mercredi 15 décembre 2021

Obituary: Christian Ducauze

 Christian Ducauze (June 15, 1943, Sainte-Livrade-sur-Lot - August 22, 2021, Paris), a life of teaching analytical chemistry

Hervé This,
International Center for Molecular Gastronomy INRAE-AgroParisTech.

The card that friends of Christian Ducauze sent to his widow on the occasion of his death showed an Asian master handing a book to a student. A representation of North Africa would also have been appropriate, as Christian Ducauze began his career with several years in Tunis, but it did emphasize one of the main aspects of his career, dedicated to transmission. Unfortunately we did not find a card that would expression that, for Christian Ducauze as for us, chemistry is a central science, essential - he repeated - for the initiation of agronomy students to the handling of complex systems, such as those found in food and the environment.

From Strasbourg to Tunis, then to Paris

Christian Ducauze was proud to owe his training as a chemist to the École Nationale Supérieure de Chimie in Strasbourg, starting in 1963. Graduating as a chemical engineer in 1966, he continued his training with a Master's degree in electrochemistry, then with a PhD at the CEA, still in Strasbourg, during which he developed an electroanalysis method -differential oscillographic voltammetry- for the determination of trace elements in solution (cadmium and copper in particular).
In 1970, he left France to do his military service as an Assistant Professor at the National Agronomic Institute of Tunisia, which, created in 1898, is the oldest school of agronomy in Africa. He stayed there for six years, learning the profession of professor and laboratory director, as well as the implementation of statistical methods for the determination of traces of magnesium. It was in Tunis that he met Larbi Bouguerra, a specialist in environmental chemistry, who became one of his friends.
In 1976, he passed the competitive examination to become a professor of analytical chemistry at what was then the Institut National Agronomique Paris-Grignon (INA-PG): among the friends who helped him for the preparation of his selection lesson were Jean-Yves Le Déaut, assistant professor of biochemistry at the University Louis Pasteur in Strasbourg, whom he had known in Tunis, where he was also teaching, and who would shortly afterwards become president of the Parliamentary Office for the Evaluation of Scientific and Technological Choices, but also Charles Kappenstein (today professor emeritus at Poitiers, who had shared Christian Ducauze's office at the end of the 1960's on the 10th floor of the "Chemistry Tower", in Strasbourg).
Christian Ducauze knew very well that he was arriving in a « grande école » (i.e., a university with a strong selection) that, from its inception, had been teaching analytical chemistry at the highest level: the first « Institut National Agronomique », created in Versailles in 1848, included a chair of general chemistry and analysis, whose incumbent was Charles Adolphe Würtz, member of the French academy of sciences, Dean of the faculty of medicine, and professor at the Sorbonne. After the second Institut National Agronomique was transferred in 1890 to 16 rue Claude Bernard, the chemistry professorships went to Émile Péligot, Jean-Baptiste Boussingault, Achille Müntz,  Antoine-Charles Girard, Maurice Lemoigne, most of them members of the French Academy of sciences or of the French Academy of agriculture.
So many great names! However, when Christian Ducauze arrived at what had become INA P-G, there were above all the premises and the wish of the Institute's administration to see chemistry well taught, but no research laboratory, no competent personnel, and no equipment: Christian Ducauze inherited only a pH-meter and a UV-visible spectrometer, moreover without a recorder. Everything had to be done, while the financial means could only be obtained if a certain level of credibility was first achieved.
However, Christian Ducauze was active and found support from the Ministry of the Environment, the CNRS, the Compagnie Générale des Eaux and, finally, the Ministry of Research, while he created original teaching programs to adapt a course of analytical chemistry to the very specific training needs of agricultural students, different from those of students in chemistry schools or university analytical chemistry departments.
In 1978, having understood the importance of continuing education, he organized advanced training sessions entitled "Current techniques in the service of chemical analysis": these three-day courses were oriented, the first towards elementary analysis and the second towards structural organic analysis. At the time, this continuing education activity was both a source of income for the laboratory and a showcase for the strengths of the teaching and research, but it was also an opportunity to measure, with engineers from the public and private sectors, the adequacy of the teaching to the problems that agricultural engineers would soon encounter. It was also an opportunity to see the considerable national needs for training in analytical chemistry, as the universities had not fully met these needs.
The European School of Analytical Chemistry (EECA) was therefore created with, at its head, an international scientific committee of about forty members, chaired by Christian Ducauze, to define the major training programs. Five disciplinary fields were considered: separative methods (all chromatography and capillary electrophoresis); spectrometric methods (essentially atomic absorption spectroscopy and nuclear magnetic resonance); quality, data processing and management (chemometrics, quality assurance, etc.); sensory analysis (all aspects); specific applications (characterization of materials, environment, food, pharmaceutical products, etc.). The success of the EECA is then attested by numerous requests from industry, in particular the food industry, and also by the European Economic Community, which entrusts training courses to help the scientific and technological development of Eastern European countries.
Then, from 1982, the co-habilitation for a new master program, followed by the educational reform set up at the INA P-G, obliged to rethink the whole training in analytical chemistry at the School, so that this time a training of engineers by apprenticeship and a tutoring of students of this new training were set up.

The birth of French chemometrics

Statistical methods were used in many of the laboratory's research projects, and a new discipline was soon created, called "chemometrics", which is now defined as the use of statistical methods to process chemical analysis data. It allows to re-analyze the notion of analytical chemistry, which will be, much later, the subject of a reference book published by Lavoisier Tec et Doc (C. Ducauze, Chimie analytique, analyse chimique et chimiométrie). The development of these methods has been fundamental for both research and teaching (Rutledge and Ducauze, 1991; Ducauze and Bermond, 1992; Eveleigh, 1994; etc.).
The idea of chemometrics has led to renovations in laboratory practices and quality assurance, providing effective tools to deal with a wide variety of applications: studies of animal products (Gerbanowski et al., 1997) or plants (Maalouly et al., 2004), analytical methodology and valorization of chemical analysis data (Feinberg et al., 1991; Guesnier et al., 1993; Hernandez et al. 1994), etc. These contributions led the European Economic Community to provide financial support to the Analytical Chemistry Laboratory in the framework of a European project for the teaching of chemometrics: Applied information technology for the chemical, pharmaceutical and agrofood industry (COMETT project - leader: D.L. Massart, VUB, Belgium).
For research at the Analytical Chemistry Laboratory of INA P-G, new application topics were chosen, with, obviously, overlaps between fields.
First of all, the analytical studies of metals (lead, cadmium, mercury, in particular) concerned various matrices, such as soils or waters, for example (in particular with Alain Bermond, then Valérie Camel and Nastaran Manoucheri), notably with the support of the Ministry of the Environment: speciation of mercury (Ireland-Ripert et al,  1982; Ireland-Ripert, 1982; Besson, 1981), modelling of pollution (Godin et al., 1985), migration towards the water table and passage in plants (Feinberg et al., 1987; Heuillet et al., 1988; Heuillet et al., 1988)...
In this field of the environment, the media imposed the implementation of analytical techniques different from atomic absorption or electrochemistry: HPLC (El Din et al., 1984), GC-MS, infrared spectroscopy (Maalouly et al., 2004), fluorescence spectroscopy ... always in the various media (Jarret et al., 1985; Jan et al., 1988; Jarret et al., 1983):
At the same time, environmental concerns led to studies of agri-food matrices, first for metals, but then for many other compounds. Initially, the complexity of the matrices to be analyzed led to an interest in the problem of sample preparation and, initially, the laboratory developed a rapid and efficient high-temperature calcination method for the determination of lead, cadmium and copper in foods (Feinberg and Ducauze, 1980). For the same reason, it was necessary at the same time to learn how to control the interferences occurring at the time of measurement (Feinberg and Ducauze, Analusis, 1980). Overcoming these difficulties again required the use of statistical methods. And we should not forget the studies of wines, with works often presented at the congresses In Vino Analytica Sciencia (Cheynier et al., 1983; Rutledge et al., 1993; Belaiche et al., 1996; Delgadillo et al., 2001; Delgadillo, 2004), as well as the studies of glycation reactions (Birlouez-Aragon et al., 2004)

The international influence

When the laboratory was attached to the Food Industry Sector of INRA (Department of Consumer Sciences), in 1984, Christian Ducauze wanted to find a better balance of research activities between the environmental and food industry fields. As early as 1986, a team from the laboratory sought to reduce the time needed to prepare samples by implementing low resolution impulse nuclear magnetic resonance (IR-NMR). This method was already used in the fat industry, but its considerable potential had been little explored. The NMR-IBR allowed, at first, to develop fast control methods, useful in margarine industry (Rutledge et al., 1988; El Khaloui et al., 1990). This initial work led the laboratory, and in particular Douglas Rutledge, to be invited to join the Coordinating Committee of Concerted Action No. 1 of the FLAIR program. Having acquired a good command of the apparatus, the team then embarked on more difficult studies on the states and dynamics of water in food (Monteiro-Marques et al., 1991; Monteiro Marques et al., 2007),
Christian Ducauze was well aware that NMR was an essential tool for chemical analysis: was he not close to Gérard and Maryonne Martin, who had invented the SNIF-RMN natural isotope fractionation method, at the University of Nantes, to verify the origin and purity of many foods and beverages, in cases where traditional analytical methods fail to detect counterfeits? These relationships continued with Eurofins, the company created in 1987 by Gilles Martin, the inventors' son.
And, above all, all this research, with the use of NMR or other analytical techniques, was widely disseminated: by the EECA, as we have seen, but also by the international journal of analytical chemistry Analusis , of which Christian Ducauze was editor-in-chief for several years, and by the participation in various European working groups (Working Party on Food Chemistry and Division of Analytical Chemistry of the Federation of the European Chemical Societies, now EuChemS), where he created relationships with foreign universities and colleagues. Through these relationships with colleagues from all over the world, students came in great numbers: from 25 countries! Moreover, the Analytical Chemistry Laboratory organized international scientific conferences such as EuroAnalysis, EuroFoodChem, GAMS, In Vino Analytica Scientia...
But to enumerate, one risks to forget some actions, so much they were numerous! How can we not mention the theses that Christian Ducauze personally directed, in relation with Lebanon, Vietnam? How can we forget the joint teaching activities with the University of Nantes, where analytical chemistry was already present, but where the INA-PG team was important for the chemometric contributions? How can we forget the master "Research and development in analytical strategy", which was born from the collaboration with Arlette Baillet, at the Faculty of Pharmacy of Chatenay-Malabry?

Strategic analyses

As we have seen, Christian Ducauze has constantly sought to adapt the development of the laboratory to training needs, taking into account the pedagogical reform carried out at the INA P-G. The latter led him to examine in greater depth the specificity of the agricultural engineer and to conclude that his essential characteristic was his ability to apprehend problems at different scales: molecular, organized being, macro-system (economy, environment).
For the first two, the teaching that had been created responded well to this training objective, whether it was the atomic and molecular approach or the study of agri-food matrices and complex environments. On the other hand, macro-systems were less studied. In addition to the first and third year options introduced by Alain Bermond in the field of the environment, a need was felt, through quality control, on production in the field of the agro-food industries. In 1990, Christian Ducauze predicted that, in the future, the industrial control laboratory would no longer be considered as a means of repression, but would become the real pilot of the production units. In retrospect, we can see that the question of "control" in companies is complex, but that, in any case, the questions of regulations, in relation to analysis, have become essential, so much so that the industry has understood that sanitary errors must be absolutely avoided.
Christian Ducauze had other "political" convictions: he was convinced that the acceptance of an innovation by society is the condition for its diffusion. Innovation in agriculture illustrates the increasing divorce between the perception of citizens and the word of scientists. He was convinced that it was necessary to better organize the debate between the scientific world, the political world and the citizens: it seemed to him to be essential "to imagine new means, methods and places of debate to train and inform the public in a transparent way".
He analyzed that one of the worrying evolutions of our society was based on the increasingly marked confusion between what comes from a rigorous scientific approach and what comes from beliefs or manipulations. He was convinced that in the field of agriculture, innovation can give society a vision for the future and shed light on the issues of tomorrow. He participated in the establishment of this dialogue by transmitting his knowledge. And this is how he had ongoing discussions, notably with Jean-Yves Le Déaut, or with the journalist Olivier Lesgourgues, known in particular to science lovers on M6.
To conclude, I can testify, on the basis of numerous discussions with Christian Ducauze, that his actions in what became AgroParisTech from the National Agronomic Institute, did not forget that the School was born with an essential place for chemistry, born of the needs of agronomy at the time of the founders: for Würtz or Boussaingault, as for Justus von Liebig and many of his students, the question of synthetic fertilizers was of prime importance. Today, at a time when questions of sustainability, the environment, food safety (particularly with molecular biology methods), food safety and nutrition are being raised, knowledge of chemistry, its contribution and its dissemination have never been so essential.

This tribute to Christian Ducauze benefited from the testimonies of Douglas Rutledge and Luc Eveleigh, Jean-Yves Le Déaut, Charles Kappenstein.

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