Christian Henrich-Franke

Léonard Laborie

Continuities and Discontinuities during the Second World War

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This is the post-print version of : Christian Henrich-Franke, Léonard Laborie, « European Union for and by Communication Networks: Continuities and Discontinuities during the Second World War », Comparativ, vol. 28/1, 2018, p. 82-100.

European Union for and by communication networks: continuities and discontinuities during the Second World War

Authors: Christian Henrich-Franke and Léonard Laborie "It bore wrongly the title of 'European' because only a restricted number of European countries were members. Besides, this Union had no life in it; it disappeared at the end of the war." 1 The above mentioned comment by the Dutch High Director of Posts in the Directorate General for PTT 2 , F. A. Hofman, from 1947, criticises the European Postal and Telecommunication Union (EPTU), which was founded in Vienna in 1942, for a number of reasons: it was not 'European', it did not really work and consequently disappeared at the end of the war. This statement fits perfectly into the standard narrative of political science and historical research, which for a long time argued that the process of European integration started after the Second World War. In the last years this narrative has been supplemented by a long-term perspective underlining the importance of integration processes since the 19 th century and continuities since the interwar; however, the Second World War remains as a caesura and 1945 still counts as 'Zero Hour' (Stunde Null). 3 This article will question Hofman's statement by drawing the picture of a lively European organisation, which was part of a long-term development. It starts from the working hypothesis that the wartime EPTU was a catalyst for European integration and cooperation beside all political, economic and military upheavals. We argue that the EPTU was an important step toward the Europeanization of governance in the postal and telecommunication field and the emergence of a transnational European communication space. Within EPTU ideas as well as norms, values and practices of postal and telecommunication governance continued (nearly unbroken) from the interwar to the post World War II era. The EPTU can be seen as a first approach in formally transferring intra-European affairs away from the global organisations in the fields of postal and telecommunications relations: The Universal Postal Union (UPU) and the International Telecommunication Union (ITU). Negotiations on technical standards or rates should be limited to the parties involved in Europe. It also envisioned mobilizing communication networks to Europeanize the continent and create a sense of a European community. Among the key issues that were discussed within the EPTU were the creation of a common postal area and a transnational European telephone networkboth of which were necessities and catalysts for the creation of a transnational European communication space. This article raises a number of questions that address the EPTU's inner organisation and places it in a broader historical context: what role did the EPTU play for the long-term development of (European) PTT governance? How did an international organization function during the war? How did expert networks function under wartime preconditions? Finally, the question of the interpretative framework is raised: was the EPTU more about Germanisation or Europeanization of transborder communication networks, spaces and governance in Europe?

In 2005 Thomas Misa and Johan Schot put the 'hidden integration' of Europe on the agenda of historical research. 4 They called attention to the importance of transnational infrastructure networks in the history of European cooperation and integration. Since then a lot of studies have underlined their arguments. Research has been conducted on the building of European infrastructures, 5 their transnational governance [START_REF] Schipper | Infrastructural Europeanism or the project of building Europe on infrastructures: an introduction[END_REF] and their particular relationship to the 4 T., Misa, J., Schot, Inventing Europe: Technology and the Hidden Integration of Europe, in: History and Technology, 21 (2005), 1, 1-19. European Union and its predecessors. [START_REF] Henrich-Franke | Gescheiterte Integration im Vergleich: Der Verkehr -ein Problemsektor gemeinsamer Rechtsetzung im Deutschen Reich (1871-1879) und der Europäischen Wirtschaftsgemeinschaft[END_REF] Authors have shown a particular style of autonomous expert governance on the international arena for nearly all infrastructures. Experts negotiated networks and standards quite independently from national governments within specialized international organisations, even though infrastructures had an enormous impact on the economy and the society. [START_REF] Kaiser | Writing the Rules for Europe. Experts, Cartels, and International Organizations[END_REF] Postal and telecommunication services proved to be among the most autonomous infrastructure sectors since the 19 th century. [START_REF] Henrich-Franke | Regulating Intra-European Connections. Telecommunications and European integration 1950-1970[END_REF] The focus, however, was either on the 19 th century 10 and the interwar period or on European integration after 1945. [START_REF] Ambrosius | Integration of Infrastructures in Europe in Historical Comparison[END_REF] The war only mattered in a few publications with a strong national angle. [START_REF] Laborie | L´Europe mise en réseaux. La France et la coopération internationale dans les postes et les télécommunications (années 1850 -années 1950[END_REF] A wartime organisation like the EPTU must be seen as probably the 'most hidden' story about European cooperation and integration. At the same time, it is not an isolated story. The EPTU is a strong element of National Socialist Internationalism and the Nazis attempts at reshaping the European order "under Axis leadership." [START_REF] Herren | Neither this Way nor any Other. Swiss Internationalism during the Second World War[END_REF] We assume that the EPTU has not yet been fully embraced by the historiography because of the missing interest of the relevant actors in the PTT sector in referring to wartime cooperation. Both the German and the non-German experts and politicians did not want to mention their participation in an organisation that was co-sponsored by the National Socialist government. To place the EPTU within the continuities of cooperation and integration in 'PTT Europe' was not timely. Therefore only a few proposals for a closer cooperation among the European PTT administrations after 1945 and just a few of the numerous contemporary articles on 'European PTT integration' in the 1950s and 1960s made a (depreciative) reference to the EPTU. 14 In contrast to that, a number of German articles describes the origins and working procedures of the EPTU from the wartime period. 15 Some of them even correspond to the usual style of reporting on international PTT conferences in the interwar or post-war times. 16 In a first step this article gives an overview of the origins and functioning of the European Postal and Telecommunication Union in a chronological order. In a second step continuities and discontinuities of intra-European PTT cooperation from the interwar period up to the 1960s will be discussed regarding actors, institutions, and contents of negotiations. Finally, the paper draws some preliminary conclusions regarding the questions of the emergence of a transnational communication space and of a Germanisation or Europeanization of transborder communication networks and flows. This article is based only on a first analysis of archival sources from the foreign offices and the PTT administrations in Germany and France. Much more research is necessary and will be carried out within a DFG-ANR sponsored research project to draw a thorough picture of the complex developments surrounding the European Postal and Telecommunication Union. 17

Origins and functioning of the European Postal and Telecommunication Union

International cooperation in the fields of postal and telecommunication services in the interwar period was shaped by two characteristics. Firstly, the tasks of the Universal Postal Union and the International Telecommunication Union increased remarkably due to technical innovations. National technical networks required ever more coordination at the national boundaries if they were to be used for transnational communications. The ITU responded to the technical demands by setting up three technical study groups -the consultative committees for telegraph, telephone and radio (CCIT, CCIF, and CCIR). On the postal side, the development of airmail also generated new specific international initiatives. In both organizations strong transnational expert communities had emerged, which shared perceptions on how to build transnational networks in Europe and the world. Secondly, both Unions, 14 F., Koller, Die Entstehungsgeschichte der Europäischen Konferenz der Verwaltungen für Post und Fernmeldewesen, in: Archiv für das Post-und Fernmeldewesen, 12 (1960) which had initially a European membership composition in the 19 th century, increasingly globalized their spatial scope. The USA especially became a strong actor on the telecommunication scene. Moreover, the US and the British telecommunication industries became dominant actors on the European markets at the expense of national equipment producers in Germany, France and many other European countries.

In 1940 both Unions officially stopped their activities due to the outbreak of the Second World War -only the international bureaus kept on working. The interruption of transborder cooperation in both international organisations did not stop the operation of transborder postal and telecommunication services. Especially within the war infrastructure networks for postal and telecommunication services needed to be kept running. Societies and the military depended on postal and telecommunication services regardless of any occupation by foreign troops.

At a meeting of Italian and German telecommunication experts in Bolzano in November 1940 the attendees considered for the first time during the war the setting up of a European working group that should continue the standardization of telecommunication equipment which had been carried out by the ITU's consultative committees for telegraph, telephone and radio up to the outbreak of the war. 18 They envisioned a working group that was intended to be limited to European participants. Just a few weeks later the ITU's international bureau in Bern cancelled the Administrative Telegraph and Telephone conference, which was scheduled in 1942 in Rome. This triggered both administrations to put their idea of a European working group into practice. The Italian, Giuseppe Gneme, who headed the study group IX within the Consultative Committee for Telephony (CCIF), especially urged for a continuation of the ongoing studies. Both administrations discussed a first statute for the working group and evaluated the documents of the ITU's three consultative committees already at a second meeting in Munich in January 1941 in order to define the topics that the working group should continue to discuss. 19 Motivations for the engineers from Germany and Italy were manifold. Firstly, they wanted to continue technical standardization on a pan-European level and discuss developing technologies such as semi-automatic dialling systems or the physical characteristics of voice transmissions. In a memorandum for their governments, they argued that "the extension of 18 Protocol of the meeting between the Italian and the German in Bolzano, 30 November 1940, Bundesarchiv Berlin, R4701/12284. 19 Protocol of the meeting between the Italian and the German in Munich, 15-18 January 1941, Bundesarchiv Berlin, R4701/12284. telephone networks continues during the war. It is necessary to take into account the needs of a pan-European network in order to make the investments profitable after the war". 20 Engineers wanted to standardize the technical networks that were necessary for the creation of a transnational communication space, even though they did not explicitly speak about it.

Secondly, the engineers and the national telecommunication industries hoped to decrease the influence of the US and British telecommunication industries which gained a strong position on the international market in the 1930s. A European working group promised to "repress unwanted influence while examining and negotiating equipment". 21 Remarkably, even the Soviet Union's administration was invited to participate in the working group. 22 Facing the official government representatives, the experts sold their working group as a political project. In a memorandum to the 'Supreme Command of the Armed Forces' (Oberkommando der Wehrmacht), the German general director for post, Friedrich Risch,

argued "I intend to make the working group of postal and telecommunication administration an integral part of the restructuring of intra-European relations … I would also like to increase the German influence on the development of civil postal and telecommunication systems, especially in the neutral countries". 23

From the beginning the project was strongly supported by the German Foreign Office and the German government -probably also the Italian one. The working group fitted perfectly into the national-socialist attempts at reshaping the European order; however, government representatives asked for a permanent and visible international organization instead of a more informal working group. Such an organisation was meant to be a symbol for a European Community according to the visions of 'National Socialist Internationalism' -a European order with Germany as regulatory force. For the German government it was of crucial importance to regain influence on the international arena even in peacetime. This, of course, meant a disempowerment of France and a transfer of competences into German responsibility. Apart from all support for the PTT engineers, the political supervisors, especially within the German Foreign Office, set clear boundaries for wartime cooperation in 1940 and 1941 and compelled the PTT administrations to compromise in many respects. The Foreign Office, for example, kept an eye on the participants and the language of the conference. This meant that the participation of France, Belgium and Greece was left in limbo and that the French language, which had been the international PTT language since the 19 th century, was officially no longer allowed. The most important intervention concerned the organizational form. By order of Adolf Hitler himself, an international organization ought to be founded, which was also important for propaganda purposes, instead of an informal working group. 24 In preparation for the founding of the European Postal and Telecommunication Union, the Reichspost concluded a number of bilateral agreements with the axis powers and the occupied territories. These contained new rates and a general reduction of postage. The Reichspost made a number of concessions to their contractual partner in order to demonstrate 'peaceful intentions' and to facilitate the signing of agreements under war conditions. Negotiations were also carried out with neutral countries; however, hardly any contract became formally concluded. Subsequently a network of bilateral agreements emerged up to summer 1942.

France, which was subdivided into two separate zones, including for postal and telecommunication traffic, had a specific position in the preparations because it was isolated and not included in new rates and rates structures. 25 Following preparatory talks with delegates from Denmark, Italy and Hungary in Innsbruck the Reichspost in August invited 18 European administrations -only Belgium, France, Great Britain, Ireland and the Soviet Union were not invited -to the European Postal and Telecommunication Congress in Vienna in October 1942. Japan was invited to send an observer.

Among the 18 assembled administrations of 17 European countries, 14 officially founded the 'Europäischer Post und Fernmeldeverein' (European Postal and Telecommunication Union) by signing the organization's convention. 26 Only the two administrations from Sweden had to cancel their participation due to a government order. 27 Belgium, Greece and France, which were totally or partially occupied countries, did not attend. The French PTT administration had received from the Armeefeldpostmeister in France an invitation to attend the congress, at least as an observer. 28 Despite some hesitations, it was about to send a group of nine delegates when the Reichspost finally signified that it was no longer invited. This late and possibly humiliating rebuff was a reaction to be expected to the preconditions regarding working language and currency unit asked for by the French PTT administration in accordance with the Finance ministry. Within the committees a large number of sub-groups for individual aspects were established.

26 Founding members were Albania, Bulgaria, Croatia, Denmark, Finland, Germany, Hungary, Italy, the Netherlands, Norway, Rumania, San Marino and Slovakia. Spain and Switzerland participated as observers. Even Japan was represented. 27 Correspondance of the Reichspostminiterium with the Swedish administrations for postal services and telecommunications, Bundesarchiv Berlin, R4701/11631. 28 Victor Pignochet, direction de la Poste et des Bâtiments, "Historique des pourparlers concernant la Conférence de Vienne (12 octobre 1942)", Archives nationales (AN, Pierrefitte), F90 bis/8436. See also: L., Laborie, L'Europe mise en réseaux, 332-336.

The EPTU received a constitution and three non-binding regulations, in which standards for rates, operation and technology were laid down as recommendations. The constitution provided the EPTU with an international office in Vienna (and not in Switzerland as was the case with the UPU and the ITU), funded by the members on a proportional basis. It also provided for a litigation procedure and a revision of the convention by a conference of experts, each with equal voting rights, with one vote per member country.

In 1943, the EPTU clearly demonstrated that it was a lively organisation, in which PTT experts from nearly all parts of Europe met to discuss the operation of postal and telecommunication networks. Cooperation intensified. The permanent office in Vienna since April 1943 carried out work, which was done before by the UPU and ITU bureau, e.g. the compiling of a European table of rates. Next to technical standards, the Union negotiated postal and telegraph rates, e.g. the abolishment of transit rates. The three permanent committees started working both within their sub-groups as well as within plenary meetings. Thirdly, the experts from the Reichspost increasingly demanded a liberalisation of the Foreign Office's strict policy against France. French PTT engineers and postal administrators had been close partners before the war and it was clear to their German counterparts why they should be treated as second class participants. The changing war situation enabled the Reichspost to make stronger claims in favour of their French counterpart. 30 Against this background the German Foreign Office made a number of concessions. Since late spring 1943 the French were allowed and even forced to participate informally in the EPTU's work. French delegates could enter all meetings. All documents were translated into French and they even got an interpreter. The French delegates recognised their changing situation and acted self-consciously, for example on the language question. Nevertheless, French was not recognised as an official language of the EPTU -a key demand of the French PTT. 31 The EPTU in 1943 indicated the ambivalent policy of many European countries, especially the neutral Swedish and Swiss government. On the one hand, critical voices were raised outside the PTT sector. The Swedish newspaper, Dagens Nyheter, for example, criticised that "the Vienna agreement is solely built upon German rates and weight scales: One power rules and decides. We are, however, not used to such dealing with international affairs or to any group of powers that declares: This is Europe! Fortunately, Europe is too big for this." 32 On the other hand, the PTT administrations from neutral countries had regular contacts and exchanged information with the Reichspost and the EPTU office.

In the second half of 1944 the war developments subsequently stopped the work carried out by the EPTU, even though the PTT experts from the Reichspost made every endeavour to continue the committees' work. Madeleine Herren accurately labelled the German attempts to pursue cooperation as "internationalisation strategies…with meticulous bureaucratic enthusiasm." 33 The Reichspost mentioned among the most urgent topics a future European network for airmail services. It is remarkable that, dealing with the Foreign Office, the PTT administration now completely reversed the arguments regarding the legitimacy of transnational cooperation. The EPTU was now considered not as a political symbol but as a completely apolitical working group. This time Risch wrote to Martius that "I will finally mention that there is a clear difference between a participation of states and representatives of branches. The committee's meeting is not a European organisation's one according to international law but a purely technical affair". 34 When the permanent office finally cancelled the meeting of the committee for telecommunication services, which was scheduled in October 1944 in Vienna, the EPTU had come to an end. Apart from some Eastern Europeans and Norway all other European postal and telecommunication administrations wanted to await the end of the war to continue international PTT cooperation. 35 31 Report on Franco-German negotiations in Berlin 20-22 June 1943, Bundesarchiv Berlin, R4701/11618. 32 Dagens Nyheter, 7 April 1943, Bundesarchiv Berlin, R4701/116969. 33 M., Herren, 'Neither this Way nor any Other', (12). 34 Letter from the General Director for Post, Friedrich Risch, to the Foreign Office, Martius, 13 June 1943, Bundesarchiv Berlin, R4701/116970. 35 Answers of the European PTT administrations to the invitation to the meeting of the committee for telecommunication affairs, Bundesarchiv Berlin, R4701/116970.

Continuities and Discontinuities in European PTT governance

At first sight, the EPTU looks like a moment apart, a brief wartime experiment in technical cooperation over-determined by a specific context of hegemony. There is no question that contextual factors shaped the EPTU, an institution "that only lasted as long as [Hitler] did", as an English postal officer would later pinpoint. 36 But from the perspective of the longer history of postal and telecommunication institutionalized multilateral cooperation, dating back to the 1860s-1870s, it is less a parenthesis than a link in the evolution of European PTT governance. 37 Indeed, the EPTU is deeply connected with pre-war and post-war developments. This can be observed on three distinct levels -individuals, institutions and content.

(1) Individuals: A human chain linked up developments across various political contexts. As they generally remained in charge for a long time, many experts and high civil servants involved in the EPTU knew each other from earlier years. They had already taken part in international cooperation before and some would also remain involved after the war. They were part of transnational expert groups which had emerged long before the outbreak of the Second World War. A more systematic overview is needed but at this point some individual trajectories can illustrate this continuity. Gunnar Albrecht, for instance, was the director of the Finnish postal administration since 1919. As such, he participated in most of the international meetings in the interwar period. He showed great commitment to the EPTU plan and presided over the congress in Vienna, before retiring in 1943. 38 He knew Karoly Forster from Hungary or Gunnar Lager from Sweden, who already represented their respective postal administrations during the 1930s. Forster was an active member of the 1942 congress and supported the EPTU convention, before retiring in July 1945. A year later, the international bureau of the Universal Postal Union in Bern publicly acknowledged its long commitment to international relations: "In the name of all the numerous friends he acquired at the various international manifestations he attended, we beg Dr. Charles de Forster to accept our very cordial wishes for a long and happy life in retirement". 39 As already mentioned, the Swedish Post Office, headed by Lager, wanted to join as well, but its Foreign Office obliged him to decline the German invitation, according to a Swiss observer. 40 Nevertheless, on the nonofficial level -outside the EPTU -they all stayed in contact about the issues that were negotiated in Vienna.

In the telecommunication sector too, it seems that a large number of the delegates who were present in Vienna had participated in the ITU's work in the 1930s. Some German and Italian experts in particular participated in international cooperation before and would continue after.

Giuseppe Gneme, the head of the EPTU's study group for telecommunication, already attended the International Radio Conference in 1927 and became a member of the ITU's Administrative Council in 1953. 41 Helmut Bornemann, who was responsible for the German participation in all telecommunication matters within the framework of the EPTU, continued to represent Germany in all international committees up to 1961. He even represented Germany in the Spaak-Committee which in 1955 reflected on further steps towards European integration prior to the founding of the European Economic Community. 42 All in all, these men formed a stable community cemented by shared knowledge and values, and co-working experiences. Interpersonal contacts before the foundation of the EPTU shaped the way people behaved and interacted within this organisation. In the same respect, contacts during the war became part of post-war developments. While Gemany was not officially represented, European engineers informally asked Bornemann, a German, to give his particular German point of view on the future of the European telephone network in 1948.

They remembered that Bornemann had contacted them during the war at a time when they did not participate in the EPTU. 43 (2) Institutions: The preparation and organisation of the Vienna Congress, and the way the EPTU actually functioned corresponded with the ITU's and UPU's way of engaging in international technical relations. Founders and participants did not reject the past but rather claimed connections to it. They openly tied up to the interwar developments of a decreasing Eurocentric UPU and ITU. In the covering letter inviting to the congress, the German PTT minister, Ohnesorge, placed this event in the tradition and the legal framework of these organisations. To justify the German initiative, the letter explained that "the Consultative 40 M., Herren, 'Neither this Way nor any Other', (12), 184. 41 International Telecommunication Union, Annual Report by the Secretary General of the International Telecommunication Union -1953, Geneva 1954. 42 Germany in the Official protocols and reports by the German delegation on the sub-committee for PTT, Politisches Archiv des Auswärtigen Amts, Berlin, B16-7. 43 Correspondance on international issues by Helmut Bornemann, Bundesarchiv Koblenz, B257/20556.

Committees -CCIF, CCIT, and CCIR -are currently incapable of work. Therefore, the technical development of telecommunication equipment threatens to pursue different paths in

the countries of Europe. This situation is likely to result in long lasting and profound disadvantages for the administrations." 44 During the congress Karoly Forster, for instance, put the stress on late 1930s' achievements in European airmail regulation within the UPU framework as a starting point for further postal cooperation. 45 According to the minutes, the debates during the congress were free from Nazi doctrine. They were all about the technical properties needed to maintain and further develop Europe as a transnational communication space.

This was not (or not only) a discursive strategy. Inscription within the tradition was also visible in the procedures and the institutional setting. According to traditional UPU and ITU procedures, the Reichspost issued preparatory documents for the topics that should be discussed in Vienna and the administrations were asked to send in their comments to the documents prior to the conference so that all conference participants could read the comments in advance. As this procedure was the usual one the administrations sent in their comments to the documents. Remarkably, even the neutral countries' PTT administrations from Switzerland and Sweden forwarded comments to the founding conference in Vienna. As usual, the language among experts was technocratic, apolitical and fully factual, whereas the correspondence with the foreign offices was shaped by political considerations. 46 EPTU's founders repeatedly stressed their intention to embed the newly created organisation within the ITU and UPU, and to turn it into one of their regional unions. 47 Both the ITU and the UPU allowed for regional unions. Southern American countries later joined by Central and Northern American countries had thus founded the Pan American Postal Union between 1911 and 1921. This was the major precedent. Other regional unions had emerged on a smaller scale, for instance the Scandinavian Postal Union in 1919. From an organisational point of view (international office, proportional financial contribution, voting rights, etc.), the EPTU also strictly followed the institutional path drawn by the ITU and the UPU. It innovated only in one aspect though, by breaking with the model of separated international organisations for postal services and for telecommunications. Since the founding of the Austro-German Unions for Telegraphy and Post in 1849 and 1850 the postal and the telecommunication sectors had been completely separated on the international level, even though they were united within most administrations on the national level. This new institutional format would be continued after the war.

In this machinery, experts were clearly in the driving seat as it was the tradition since the ITU introduced the administrative conferences at its plenipotentiary in St. Petersburg in 1875.

They could probably not do whatever they wanted, but political checking was not institutionalised. There was no committee of ministers supervising their work and the EPTU stood on its own on the international scene. This institutional design reflected a debate of the interwar period about the experts' autonomy in international policy making. Despite some pressure to join the newly created League of Nations, the ITU and UPU remained independent from any other body after the First World War. When the French Foreign minister Aristide Briand proposed to create a framework for closer cooperation between European countries in 1929-1930, he pointed out that experts had to be kept under political "control and influence" [START_REF]Mémorandum sur l'organisation d'un régime d'union fédérale européenne[END_REF] , meaning a ministerial supervision and a connection of their meetings to the League of Nations secretariat. In the case of postal experts, the plan failed. At that time, the French, German, Swiss and British postal officials coordinated their opposition to any plan to create a European Postal Union. Typical of 'technocratic internationalism' thinking [START_REF] Lagendijk | Technocratic Internationalism in the Interwar Years. Building Europe on Motorways and Electricity Networks[END_REF] , one of their main concerns and arguments was that they already cooperated, in particular in airmail regulation, and that their 'apolitical' way of conducting international relations was the only sustainable one. After all, they still cooperated within UPU and ITU in 1938, while Germany and Italy had withdrawn from the League, and the USSR was about to be excluded. [START_REF] Quenot | Note pour Monsieur le Ministre (Cabinet)[END_REF] In their perspective, technology had to be kept out of politics for the sake of the services and their users. Within the EPTU as before the war, experts discussed matters of mutual interest without any close governmental control. They had envisioned an informal working group of experts in 1941 and were keen to come back to this argument as soon as they deemed it profitable -hence Risch arguing to the German Foreign Office that "The committee's meeting is not a European organisation's one according to international law but a purely technical affair." [START_REF] Risch | [END_REF] This autonomy remained a major issue in the post-war period. Many experts pointed out the risk of a 'political contamination' in case of an institutional linkage between the ITU and the UPU on the one hand and the new United Nations framework on the other. [START_REF] Laborie | Fragile Links, Frozen Identities: the Governance of Telecommunication Networks and Europe (1944-53[END_REF] The ITU and the that "the Conference shall be independent of any political or economic organisation". [START_REF]Arrangement instituant la Conférence européenne des Administrations des Postes et des Télécommunications, 26 juin 1959[END_REF] (3) Content: During the Vienna conference, the delegations discussed all aspects of intra-European PTT operations following the CCI's working procedures and topics. 54 In order to set the agenda, participants first reviewed the work done in the 1930s having in mind the return, sooner or later, to peacetime conditions. The discussions were tainted by war conditions but they were not penetrated by them.

Even the most emblematic new regulations issued by the EPTU did not come out of the blue but instead were rooted in earlier proposals and debates. Indeed, the abolition of transit fees and the adoption of a single European rate for postal and telegraph communications materialized ideas discussed for decades, first within expert circles, and afterwards within larger Europeanists circles. Transit fees were discussed from the very first multilateral postal meeting in 1863. [START_REF] John | Projecting Power Overseas: U.S. Postal Policy and International Standard-Setting at the 1863 Paris Postal Conference[END_REF] Countries like France had a strong financial interest in maintaining substantial transit fees due to their geographic position and resisted lowering them. Others on the contrary called for a reduction and progressively succeeded. After the First World War, inflation and fiscal needs to recover from war devastations led to an increase in transit fees and rates for international communications across Europe. This was how movements keen on uniting Europe turned back to communication networks and called for the creation of a 'European PTT regime' or a European Postal Union. [START_REF] Laborie | Enveloping Europe: Plans and Practices in Postal Governance[END_REF] Such a step was considered to be the most advanced proposal by the promoters of the Briand plan during the 1930s, and Briand himself proposed to put it on the agenda of the newly formed League of Nations' Commission for the study of European Union. [START_REF]Service d'information et de presse du ministère des Affaires étrangères[END_REF] Apart from facilitating cross-border communication, there was another interest in its enforcement. If postal networks were already connected across borders, they materialised and visualized through stamps in particular national communities and symbols instead of international ones. The idea was to turn these networks into engines of a new European dynamic. But the project failed to take shape twice before the war. The creation of the EPTU was a way to realise this project -except for the stamp, as, it seems, the idea of issuing a common single stamp materializing the European Union was not discussed; some countries however, like Germany and Norway, issued their own stamps commemorating the 1942 Vienna congress.

After the war, the idea of uniting Europeans through communication networks surfaced again quickly. The EPTU was seen as an embarrassing legacy. Ahead of the Hague Congress in 1948, F. A. Hofman, a Dutch postal officer, proposed to create a European Postal Union. His deprecatory mention of the EPTU, quoted as an introduction to this article, cannot obscure the fact that the content of his proposal was remarkably similar to what was realised during the war: it was about common rates, the abolition of transit fees, the coordinated development of airmail, and the standardisation of postal and telecommunication regulations. [START_REF] Hofman | The Usefulness of an European Postal Union and its Task[END_REF] The idea was taken up as early as August 1949 in the Council of Europe, a new arena resulting from the Hague Congress. In November 1951, the General Secretariat of the Council of Europe presented a memorandum which briefly mentioned the EPTU but did not refer to its source when it claimed that "the meshes of the Universal Postal Union's and International Telecommunication Union's services network are still far too large for the European continent". 59 Yet, this was almost exactly the same words which were used by Risch in October 1942 to explain the creation of the EPTU. 60 The Council of Europe could not make any explicit affiliation with this wartime form of unification. When Hans Schuberth, Christian Social Unions' PTT minister for the Federal Republic of Germany, championed the cause in the early 1950s, he admitted that "these ideas (…) are not new; one can even almost admit that from a political and historical point of view, they have been in the air for a long time", 61 but did not mention the EPTU. This organisation progressively disappeared from the official memory of European technical cooperation. and decides." 62 True, rates and weight scales now in use from Narvik to Syracuse corresponded to those of the Greater Reich. From this perspective, the EPTU first and foremost mirrored a de facto German hegemony over Europe, and tended to reinforce it under the veil of cooperation. Even if it was not a direct expression of brutal force, it resulted from it.

This said, it is worth considering that it did not prevent PTT administrations from neutral countries such as Sweden from having regular contacts and exchanging information with the Reichspost and the EPTU office. Furthermore, the rates and weight scales at stake were also new and more expansive regulations for German users, which included domestic German communications. After all, the Reichspost as operator of an important transit country for communication flows in Europe spoke in favour of disposing of transit rates. In any case, as already seen, Hofman condemned the EPTU in 1947 for the same reasons, as he understated that it was all about German domination.

In France, at the end of the war, the Foreign Office claimed that it had declined the German invitation to cooperate with the EPTU and that this was an act of resistance to Nazi hegemony. [START_REF]'activité de la sous-direction des Unions de juin 1940 à août[END_REF] Rather positive at the beginning about the prospect of a French participation, the diplomatic bureaucracy later opposed any formal membership for political reasons, when it became clear that German and Italian would become working languages and that the accounting unit would be changed from the Gold Franc to the Reichs-Mark. For years, the French Foreign Office had indeed been vigilant about maintaining these soft power tools across all international organisations. In many ways the EPTU participated in its own field to the dismantling of what a large part of the German elites saw as an unfair international order set up at the end of the First World War and the signing of the Versailles treaty. [START_REF] Schulz | der Völkerbund und die Frage der europäischen Wirtschaftsordnung 1925-1933[END_REF] While French and Anglo-American actors had taken control over international cooperation, one of the missions of the EPTU was indeed to return techno-industrial German interests to the forefront of the European scene.

According to Madeleine Herren, the EPTU was a strong element of National Socialist Internationalism and the Nazis' attempts at reshaping the European order "under Axis

  5 A., Badenoch, A., Fickers, Materializing Europe. Transnational Infrastructures and the Project of Europe, Houndmills 2010; A., Kaijser, E., Van der Vleuten (eds.), Networking Europe. Transnational Infrastructures and the Shaping of Europe 1850-2000, Sagamore Beach Ma. 2006.

Furthermore, wartime economic

  reasons spoke in favour of a European standardization of 20 Letter from the General Director for Post, Friedrich Risch, to the Foreign Office, Martius, 18 December 1940, Bundesarchiv Berlin, R4701/12284. 21 Notice on a meeting between representatives from the Reichspost and the Foreign Office, 28 December 1940, Bundesarchiv Berlin, R4701/12284. 22 Letter from the General Director for Post, Friedrich Risch, to the Soviet Union's PTT Director, Bergeitschuk, 13 March 1941, Bundesarchiv Berlin, R4701/12284. 23 Letter from the General Director for Post, Friedrich Risch, to the Supreme Command of the Armed Forces, undated, Bundesarchiv Berlin, R4701/12284. equipment. Standards minimized the types of equipment and enabled the industry to release manufacturing capacity for military equipment.

Map 1 :

 1 Participants and observers of the Vienna Congress 1942 Institutionally, the Vienna conference was subdivided into four committees, of which the first three were turned into permanent institutions after the conference: (1) Committee for postal services; (2) Committee for telecommunication services; (3) Committee for telecommunication technology and (4) Committee for editing of the union's convention.

  Committee 1 met in Copenhagen in June 1943 to discuss postal services, meanwhile Committee 2 met in Vienna in September 1943 to discuss telecommunication services. The working groups for telecommunication technology established contact to negotiate standards and recommendations. The war hardly mattered in their negotiations as they focused on civil applications. Even more, the experts included war enemies like Great Britain in their plans for a peacetime European telephone network.The negotiations in 1943 must be seen as a privileged form of cooperation at a time when international conferences were completely abandoned by the German government. In a remarkable techno-political way the PTT experts made use of their political value. Regarding the meeting of Committee 2 in Vienna, they forwarded policy arguments to the Foreign Office to promote the conference as early as in April 1943. The Reichspost's General Director, Friedrich Risch, underlined in a letter to the Foreign Office's head of the department for communications, Georg Martius, "that the European Postal and Telecommunication Union had come into being because of the explicit order of the 'Führer'. … The Union, therefore, is not just of technical but of political importance as it demonstrates to the war enemies the unity of the European countries".29 If the conference did not take place, "this would result in a momentous setback for the flourishing European Postal and Telecommunication Union".29 Letter from the General Director for Post, Friedrich Risch, to the Foreign Office, Martius, 30 April 1943, Bundesarchiv Berlin, R4701/116969.

Map 2 :

 2 Member countries of the EPTU and semi-formal participants in 1943In the course of 1943 the German Foreign Office had to rethink its attitude towards France for a number of reasons. Firstly, the more the Germans lost Italy as the second major pillar within EPTU because of the allied invasion and the subsequent regime change in this country, the more the organisation opened up for France. Secondly, a claim for pan-European responsibility of the EPTU could only be made if France was part of it. Any participation by neutral countries like Sweden or Switzerland depended on French (and Belgian) membership.

44

  Invitation to the Vienna Congress by Reichspostminister, Ohnesorge, Bundesarchiv Berlin, R4701/12285. 45 Europäischer Postkongress Wien 1942. Berichte und Vereinbarungen. Congresso postale europeo Vienna 1942. Relazioni e accordi, Berlin 1943. 71-73. On airmail regulation: L., Laborie, A European System for a New Network: the Airmail Service with No Surtax in the 1930s, in: M., Le Roux (ed.), Post Offices of Europe. A Comparative History, Paris 2007, 413-427. 46 Correspondance of the Reichspost with the different European PTT administrations, Bundesarchiv Berlin, R4701/12285. 47 F., Risch, The Tasks and Aims of a European Postal Union, in: L'Union postale, 67 (1942) 9, 247-253 and F. Risch, European Congress of Vienna, in: L'Union postale, 67 (1942) 10-11, 291-294.

  UPU finally became specialised agencies within the United Nations family in 1947. With regard to closer cooperation in the European area, the experts were in their majority suspicious about proposals aiming at a political supervision of their work. Helmut Bornemann, for example, used the same autonomy argument in 1941 to promote an informal working group as in 1955 to refuse a European Postal and Telecommunication Community according to the institutional design of the European Coal and Steel Community. The very name of the European Conference of Postal and Telecommunications Administrations (CEPT), which emerged in 1959 out of long and protracted negotiations, heralded the administrative, not political, nature of the institution. In order to distance the CEPT from the European Economic Community and the Council of Europe, the founding agreement stated

  Germanisation or Europeanization of transborder communication networks, spaces and governance?This article has shown that the EPTU played an important role in the long-term development of European PTT governance and transnational spaces of communication in Europe. It was connected to interwar discussions of PTT issues and the founding of a new European PTT organisation. The EPTU for the first time implemented new institutional designs as well as standards for postal tariffs or telecommunication equipment, which were again put on the agenda after the war. A key vector for these continuities were transnational expert networks that functioned even under wartime conditions. Against this background, the interpretative framework suitable to understand the EPTU needs to be reflected on. Was the EPTU more about the Germanisation or Europeanization of transborder communication networks, spaces and governance? Many contemporaries criticized the EPTU for having been a German performance. If the EPTU-members debated on the normative and symbolical content of this Europe, in particular regarding the choice of official languages and currency for the Union, the outcome was so close to Germany's own regulation that some commentators contested its Europeanness. Again, the Swedish newspaper Dagens Nyheter pointed out for instance that "the Vienna agreement is solely built upon German rates and weight scales: one power rules59 Union européenne des Postes et Télécommunications, mémorandum préparé par le Secrétariat général, Assemblée consultative du Conseil de l'Europe, troisième session ordinaire, 26 November 1951, 4. 60 F., Risch, The Tasks and Aims of a European Postal Union, in: L'Union postale, 67 (1942) 9, 249. 61 "Discours de la « conférence des présidents » d'Aix-la-Chapelle". Pages, Haut Commissariat de la République française en Allemagne, to the French PTT minister, 2 February 1952, AN, 920257/1.

36

  Locke, General Post Office, to Armstrong, Foreign Office (draft), 27 July 1951, Royal Mail Archives, London, POST 122/506. 37 On long term evolutions in European PTT governance, see: C., Henrich-Franke, Continuities and Discontinuities in Infrastructure Governance in Postwar Europe, and L., Laborie, Enveloping Europe: Plans and Practices in Postal Governance, in: Contemporary European History (under review).

38 G., Albrecht, in: L'Union postale, 68, (1943) 4, 136-140. 39 Retirement of Mr. Charles de Forster, in: L'Union postale, 71, (1946) 7, 181.

Diverse correspondence of the Reichspostministerium with the Foreign Office in summer 1941, Bundesarchiv Berlin, R4701/11631.

Diverse correspondence of the Reichspostministerium with the Foreign Office concerning France, Bundesarchiv Berlin, R4701/11614.

Internal memorandum of the Reichspostministerium regarding French participation in the EPTU, undated, Bundesarchiv Berlin, R4701/116969.

leadership." 65 It was congruent with other attempts of this kind, but proved to be more successful than any other one. Why so? Maybe because a kind of pre-existing European pipe channelled it. Under the cloak of National Socialist Internationalism, the EPTU was able to sustain the traditional non-symbolic and informal working level cooperation. This turned out to be the factor of success for intensified and enlarged cooperation throughout 1943 -at a time when the Axis powers were beginning to fight rear-guard battles at the front.

On the other hand, if Europeanization is defined as a transnational dynamic that the actors leading, contesting, commenting on it claim to be 'European', then the EPTU is just about Europeanization. This is not only because of the organisation's name, but also because the people supporting as well as contesting it explicitly referred to the making of Europe in their arguments. Even the most sceptical contemporaries like Dagens Nyheter viewed the EPTU through the European lens. In the same article as quoted above the paper wrote: "We are, however, not used to such dealings with international affairs or to any group of powers that declares: This is Europe! Fortunately, Europe is too big for this". 66 From this perspective the EPTU can be referred to as a Europeanization event or engine -it propelled negotiations and discussions about the meaning of Europe.

In Vienna, some participants stressed the fact that tighter infrastructural links helped build Europe as a community. Politicians like the fascist Italian PTT minister Giovanni Host-Venturi in particular claimed that it would pave the way for a "new Europe" and foster a "true European solidarity". 67 Talking about Europe, the PTT minister of the Reich Wilhelm Ohnesorge left the congress satisfied, he said, "as a man who believes in this community of destiny with all the persuasion of his heart". 68 Experts too connected the EPTU with the larger issue of Europe and the European identity. Gunnar Albrecht expected that it would develop a "a feeling of brotherhood among the peoples of Europe". 69 Europe was not precisely but rather broadly defined in the convention. According to article 7, "any European country, or one bordering a European country" could join the EPTU. 70 Before war with the USSR broke out, Soviet delegates were invited to an exchange of views.

In fact, two sorts of Europe took shape in 1942 and 1943, one on the level of formal 65 M., Herren, 'Neither this Way nor any Other', (12 membership and another on the level of working relations. The formal one was in accordance with the national socialist internationalism, and encompassed a European space led by Germany and its allies. The informal one was surprisingly pan-European, including neutral countries, but also, at least in the EPTU's participants' mind, Great Britain and the Soviet Union. The notion of a spatially broad Europe was reinforced and became a strong argument in the debates about PTT integration after the war.

The Europeanization process which took place within and through the EPTU had three main characteristics. Firstly, it was vertical and top down: heads of PTT services gathered within a European institution were the leading forces. Secondly, it was direct: PTT services actually were the object of their policy. Thirdly, it was normative: it produced common standards towards which national norms would converge. In that respect, the EPTU blurred the difference between the national and the European level and was truly about integration and the emergence of a flat transnational communication area.

To conclude, the EPTU kept the idea of a PTT union alive and consolidated networks between experts as they proved to be stable even during the war, preparing together plans for peacetime Europe that would be part of post-war discussions. The EPTU even outlined pan-European postal and telecommunication standards that united European communication networks and spaces. Still, there is a lot more research to be done in order to be able to draw a much more detailed picture of the EPTU and to grasp the organisation's Europeanness.


Siham Amra

Thierry Bataille

Saliha Bourouina Bacha

Mustapha Bourouina

NANOSTRUCTURED MODIFIED CARBON PASTE ELECTRODE AS VOLTAMMETRIC SENSOR FOR ISOPROTURON TRACE ANALYSIS IN WATER

Keywords: Carbon Paste Electrode, nanostructured composite material, trace analysis, Isoproturon, cyclic voltammetry

A new electrochemical sensor based on nanostructured carbon paste electrodes (CPEs) is developed for the sensitive detection of Isoproturon in water. The CPEs were nanostructured by incorporation of carbon nanotubes (NTCs) and synthetized copper oxide nanoparticles (CuO). They were characterized using the X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and voltammetric methods. Electrochemical experiments showed that the adsorption of Isoproturon on to (GC-NTC-CuO)-CPE, associated with nanomaterials (NTCs and CuO), provided remarkable analytical performances of the sensor such as a large quantification range from 1 to 200 µg.L -1 with a detection limit of 0.1 µg.L -1 of Isoproturon and no interferences of some another pesticides tested (specificity of ISO adsorption in acidified water). The tests carried out on real samples of water are conclusive. The analytical performances of the sensor showed that it is suitable for the specific determination of pesticide traces in water.

INTRODUCTION

The use of pesticides, although necessary to protect crops and minimize losses, is detrimental to the ecosystem and human health by the pollution it generates. Because of their physicochemical properties, these compounds can migrate to groundwater and surface water and alter the quality of water and food. Among others, Isoproturon (ISO) is an herbicide of the substituted urea family, widely used in cereal agriculture to control weeds. It is a toxic product, likely to harm human health [1]. WHO recommends a threshold concentration of 9 µgL -1 of ISO for water quality [START_REF]Guidelines for Drinking-water Quality[END_REF]. In addition, the European Union has set its maximum allowable concentration at 0.1 μgL -1 in drinking water [START_REF] Johnson | [END_REF]. Many pesticide analysis techniques have been developed such as capillary electrophoresis [4, 5], chromatographic techniques [6, 7, 8-10] and chromatography coupled to mass spectroscopy. Although they are very sensitive and reliable but have strong drawbacks such as complex and long processing samples and can only be performed by highly qualified personnel. In this context, electrochemical based sensing devices are a promising alternative, offering great potentials for a broad range of analytical applications. These tools are very sensitive and reliable, selective, fast, inexpensive and are suitable for on-site analysis.

Most of the research developed in pesticides analysis has focused on enzymatic quantification [11-13], while current works are moving towards direct detection [14,15]. Moreover, the development of nanotechnology has paved the way for the manufacture of new, efficient and inexpensive electrode materials [16,17]. Indeed, electrochemical sensors have increasingly used nanoparticles because of their special properties that increase the surface area of electrodes, accelerate mass transport, control the microenvironment of electrodes and allow efficient catalysis [16,17]. The use of carbon, in its various forms (graphite, nanotubes, graphene, etc.), in the design of electrochemical sensors and biosensors is widespread [18][19][20].

In order to improve their properties, particularly the selectivity towards target analytes, nanostructured materials can be mixed with carbon-based materials. Furthermore, it is well documented that materials containing nanocomposites such as copper oxide (CuO), zinc oxide (ZnO), manganese oxide (MnO2) and others [21][22][23] are exploited in the detection of pesticides in order to interact specifically with the analyte and to facilitate the charge transfer.

The aim of this work is to develop a new sensor based on carbon paste consisting of a GC powder nanostructured by NTC and CuO in order to enhance the sensitive and selective Isoproturon analysis in aqueous solution using the CV method.

Materials and methods

Reagents and Materials

All reagents used are of analytical grade. Nujol (mineral oil), graphite powder (< 20µm), carbon nanotubes (DxL: 110-170 nm x 5-9µm), sulfuric acid (for analysis EMSURE, 98%), ethanol(99%), acetone, Isoproturon (analytical standard 99.9%) were purchased from Sigma-Aldrich, and ammonium carbonate (NH4)2CO3, copper sulphate pentahydrate CuSO4.5H2O, sodium hydroxide NaOH were provide by Prolabo. All aqueous solutions were prepared with deionized (DI) 18.2 M.cm (25 ºC) water from Millipore Direct-Q Water system.Stock solutions of Isoproturon (0.1M) were prepared with ethanol and subsequent dilutions were prepared daily with ultrapure water and stored at 4°C in the dark. Standard solutions of pesticides used as potential interferences of Isoproturon detection were prepared with deionized water and employed during the interference study. All experiments were performed at room temperature (20 ± 1°C).All reagents were used as received.

Instrumentation

X-ray powder pattern was collected with a Panalytical Empyrean powder diffractometer (θ-θ Bragg-Brentano geometry) working with the Cu Kα radiation (λ K1 = 1.5406 Å, λ K2 = 1.5444 Å) selected with a flat multilayer X-ray mirror (Bragg-Brentano HD ® ). Data were collected with a Pixel 1D silicon-strip detector, in the angular range 10-80° (2θ) (step size ~0.013° (2θ)). The surface morphology of the prepared samples was characterized by scanning electron microscope (JEOL JSM-7100F, Detector EDS Oxford Instrument 50 mm 2 ). All electrochemical experiments were performed with a PGSTAT20 Metrohm potentiostat/galvanostat in combination with the NOVA 2.1 software, at room temperature, using a traditional three-electrode electrochemical cell with a working electrode, Ag/AgCl (3 M KCl) as reference electrode, and a platinum wire counter electrode.

CuO nanoparticles synthesis

The CuO nanoparticles were synthesized by the hydrothermal method described by M. Ben Ali et al [23]. 10 mL of a freshly prepared solution of copper sulfate 1 mol L -1 (CuSO4.5H2O) was added dropwise to a stirred solution of 5 mL of 1M ammonium carbonate solution in 35 mL of deionized water. Then, 1 mol L -1 sodium hydroxide aqueous solution was added dropwise to the previous mixture to form a white precipitate at pH=11. After 30 minutes of magnetic stirring, the mixture was transferred to a teflon-coated stainless steel autoclave of 45 mL capacity for 16 hours at 160 ° C. The nanoparticles obtained were washed and then dried at 90 ° C. for 24 hours. The powder obtained was then calcined at 600 ° C for 4 hours.

Preparation of the CPEs

The carbon pastes (CPs) have been prepared by mixing the components in desired proportions with a binder (Nujol) for about thirty minutes to have a homogeneous mixture. The resulting paste was then packed into the cavity (2 mm deep) at the end of homemade Teflon cylindrical tube of 3 mm (internal diameter) surrounding hermetically a graphite bar acting as electrical contact. The surface was smoothed off by rubbing the electrode several times slowly across a paper. Four CPs of different compositions were prepared: and composed in mass % of (i) graphite powder (85%) and binder (15%) (GC-CP), (ii) graphite powder (60%), binder (15%) and carbon nanotubes (25%) (GC_NTC)-CP), (iii) graphite powder (60%), binder (15%) and nanoparticles of copper oxide (25%) ((GC-CuO)-CP) and (iv) graphite powder (60%), binder (15%), carbon nanotubes (10%) and copper oxide nanoparticles (15%) ((GC-NTC-CuO)-CP. The percentage of added blinder was previously optimized and the value of 15% allowed maintaining the compacted pastes in the electrode cavity while retraining its electrical properties. In order to compare the different nanostructured pastes the proportion of graphic powder was kept at 60%. The morphology of the components of the CPs was studied by scanning electron microscopy and in the mixture for (GC-NTC-CuO)-CP (see Figure 2). The synthetized CuO material (SEM image (C)) shows as clusters of roughly spherical particles at sub-micrometric sizes. In the SEM image (A) graphite carbon appears as particles of graphite sheets with dispersed sizes lower than 20 µm. In the SEM image (B) the carbon nanotubes are looking tangled. For (GC-NTC-CuO)_CP, SEM image (D) clearly shows that the paste is composed of a mixture of GC, CNTs and CuO nanoparticles closely linked insuring electrical contact between all the components in (GC-NTC-CuO)-CP. It can also be seen that this mixture gives a very rough and spongy surface of the CP which could provide a large contact area for subsequent interaction with the analyzed pesticides.

10.1002/elan.201900083

Accepted Manuscript

Effect of the paste composition on CPE response of Isoproturon

The electrochemical behavior of Isoproturon (ISO) on different CPEs was investigated by CV. Figure 3 presented the CVs of the GC-CPE (curve 1), (GC-NTC)-CPE (curve 2), (GC-CuO)-CPE (curve 3) and (GC-NTC-CuO)-CPE (curve 4) in 0.5mol L -1 H2SO4 electrolyte solution in the presence of 10 -4 mol L -1 of Isoproturon. This electrolyte with a pH about 1, was the optimized composition given a quasi-rapid electron transfer (well defined peak) with an optimum current intensity.

As can be seen, all the recorded voltammograms show an oxidation peak around 1.0 V of variable intensity without reduction peak at the reverse scan (non-reversible electrochemical system). The current response depends on the composition of the paste. Indeed, the most intense current intensities were recorded when CuO nanoparticles were incorporated in the CPE, indicating that adsorption of ISO is favored by CuO. In addition, by comparison of curve 1 and 2, we can observe a significant increase in the oxidation current due to the presence of NTC in the paste. This enhancement of sensitivity is probably brought out by the increase of the specific active surface of the electrode and by the paste nanostructuration, which improves the electrical contact of the powder material and facilitates the charge transfer. This effect of the NTCs was also observed for CPEs integrating CuO nanoparticles (curve 3 and 4). The best response is thereby obtained by (CG-NTC-CuO)-CPE with a gain of about 30 in sensitivity in comparison with classical CP-CPE. The peak shape in CV (in particularly with the presence of CuO nanoparticles in the paste) is characteristic of the oxidation of adsorbed Isoproturon on electrode material (see figure 3).

A first study for a large range of 3 Isoproturon concentrations (10 -6 , 10 -5 and 10 -4 mol L -1 ) indicates a good linearity of the peak current versus concentration in this 3 decades range (insert on figure 4).The best sensitivity is recorded for the (CG-NTC-CuO)-CPE indicating the promising use of nanostructured materials for the sensitive voltammetric detection of Isoproturon. Accepted Manuscript

Influence of the scan rate in CV

The effect of the potential scan rate on the CV peak currents for a solution of Isoproturon 5.10 - 7 mol L -1 in H2SO4 (0.5 mol L -1 ) was examined over the range of 5-40 mVs -1 , upper scan rates implicates CV distortion due to the ohmic drop and greater capacitive currents. As displayed by the figure 5, the voltammograms (only the forward scan presented) present the same shape for the oxidation of the Isoproturon with an increasing of the capacitive current. The variation of the anodic peak currents (Ip) as a function of the scan rates (v) (figure 5) shows linear relation(r 2 =0.999)in this scan rate range indicating that the process at the electrode is not controlled by the diffusion of Isoproturon but by the oxidation of a quantity of Isoproturon on the electrode surface. This suggests an adsorption step of Isoproturon before its oxidation on the electrode (typical electrochemical behavior of thin layer adsorbed compounds [25]).

Effect of pre-concentration time

Since the detection of Isoproturon trace levels depends on its adsorption on CPE, the waiting time before the analysis in CV can significantly affect the current intensity of ISO oxidation. Figure 6 exhibits the effect of the adsorption time under magnetic stirring (300 rpm) before the CV analysis on the sensor response for an Isoproturon concentration of 10 -6 mol L -1 in solution.

The current intensity of the oxidation peak increases in function of the adsorption time, and reaches a maximum after 12 minutes (no change for the current intensity at 12 and 17 minutes) indicating the obtain of adsorption equilibria of Isoproturon at (CG-NTC-CuO)-CPE. It is near the same for lower concentrations than 10 -6 mol L -1 .

10.1002/elan.201900083 [ISO] = 10 -6 mol L -1 , v= 10 mV s -1

Accepted Manuscript

Sensor application to Isoproturon analysis

Performances of the (CG-NTC-CuO)-CPE sensor

The calibration of the CG-NTC-CuO sensor was investigated using cyclic voltammetry, under optimized conditions (potential range: 0.65-1.1 V; sweep rate 10 mV.s -1 ; waiting time 12 min under stirring H2SO4 (0.5 mol L -1 ) as the supporting electrolyte). Figure 7 shows a well-defined peak with an oxidation current linearly proportional to the concentration of Isoproturon, in the concentration range of 10 -8 -10 -6 mol L -1 (r 2 =0.998). The detection and quantification limits, calculated as the concentration of ISO that gave a signal equal to respectively three and ten times the standard deviation of the background current, were found to be in the nano-molar level respectively 5 10 -10 mol L -1 and 1.5 10 -9 mol L -1 .

The interference study of the Isoproturon CG-NTC-CuO sensor was carried out by comparing the current response for 5.10 -5 mol L -1 of Isoproturon in 0.5 mol L -1 sulfuric acid solution before and after adding some potential interfering pesticide such some class of phenyl urea herbicides (linuron), other herbicides (propazine, tetrazineand metazachlore) and chlordecone at 5.10 -5 mol L -1 concentrations. The results showed negligible interferences of these substances (lower than 2% on the value of oxidation peak current) and indicated that this sensor is specific to the detection of Isoproturon.

Table 1 shows the comparison of the analytical performance of GC-NTC-CuO carbon paste sensor with other reported sensors or analytical methods in the literature. The voltammetric results from this work present a good linearity range and low detection limit for ISO. These observed analytical results indicate that the proposed electrochemical sensor seems to be attractive and suitable for trace analysis of ISO. Accepted Manuscript

Repeatability and reproducibility study

Repeatability and reproducibility are important criteria for any developed sensor. Therefore, the repeatability and reproducibility of the designed sensor for determination of Isoproturon were studied using four concentrations (1, 3, 7, and 9.10 -8 mol L -1 ). This was evaluated by CV by performing three determinations of peak current intensity with the same standard solutions of Isoproturon. The results are summarized in Table 2.

The repeatability of the (CG-CuO-NTC)-CPE was evaluated by using the same electrode in the optimal conditions for CV experiments. It appears that the relative standard deviations (RSD) did not exceed 3.6%.The reproducibility was estimated by using three modified electrodes independently prepared by the same procedure. In this case, the RSD of peak current intensities for ISO oxidation did not exceed 6.3%. Table2: Study of repeatability and reproducibility for the proposed CV method with (CG-NTC-CuO)-CPE in the Isoproturon concentration range of 10 -8 -10 -7 mol L -1

Application to real samples

To illustrate the practical application of (CG-CuO-NTC)-CPE, the electrode was applied to Isoproturon detection in local tap water. As the voltammograms in CV of acidified tap water (0.1 mol L -1 H2SO4) did not give an observable peak in the potential window corresponding to ISO oxidation (< 0.1µg L -1 ), two tap water samples were spiked at 0.2 .and 0.6 µmol L -1 . Voltammetric studies under the optimum experimental conditions were carried out to determinate ISO in these water samples. The standard addition method was used for the quantification of ISO in these spiked samples and three replicates were done. The presented data in Table 3 show excellent recovery rates that are in the 96.4 -101.7 range with RSD < 4%. This indicates that the proposed method with (CG-CuO-NTC)-CPE was successfully applied for determination of Isoproturon in tap water samples as indicated.

Conclusion

In this present work, an electrochemical sensor was developed for ISO detection in water. It consists of a carbon paste mixed with nano-materials (NTCs and CuO) in order to produce a nanostructured sensitive surface of the CPE. The CV method was used to detect ISO following the measurement of the oxidation peak current at Ep = 0.89 V/Ag/AgCl. This sensor is characterized by a wide concentration range, a good sensitivity and a low detection limit due to the adsorption of ISO onto this nanostructured carbon paste. The tests carried out on contaminated real samples of water are conclusive, thus the developed sensor could be used for the trace detection of ISO in water as a sensitive, selective and inexpensive device.

1

 1 Figure 1 shows the collected X-ray powder diffraction pattern of the synthesized CuO. Dirac peaks below the pattern indicate the positions of the reflexions of CuO tenorite from the ICDD PDF-2 database. Nor additional diffraction line neither angular shift are observed, which clearly indicates the purity of the crystallized compound.

Figure 1 :

 1 Figure 1: XRD pattern of the synthesized CuO powder (red) compared to the theoretical pattern of CuO tenorite (blue)

Figure 2 : 3 . 2

 232 Figure 2: SEM images of the various compoundsused for the CPEs preparation, CG (A), NTC (B), CuO (C) and constituent mixtures (CG-NTC-CuO )-CP (D)3.2 Cyclic voltammetric studies at CPEs

Figure 3 :

 3 Figure 3: Cyclic voltammetry obtained with the (GC)-CPE (A), (CG-CNT)-CPE (B), (CG-CuO)-CPE (C) and (CG-NTC-CuO)-CPE (D) for 10 -4 mol L -1 ISO in H2SO4 solution (0.5 mol L -1 ) with scan rate of 10 mV s -1

Figure 4 :

 4 Figure 4: variation of current intensity as a function of the ISO concentration (10 -6 , 10 -5 and 10 -4 mol L -1 ), for the different paste electrodes (CG-NTC)-CPE (A), (CG-CuO)-CPE (B) and (CG-NTC-CuO)-CPE(C)in H2SO4 solution (0.5 mol L -1 ) with scan rate of 10 mV s -1

Figure 5 :

 5 Figure 5: Cyclic voltammetry for different potential scan rates at the (CG-NTC-CuO)-CPE electrode in 0.5 mol L -1 H2SO4 for [iso] = 5.10 -7 mol L -1 .Insert: oxidation peak current in function of scan rate

Figure 6 :

 6 Figure 6: Influence of the adsorption time under stirring on the peak current intensity obtained in CV for Isoproturon oxidation at (CG-NTC-CuO)-CPE in H2SO4 (0.5 mol L -1 ), [ISO] = 10 -6 mol L -1 , v= 10 mV s -1

Figure 7 :

 7 Figure 7: Cyclic voltammograms at (CG-NTC-CuO)-CPE in 0.5mol L -1 H2SO4 (v=0.01V s -1 ) and Calibration curves for different Isoproturon concentrations from 10 -8 to 10 -6 mol L -1

Table 1 :

 1 Comparison with subsequent works 10.1002/elan.201900083

  These results indicate that the proposed sensor has good repeatability and reproducibility.

	Concentration	Repeatability of Ip values	Reproducibility of Ip values
	of Isoproturon
	(×10 -8 mol L -1 )	RSD* (%)	RSD* (%)
	1	2.1	3.4
	3	3.6	5.1
	7	3.6	5.7
	9	2.0	6.3
	* (n= 3)

Table 3 :

 3 Analysis of two tap water samples spiked with Isoproturon by applying CV method with (CG-NTC-CuO)-CPE. Standard addition determination for 3 replicates

	10.1002/elan.201900083

Acknowledgements

Gratefully acknowledgements to the Algerian Ministry of higher education and scientific research for their financial supports; FEDER, Région Bretagne and Rennes Métropole for their contribution to the purchase of the in-situ X-ray powder diffractometer and CMEBA center of ISCR-CNRS 6226 for the MEB analysis.