M eaningful practice is neither determined nor captured by the set of social rules in w hich i t develops: it calls up a variety of hardly conscious, though crafty, tactics. M ultiple tactics appear through a creative bricolage that consists of "the process of association, of building the 'and, and, and' connections betw een actions and events and negotiating them w ith the 'readers' (such as other organization members)" (Czarniaw ska 1998: 20), that is, an ongoing production of narratives. This is congruent w ith the more general claimthat social life is a narrativemade by M cIntyre, and more precisely that "it is useful to think of an enacted narrative as the most typical form of social life" (Czarniaw ska 2001).

We must keep in mind that "it is central to the concept of discourse that it is reproduced, can be resisted and is subject to change and 'negotiation'" (Linstead & Grafton-Small 1992: 349). What narratives do is mainly resisting discourses. Therefore strategy in organizations can be seen as an expression of a strong program of integrative and radical change w hereas narratives "can be seen as belonging to (giving expression to) the 'w eak program', but it is abundantly clear that its existence depends on the existence of the 'strong program' (it needs something to differ from)" (Czarniaw ska 1997: 173). We can now summarize the contrast betw een the notions of strategy and tactic in the follow ing A s a consequence, the "practice of strategy" appears to associate tw o contradictory concepts thus being an oxymoron. It reveals that a direct turn to practice in strategic management research is clearly unproductive: both a theoretical and an empirical t rap.

A research agenda w ith the aim of describing the practices of strategists w ould lead to a purely instrumental and restrained view of strategy making that w ould favour univocal and far too naïve interpretations. That is w hy, at this point, w e w ant to advocate the need for a mutually beneficial dialogue betw een the discursive nature of strategy and interpretative approaches that define "organizing as narration" (Czarniaw ska 1997: 25).

In our understanding, Czarniaw ska's narrative variation of the new institutionalist perspective enables researchers to cope w ith the embeddedness of practices by including their symbolic reach w ithin a given organizational context. Thus, investigating strategy-making processes actually means operating a perilous shift from discourses of "grand strategy" to the minutiae of everyday practice through a systematic focus on narratives.

Exploring Strategic Practice : I nterpreting Two Empirical

Fragments

We w ill present tw o vignettes extracted from tw o empirical investigations on entrepreneurial activities w here w e used a micro-perspective [START_REF] De | Apprentissages collectifs et structuration de la stratégie dans la jeune entreprise de haute technologie -Etude de cas et éléments de modélisation procédurale[END_REF][START_REF] Czarniaw Ska | Interview s and organizational narratives[END_REF][START_REF] Eléonore | L'inscription sociale des discours et des représentations stratégiques dans l'industrie de l'Environnement[END_REF], 2000). Using de Certeau's theoretical lenses to reinterpret the narratives w e collected, w e w ill consider the interplay betw een strategic discourses and everyday narratives. These tw o vignettes illustrate some of the multiple w ays of playing the other's game and the pleasure of getting around a set of given rules.

Vignette 1: Playfully resisting dominant design

The first vignette illustrates a phenomenon that M ichel de Certeau considers as an emblematic figure of the tactics of ordinary practice called in French la perruque (the w ig). The "perruque" refers to the w orker's ow n activity disguised as w ork for his employer. w orker w ho indulges in "la perruque" actually diverts time from the organization to undertake activities on his/ her ow n that are free, creative and precisely neither directed tow ard profit, nor in accordance w ith strategic injunctions.

The vignette is extracted from a four-year investigation in a young French firm called TELIX, operating in telecommunicationsw hose products combine various advanced technologies and has a very short life cycleone year as an average. TELIX directly employs 70 peopleamong w hich 30 are gifted young engineers. Through successive interview s, w e collected at different periods the narratives of 14 individuals w ho had participated in the development of the firm since its foundation. This investigation gathered 400 pages of accounts and resulted in an extensive monograph of 100 pages. The monograph reconstructs both the history of the firm since its foundation, the main orientations taken for technical developmentand their correlated discussions that took place during the time of the study. A s such a short text prevents reproducing extensive parts of this monograph and situating precisely every actor, small parts of the accounts given by the actors are used here to illustrate their collective ability to set up a sort of hidden playground w here improvisation could take place.

In its first years of existence, TELIX had routinized a set of design practices that reinforced its subcontractor position by successfully designing products for its OEM (Origin Equipment M anufacture) clients and by developing very specific skills concerning the regulations in European markets. A few months later, TELIX faced sharp competition that dramatically endangered the innovative character of its products developed and improved through the official design rules. Indeed, the effor ts made to design TELIX's ow n products in accordance w ith official design rules and to organize an international retail netw ork w ere sporadic, lacked co-ordination and did not result in routinized practices. A s the launching of TELIX's ow n products w as del ayed several times, some important retailers refused to keep w aiting and decided to favour its competitors. These decisions strengthened the tendency w ithin TELIX to give priority to projects undertaken for industrial contractors, increasing TELIX's long t erm vulnerability.

Displeased w ith these orientations, M athieu, an engineer employed by TELIX since 1988, points out that "the firm is family-ow ned: if more responsibilities are gradually given to the personnel, in fact important decisions remain centrali zed by the founders A ntoine and Pierre. That's w hy sometimes concerning some decisions, you know you have to stay in the background… " H e continues:

Since TELIX's foundation, w ithin our technical department, engineers have been developing conniving rapports that go far beyond merely technical discussions.

Ow ing to the multiple and lively talks w e had w ithin our team to prepare technical decisions, everyone learnt a lot from each other and immediately mastered a comprehensive array of technical skills. We felt that this common experience had strongly draw n us together. Our w ork interactions rapidly transformed into buddy-buddy relationships. Our deep complicity allow s us to benefit from a huge scope of autonomy. This autonomy w e have gained enables us to cov er up some problems: w e have the possibility to do things secretly in order to avoid major crises and direct confrontations. We can develop marginal actions that go clearly against some decisions made by the Board. Indeed, as technical decisions are usually made in a great rush, w e are led to make up for mistakes. If a bad decision has been made, w hat kind of collective behaviour do w e have to adopt? That's w hy w e are sometimes led to run a different TELIX at the very heart of TELIX… François, in charge of the technical department, makes the observation that ... ambiguity w ithin our technical department w as very high at the beginning of TELIX. Today, it remains a natural w ay of functioning betw een the persons w ho have know n this period. This evidently entails a form of confidence and loyalty betw een us. It is this ambiguity that enabled us to explore ideas at the margins of the official decisions: w e encourage people to follow their ideas through and if it w orks, it is beneficial for the w hole team; but al so to feel responsible and autonomous in running the different design projects that w ere given to the team.

But it is obvious that this mode of functioning is very difficult to understand for an outsider and that trying to adapt to it requires great strength of w ill.

This point of view is corroborated by Denis, another engineer w orking in the technical department:

A mbiguity can bring positive results if people feel responsible for w hat they do. It reinforces exploration, the ability to take initiatives and to collect the necessary information. Ow ing to the specialization of every individual, a collective competence is able to expand in all directions, but it is the quality of our discussions and the ambiguity of our roles that do enable us to keep a global perspective on the design process. Together, w e have complementary and global skills: the quality of our relationships allow s us to reach and hold each other's know ledge even if w e do not have the same practice.

By cautiously engaging in a form of "illi cit playing" these three engineers among the design team had progressively structured a hidden playground w here they felt free to experiment w ith alternatives to the developmental path imposed by the rules of the official design game. Without taking the risk of opening a collective discussion about the relevance of the official design rules, these engineers applied improvised rules they found more suitable to achieve effective technical innovations. This concealed illicit playing lead them to develop an intensive production of inventive narratives that enriched both their personal interpretative repertoires and collective capacity to improvise in a different technological playground: they progressively explored different technical perspectives and found solutions to include high speed connections and radio devices into the products. View ing the commercial difficulties of TELIX as an opportunity, the three "free players" decided to reveal the divergent design process they had elaborated and managed to impose them on the design team. This sudden change in design allow ed the integration of radical technical innovations to the products and the progressive restoration over six months of TELIX's prevalent competitive position in the market.

The narratives of several organizational members highlight the minutiae of strategy-in-the-making as w ell as the various tricks and poaching tactics that shape their design practice. This vignette underlines the agonistic character of the perruque, an activity aimed at resisting, and the concepts de Certeau associates to it: kairos (opportunities), metis (ruses) and the "strategy-tactic duality". In spite of measures taken to repress or to conceal it, "la perruque" (or its equivalent) tends to infiltrate itself everyw here and has to be considered as an important part of strategy making. Indeed, the more an official playground is delimited through the actualization of a set of strict rules, the more illicit playgrounds are likely to emerge in order to resist and explore alternative w ays of doing things. For instance, the entrepreneurial team deals w ith a w ide range of technical possibilities and progressively restrains this scope to stabilize collective practices and routines enabling the formation of core competencies. This process leads to contextualize the creative efforts to be undertaken w ithin the firm and to favour some creative behaviours at the expense of other possible ones.

H igh tech as w ell as entrepreneurial activities deal w ith the unavoidable "playinggame" duality, as some areas are delimited as games w ith compulsory scripts to be follow ed, fostering simultaneously the ongoing emergence of playful resisting practices. This is a main strategic issue at stake w ithin entrepreneurial contexts in order to foster the progressive emergence of distinctive core competencies. Indeed, entrepreneurial activities are quite often the expression of a strong w ill to resist w ell -established or fixed rules that govern competitive games. In that sense, all the concepts articulated by M ichel de Certeau suit perfectly w ell the categories commonly used in the entrepreneurial literature: opportunities, tricks, poaching, w andering, roundabout means, playfulness, resistance, ruse, arrangement. A ll these productions are an "invention" of the memory.

Vignette 2: Consumption of discourses and production of narratives

The second vignette is based on the study of an emerging industry, the organizational field of the "green industry". We have been conducting interview s w ith "green intrapreneurs" (in charge of developing new ventures in parent firms), about how they w ere shaping their strategy. The aim w as to study how statements about strategy w ere structured and how , in turn, they w ere contributing to the on-going structuring process of the field (M ounoud 1997; 2000). These interview s w ere conducted w ith mixed feelings, as w e w ere deeply aw are that they w ere closer to an inquisition than to a mutual exchange of view s, but also that "the pow er w as on the side of the interview ee" (Czarniaw ska 2002). We w ere also aw are that collected stories w ere not new ly built, indeed they w ere "w ell rehearsed, and crafted in a legitimate logic, [as] it is highly unlikely that the interview ee resorts to a repertoire of narrative devices unusual for his/ her practice "(ibid: 746). This w as an advantage, not a shortcoming, as studying strategists' discourses requires remembering that "'meaningful insights into subjective view s' can only be expressed by 'familiar narrative constructs' " as Czarniaw ska comfortingly says.

Considering M ichel de Certeau's view on practice, tw o levels of analysis could be put forw ard.On the one hand, w e can consider that these texts are aiming at defining a Strategy, they try to set a proper place, than can serve as a basis for generating r elations w ith an exterior distinct from it, especially w ith competitors, regulatory affairs or parent companies. Thus they are defining and legitimizing the specific competence of venturing a green business. In order to do so, they w ill have to show rationality. On the other hand, w e can consider these texts as narratives, accounts of the social practices of their narrators in their everyday struggles, show ing their various tactics and tricks, proving their poaching ability.

We collected the narratives of 12 persons w ho w ere in charge of the development of the venture inside the parent company. This investigation gathered 150 pages of accounts that w ere interpreted as texts. A s such a short text impedes reproducing extensive interview s, only the interpretation built on the interview s w ill be used here to illustrate their individual ability to intertw ine strategic discursivity and tactical narrativity. The narratives of the "green intrapreneurs" highlight the minutiae of strategy-in-the-making as w ell as the various tricks and poaching tactics that shape their narrative practice.

We analyzed the interview s as texts , being interested as much in the content of the answ ers to our questions, as in the process through w hich they w ere built during the interview s, i.e. the enunciation process). We looked at what texts say and how they say it, looking for the various textual tactics and tricks used by the interview ees. Studying interview s as texts requires to stay as close to the texts as possible w hen analyzing them i.e. considering w hich w ords w ere used including how they w ere coining new expressions, w hat topic they w ere dealing w ith, how they related one to another through the use of "connecting w ords " (both causal and temporal).

Narrative tactics

Various narrative tactics have been observed:

Poaching

Borrow ing insights from M oscovici's theory of social representations, w e arranged a conversation betw een the texts from the interview s and institutionalized discourses on environmental management and protection (from various sources: politics, economics, ecology, science and media). These discourses are supposed to be structuring, and structured by, social representations. But as M ichel de Certeau underlined, the presence and circulation of a representation tell us nothing about w hat it is for its users. We must first analyze its manipulation by users w ho are not its makers. Only then w e can gauge the difference or similarity betw een the representation and the secondary production hidden in the process of its utilization. Close to Ellen O' Connor's (2000) idea of an embedded narrative, w e w ere able to identify three larger discursive arenas in w hich the narrators w ere poaching to build their ow n texts. Firstly, they w ere poaching into managerial know ledge, producing and reproducing organizational, technical, legal, strategic and social rules of control. For example new ventures, especially in large firms, w ere defined as follow ing the logic of core competences. Secondly, they w ere poaching into the science-based discourses of "Ecology " and "Economy", opposing the tw o to resist some implications of ecology and resolving the opposition betw een the tw o w hen necessary, for example by defining their action as saving pollution AND costs. Thirdly, they w ere playing w ith the "Environment" category, sometimes linking it to "N ature" that has to be protected and sometimes w ith "Regulation" that has to be follow ed.

H umour

One of the main competitor being Générale (now Vivendi Environment), one green intrapreneur w as very proud of presenting his company as "a specialist as opposed to a generalist" (w ith a smile) thus denying competence to is main competitor w ithout explicitly saying it; many anecdotes w ere meant for questioning innovation capability of the competitors or show ing the incompetence of environment policy makers; one largely spread tactic w as to oppose "de-pollution" and "anti-pollution", as tw o different market segments and know -how .

Plotting

Telling a story is about reporting a progression of events across time and uncovering the causal structure of the events. Because of the large amount of time they ask from their audience, narratives must have a point. They need a plot w hich must be based on a conflict or tension. H ere the links to various discourses are a resource: they might be invoked to highlight the differences betw een times (past, present and future), spaces (linking the new venture, its parent company, its competitors and policy makers) or discourses themselves. Such differences, or tensions, reveal not only the how (mimesis) but also the why (plot) behind organizational action. The specific plotting of a field organizes an interpretative repertoire, linking causal and temporal dimensions such as in the example below of the green intrapreneurship in the chemical industry:

BECA USE, IN TH E PA ST, w e used to be heavy polluters, N OW, A T PRESEN T, w e know a lot about pollution and how to depollute at low er costs, SO w e can take advantage of our experience and our core competences IN ORDER TO w e set up new businesses that generate profits for us, cost savings for our customers and pollution savings for the w hole society.

In their multiple w ays of dealing w ith such resources and constraints, interview ees attempted to build a discourse for imposing their ow n meanings, interests and desires on the emerging organizational field, settling a "proper place" and gaining a strategic dimension .

But w e must also consider that "narrativity haunts such discourses" (de Certeau 1988: 78). We better account for w hat texts do if, follow ing M ichel de Certeau's view , w e consider talking as a kind of consumption, or a secondary production, a creative w ay of using w ords and discourses. Local narratives are not structured by discourses but they are poaching from them, using them as resources for creating new expressions and meanings, w hich can rely on, or resist to, w ell-established and technocratic discourses.

Concluding Remarks

In this chapter, w e have suggested that investigating strategic practice requires a drastic change in both conducting research and theorizing in the field of strategic management.

In our opinion, the development of a practice-oriented research agenda in the field of strategic management can directly benefit from M ichel de Certeau's seminal contributions.

A pplying the w riting/ reading metaphor to describe strategy making helped us conceive strategy as an ongoing creative process involving not only w hat strategists produceor w rite -(budgets, plans, strategies), but also the w ays the members of the organization consumeor readtheir productions. A s a consequence, studying the practice of strategy implies paying more attention to middle managers and employees' "poaching ability", the multiple w ays through w hich, in their everyday activities, they understand, use and transform the strategic discourses that are imposed on them. We suggest that the change of focus from discourses of "grand strategy" to the minutiae of everyday practice necessarily leads to a theoretical articulation of strategic discourses and very ordinary narratives. M eaningful strategic practice is neither determined nor captured by the strategic discourses formulated at the top organizational level: it calls up a variety of hardly conscious, though crafty, tactics mainly aimed at resisting and transforming the logic of domination imposed by strategic discourses.

We contend that developing a practice-oriented research agenda in the field of strategic management w ould enable the pursuit of a beneficial dialogue betw een several theoretical framew orks such as:

-the narrative embeddedness of practice w hich leads to treat talk as action and not merely as talk (Czarniaw ska 1998),

-the situated temporality of practice [START_REF] Clark | Organizations in actions: competition between contexts[END_REF],

-the recursive nature of social life [START_REF] Rouleau | The social structuration of strategy formation in daily organizational life[END_REF][START_REF] Giddens | The constitution of society[END_REF].

This framew ork constitutes therefore an invitation to enrich the concept of "routinization". Usually, routines are seen as being merely an unconscious reproduction and acceptance of stabilized systems of rules (Jelinek 1979). Only a few authors (N elson & Winter 1982 ;[START_REF] Giddens | The constitution of society[END_REF] consider that routines include a creative part, as they imply an ongoing of reinterpretation of rules to adapt them toslightly or drasticallydifferent contexts. But in their rendition, this transformative capacity of routines is limited, allow ing for just some margins and evolutions w ithin a general frame of behaviour. These micro-evolutions, how ever, directly nurture a global process of change by fostering intrinsic variety and thus allow ing the progressive emergence of ad aptive behaviours. By considering that w ork practicessuch as organizational routinesare not only effortful but also emergent accomplishments, M artha Feldman reintroduces the importance of agency on routine interpretation and lays special emphasis on its performative nature [START_REF] Feldman | Organizational routines as source of continuous change[END_REF]. In a nutshell, a routinized behaviour alw ays consists of a creative interpretation of given rules in relation to a specific context. By analyzing four situations w here the outcomes achieved by a routine can be contrasted, she distinguishes three modes for routine change: repairing, expanding and striving (Feldman 2000: 621). In our opinion, M ichel de Certeauw hose theoretical framew ork is not discussed by M artha Feldmangoes even further. Indeed, the empirical observation of very ordinary practices such as w ays of cooking, w andering around, etc., proves that apparently passive behaviours, ordinarily performed routines or even hardly conscious practices are in fact inherently inventive : they reveal that reflective individuals actively try to understand to w hat extentand howthey can play w ithand resistprescribed social rules w ithin different contexts.

A ccording to M ichel de Certeau, this creativity expresses itself through a narrative ability that resists the rational calculations aimed at efficient action that characterize strategic discourses.

A nother conceptual contribution of M ichel de Certeau is to show that the recursive nature of very ordinary activities w ithin organizations is founded on an ongoing process of improvisation. Improvisation is often understood as a peculiar behaviour only suited to very specific organizational contextsw here people do not know exactly w hat rules to apply, in w hich the level of ambiguity and new is quite highthus allow ing a collective exploration to take place [START_REF] Weick | Organizational redesign as improvisation[END_REF](Weick , 1998 ; ;H atch 1999). If improvisation is often depicted as occurring outside organized routines or formal plans, it is not meant to occur by accident: it from a deliberate collective effort made to solve an unusual problem or to create a novel activity (M iner and al. 2001: 305). H ere again, M ichel de Certeau goes further by shedding light on the resisting nature of improvisation. A lthough organizational literature depicts mainly micro-improvisations as purely inventive practices, it seems that more attention should be paid to the resistance reflexes collectively developed by individuals involved in improvisations w ithin organizational contexts.

While executing the improvisation, its equivocal meanings are collectively explored through an intensive narrative activity. These narrations are aimed at preserving several plausible meanings of the fragments of experience new ly obtained rather than integrating all the consequences of the new behaviour adopted in a global and consistent explanation. Thus, improvisationsdefined as unreflexive resisting practicesshould not be considered only as a draw back or an impediment to achieve strategic change, but should be analyzed as a continuous and unavoidable process, contributing to an ongoing collective exploration and questioning of the sense-making principlesand their correlated rulesoffered by strategic discourses.

People, be they involved in the reproduction of routines or in improvised practices, actually develop their interpretive abilities and their social skills by enriching the perceived set of contexts, social rules and alternative behaviours available to them.

The ruling order serves as a support for innumerable productive activities w hile at the same time blinding its proprietors to this creativity (like those bosses w ho simply can't see w hat is being created w ithin their ow n enterprises). Carried to its limit, this order w ould be the equivalent of the rules of meter and rhyme for poets of earlier times: a body of constraints stimulating new discoveries, a set of rules w ith w hich improvisation plays. (de Certeau 1988: xxii) Only narratives can support these tentative explorations of alternative meanings, goals or w ays of doing: they room to a local transformative capacity by expanding the realm of available to perform activities and resist the ruling order imposed on by strategic discourses.

A s a final remark, w e w ould like to stress that, from an epistemological standpoint, such a practice-oriented research agenda w ill develop w ithin an intermediate space linking the realms of discursivity and narrativity:

The narrativizing of practices is a textual w ay of operating, having its ow n procedures and tactics. ... Shouldn't w e recognize its scientific legitimacy by assuming that instead of being a remainder that cannot be or, has not yet be, eliminated from discourse, narrativity has a necessary function in it, and that a theory of narration is indissociable from a theory of practices, as its condition as w ell as its production. ( de Certeau 1988: 78)

Table 1 : Four perspectives on strategy making (

 1 A dapted from Whittington 1993: 40)

		DELIBERA TE	EM ERGEN T
	OUTCOM ES
	PROFIT M A XIM IZIN G	CLA SSICA L	EVOLUTION A RY
	PLURA LISTIC	SYSTEM IC	PROCESSUA L

Table 2 :

 2

The '4 P' of strategy making

(A dapted from Whittington, 1996 : 732)

table :

 :

	A STRATEGY	A TACTI C
	Spatially or institutionally located	Time dependent
	Circumscribes a proper place	Insinuates in the Other's place
	Interacts w ith an exterior distinct	Turns events into opportunities
	from it
	Writing	Reading
	Reproduction	Improvisation, bricolage
	Discipline	A nti-discipline, resistance
	Strong program	Weak program
	A D I SCOURSE	A N ARRATI V E

Table 3 : Strategy as discourse, tactic as narrative

 3 These definitions shed light on the different areas w here organizational life has to be investigated. On the one hand, institutional arenas are necessary to legitimate, support and capitalize on an integrative discourse called strategy. On the other hand, it is necessary to bring practice back into the picture, thus accounting for the fragmentary, instantaneous and hardly conscious set of tactics upon w hich practice is based. There are innumerable tactics that constitute a varied stock of potential resistances to dominant

strategies. Everyday practices consist of a making w ithout intention of capitalizing on it, unable to take control over time, but that produce perceptible effects such as delays, resistances, diversions, rejections or displacements (translations for one's ow n purposes), etc.

 Weick, Karl E. (1995)Sensemaking in organizations. Thousand Oaks, CA : Sage.