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International audience; This paper presents a simple, accurate and multi-sample method for the determination of proline in wines thanks to a 96-well microplate technique. Praline is the most abundant amino acid in wine and is an important parameter related to wine characteristics or maturation processes of grape. In the current study, an improved application of the general method based on sodium hypochlorite oxidation and o-phthaldialdehyde (OPA)-thiol spectrofluorometric detection is described. The main interfering compounds for specific proline detection in wines are strongly reduced by selective reaction with OPA in a preliminary step under well-defined pH conditions. Application of the protocol after a 500-fold dilution of wine samples provides a working range between 0.02 and 2.90 g L-1, with a limit of detection of 7.50 mg L-1. Comparison and validation on real wine samples by ion-exchange chromatography prove that this procedure yields accurate results. Simplicity of the protocol used, with no need for centrifugation or filtration, organic solvents or high temperature enables its full implementation in plastic microplates and efficient application for routine analysis of proline in wines. (C) 2013 Elsevier Ltd. All rights reserved.

In the Mediterranean area, surface waters often have low discharge or renewal rates, hence metal contamination from industrialised catchments can have a high negative impact on the physico-chemical and biological water quality. In a context of climate and anthropological changes, it is necessary to provide an integrative approach for the prevention and control of metal pollution, in order to limit its impact on water resources, biodiversity, trophic network and human health. For this purpose, introduction of constructed wetlands (CWs) between natural aquatic ecosystems and industrialised zones or catchments is a promising strategy for eco-remediation. Analysis of the literature has shown that further research must be done to improve CW design, selection and management of wetland plant species and catchment organisation, in order to ensure the effectiveness of CWs in Mediterranean environments. Firstly, the parameters of basin design that have the greatest influence on metal removal processes must be identified, in order to better focus rhizospheric processes on specific purification objectives. We have summarised in a single diagram the relationships between the design parameters of a CW basin and the physico-chemical and biological processes of metal removal, on the basis of 21 mutually consistent papers. Secondly, in order to optimise the selection and distribution of helophytes in CWs, it is necessary to identify criteria of choice for the plant species that will best fit the remediation objectives and environmental and economic constraints. We have analysed the factors determining plant metal uptake efficiency in CWs on the basis of a qualitative meta-analysis of 13 studies with a view to determine whether the part played by metal uptake by plants is relevant in comparison with the other removal processes. Thirdly, we analysed the parameters to consider for establishing suitable management strategies for CWs and how they affect the whole CW design process. Finally, we propose monitoring and policy measures to facilitate the integration of CWs within Mediterranean industrialised catchments. Keywords: Constructed wetlands, Metal pollution, Plant species selection, Design methodologies, Management strategies, Industrialized Mediterranean Catchments

The aim of this paper was to study the reaction pathway of the biodegradation and photodegradation of Linear Alkylbenzene Sulphonates (LAS), and to propose an analytical method, faster and more reliable, to predict the evolution of LAS in a sewage treatment plant. For this purpose, a 20mgL−1 LAS solution was treated on the one hand by a conventional biodegradation method using microorganisms, taken directly from aeration tanks of a sludge treatment plant, and on the other hand by UV radiation. This second method allows a rapid determination of LAS and its by-products by means of a UV signal treatment. This alternative method seems thus to be more suitable for on-line analysis.

International audience; The degradation of 4-chlorophenol (4-CP) by electrochemical oxidation in the presence of carbon black (CB) was studied in a laboratory reactor. This reactor consisted of a stack of Ti/Pt electrodes. After the mixing of the solution to be treated with CB, the slurry electrode thus obtained flows through the electrode grids. The reaction pathways and kinetics were studied by means of high performance liquid chromatography coupled with a UV detection, ionic chromatography coupled with a conductimetric detection and gaseous chromatography coupled with mass spectrometry. The reaction pathways were thus determined: after the C–Cl bond breaking, phenol and chloride ions were detected in the solution. The formation of 2-chlorophenol was also detected. The influence of the amount of CB used on the degradation yield of 4-CP was also studied. The full mineralization of 4-CP could be reached if CB was present in a sufficient amount and, in this case, no chlorine was detected.

International audience; Water disinfection technologies based on ultraviolet (UV) radiations emitted by Light-Emitting Diodes (LED), as a wastewater tertiary treatment, have been shown to be promising for water reuse. Here, we assessed the fate of two ubiquitous pollutants, carbamazepine and anthracene, in soil watered with either UV-LED treated wastewaters or irrigation water. After 3 months, anthracene and carbamazepine were transformed two and three times faster respectively, in soils watered with UV-LED wastewater than in soils watered with tap water (probably because of the addition of organic matter by the effluent). Laccase activity was induced in the presence of the pollutants and anthraquinone was found as anthracene product of oxidation by laccases. Moreover, the addition of these pollutants into soil did not affect the functional diversity of autochthonous microbial communities assessed by Ecolog plates. Cellulase, protease and urease activities increased in soils watered with UV-LED treated wastewaters (UV-LED WW), showing transformation of organic matter from the effluent and lipase activity increased by anthracene addition, confirming the potential role of these enzymes as indicators of hydrocarbon contamination.

International audience; Soil microbial activity Faecal indicator Catabolic activity Enzymatic activities a b s t r a c t Advanced oxidation processes based on UV radiations have been shown to be a promising wastewater disinfection technology. The UV-LED system involves innovative materials and could be an advantageous alternative to mercury-vapor lamps. The use of the UV-LED system results in good water quality meeting the legislative requirements relating to wastewater reuse for irrigation. The aim of this study was to investigate the impact of watering with UV-LED treated wastewaters (UV-LED WW) on soil parameters. Solid-state 13 C NMR shows that watering with UV-LED WW do not change the chemical composition of soil organic matter compared to soil watered with potable water. Regarding microbiological parameters, laccase, cellulase, protease and urease activities increase in soils watered with UV-LED WW which means that organic matter brought by the effluent is actively degraded by soil microorganisms. The functional diversity of soil microorganisms is not affected by watering with UV-LED WW when it is altered by 4 and 8 months of watering with wastewater (WW). After 12 months, functional diversity is similar regardless of the water used for watering. The persistence of faecal indicator bacteria (coliform and enterococci) was also determined and watering with UV-LED WW does not increase their number nor their diversity unlike soils irrigated with activated sludge wastewater. The study of watering-soil microcosms with UV-LED WW indicates that this system seems to be a promising alternative to the UV-lamp-treated wastewaters. ª

International audience; The electrochemical oxidation of an aqueous phenol solution was studied via a novel process. Experiments were conducted by recirculating a slurry electrode made of the product to be treated (phenol) and a catalyst (carbon black) through a flow-by electrolyser with a vertical stack of perforated Ti/Pt electrodes. Both the capacity of high adsorption of organic compounds and gases and the conductivity properties of Carbon Black allowed the acceleration of the degradation. High pressure liquid chromatography (HPLC) analysis was used to follow phenol loss and the formation of by-products. Gas chromatography (GC) analysis revealed the presence of two gases: oxygen-electrogenerated by the oxidation of water- and carbon dioxide produced by both phenol and CB oxidation. Other experiments under nitrogen and oxygen flow were performed in a closed reactor cell and proved that oxygen generated by Ti/Pt electrodes is sufficient to obtain the full degradation of phenol. The effects of CB concentration (ranging from 0 to 4 g l−1), of the nature of CB and of the applied current (from 0 to 20 A) were investigated. An increase of CB concentration and applied current was found to shift product distribution to favour the formation of carbon dioxide. A removal efficiency of 100% was obtained in a reaction time of 15 min under the following conditions: an initial phenol concentration of 1 mmol l−1, 4 g l−1 of CB, an applied current of 10 A, a flow rate of 10 ml s−1 and a temperature of 30°C.

International audience; Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO 2 .

International audience; Despite evidence of formation of brominated compounds in seawater swimming pools treated with chlorine, no data about exposure levels to these compounds have been reported. To address this issue, a survey has been carried out in four establishments (representing 8 pools) fed with seawater and devoted to relaxing and cure treatments (thalassotherapy centres located in Southeast of France). Carcinogenic and mutagenic brominated disinfection byproducts (trihalomethanes -THM- and halogenated acetic acids -HAA-) were quantified at varying levels, statistically related to organic loadings brought by bathers, and not from marine organic matter, and also linked to activities carried out in the pools (watergym vs swimming). Bromoform and dibromoacetic acid, the most abundant THM and HAA detected, were measured at levels up to 18-fold greater than the maximum contaminant levels of 60 and 80 mu g/L fixed by US.EPA in drinking waters. The correlations between these disinfection byproducts and other environmental factors such as nitrogen, pH, temperature, free residual chlorine, UV254, chloride and bromide concentrations, and daily frequentation were examined. Because thalassotherapy and seawater swimming pools (hotels, cruise ships, ...) are increasing in use around the world and because carcinogenic and mutagenic brominated byproducts may be produced in chlorinated seawater swimming pools, specific care should be taken to assure cleanliness of users (swimmers and patients taking the waters) and to increase water circulation through media filters to reduce levels of brominated byproducts. (C) 2011 Elsevier Ltd. All rights reserved.

International audience; The development of new technologies for water recycling is a priority for arid and semi-arid countries such as those of the Mediterranean basin. The aim of this study was to test the efficiency of UV-A and UV-C light emitting diodes (UV-LEDs) on bacteria inactivation. We used Escherichia coli and Enterococcus faecalis, bioin-dicators of fecal pollution typically found in urban wastewaters. An experimental design was performed to discriminate weight of factors influencing bacteria inactivation yields and reactivation phenomena. Four parameters were tested on simple bacterial cultures: pH, bacterial density, exposure time and wavelength. It appears that the exposure time and wavelength used have a significant effect on the response. The 280/ 365 nm or 280/405 nm coupled wavelengths, have the most important bactericidal effect, and we also note the absence of bacterial reactivation after 60 s of exposure to UV.

International audience; This paper presents a simple, accurate and multi-sample method for the determination of volatile fatty acids (VFAs) thanks to a 96-well microplate technique. A procedure using an activating reagent of the carboxylic function (water-soluble carbodiimide EDC) and a fluorescent amino labeling reagent (N-(1-naphthyl)ethylenediamine, EDAN) allows the formation of an isoindole derivative that needs to be separated from initial fluorescent amine for efficient VFAs determination. Isolation of these fluorescent VFA-derivatives was carried out by use of the fluorescent quenching of EDAN with o-phthaldialdehyde (OPA). Quenching was most efficient at pH around 7 and by heating at 40 degrees C within the microplate reader. This optimized procedure has been applied to various carboxylic acids and other organic compounds, demonstrating that VFA exhibit the highest fluorescence responses with homogeneous results for the main ones (acetic, propionic and butyric acid, all mass concentration expressed as acetic acid equivalents). This protocol was calibrated against acetic acid and determination of VFA was thus possible in the range 3.9-2000 mg L-1 (acetic acid equivalents). Subsequent application to real samples (sewage sludges or anaerobically digested samples) and comparison to gas chromatography analyses gave accurate results, proving the great potential of our high-throughput microplate-based technique for the analysis of VFA. (C) 2011 Elsevier B.V. All rights reserved.

International audience; In the present work, a solid phase extraction (SPE) is hyphenated with an automatic MSFIA system to improve the selenite determination based on the reaction of selenite with aromatic o-diamines (such as 2,3-diaminonaphthalene (DAN)) to form the piazselenol complex. This reaction is greatly influenced by acid concentration, temperature, the time needed for colour development, and presence of foreign ions.For these reasons a thermostatic bath, glycine, and Na2-EDTA are used as heater, buffer, and masking agent, respectively. The principle of the determination is based on the sorption of the piazselenol onto a C18 membrane disk, followed by its elution by acetonitrile. The piazselenol can then be detected by absorptiometry or fluorometry, both detection techniques being tested in our system. The best detection limit (1.7 g L−1) and RSD (3.04%) are obtained by absorptiometry at 380 nm. Environmental samples were spiked and analyzed, with recoveries close to 100%.

International audience; Solid-phase extraction for cationic elements is a promising approach for water treatment or for analysis applications. However, supports that allow the selective extraction and/or preconcentration of metalloid species are still not widespread. A new chelating sorbent has been prepared by grafting 2,3-diaminonaphtalene (DAN) on Amberlite® XAD-4 resin beads via a diazo bridge. The synthesis was first carried out at a molecular level to optimise experimental conditions and to facilitate characterisation of solid sorbent by FTIR. TGA, Py-GC/MS experiments and back titration of amine functions showed that the sorbent was grafted. Se(IV) was retained by grafted Amberlite® XAD-4 with a rate of 88% at pH 2 and 80 °C. This paper presents a convenient way of grafting DAN on polystyrene-like resins and the first applications of these supports in solid-phase extraction of Se(IV).

Correspondance auteur: Boudenne J.L. E-mail: jean-luc.boudenne@univ-provence.fr; International audience; This paper presents a simple, rapid, and accurate method suitable for on-site measurement of short-chain volatile fatty acids (SCFA) in various environmental samples. This fluorimetric method involves a derivatization step of SCFA with N-(1-naphthyl)ethylenediamine (EDAN) and allows determination of acetic, butyric, propionic, valeric, lactic, succinic, and p-hydroxybenzoic acids in approximatively 10 min. To evaluate specificity and accuracy of the method, both laboratory-made waters and real samples ranging from wastewater plant and river to soils and composts have been tested. Good accuracy and correlation (r(2) = 0.9887) with HPIC determination have been obtained. The potential interference effect has been taken into account with compounds like humic substances, alcohols, amines, aldehydes, and metallic ions. Ibis method seems thus well designed for the determination of total SCFA in waters, in the range 0.84-500 mg/L. Because this method seems well suited for following of anaerobic treatment, it has been calibrated versus acetic acid-equivalent

Solid-phase extraction (SPE) of trace elements before their analysis has become a conventional pretreatment step of analytes because of their frequent low concentrations in numerous samples. Additionally, interfering compounds often accompagny analytes of interest, thus requiring a clean-up step. The preconcentration step and/or matrix removal can be efficiently improved by chemometric approaches allowing obtention of reliable results. Single variable approach is often used but is time and cost consuming, and may be the source of mistakes; multivariable approach allows to overcome these problems and increases the probability of global optimum finding. In order to obtain a set of experimental conditions for the selective extraction of Al(III) in water samples, onto a modified organic support (salicylic acid grafted on XAD-4), a multicriteria approach (response surface methodology) has been applied. The extraction method was optimized by the aid of a factorial design and a uniform shell Doehlert design for six variables: sample percolation flow rate, trace metal amount, sample volume, concentration and volume of HCl used for elution of aluminium. Results demonstrate the synergic effects of four factors and allow us to define working ranges for each parameter tested. The designed SPE procedure was then sucessfully applied to synthetic and real samples, issued from a potable water treatment unit.

In this work, Amberlite XAD-4 resin functionalized with salicylic acid was synthetized, characterized and applied as a new packing material for an on-line system to iron determination in aqueous samples. The detection method is based on the sorption of Fe(III) ions in a minicolumn containing the synthesized resin, followed by a desorption step using an acid solution and measurement of iron by vis-spectrophotometry (CAS method). The optimization of the solid-phase extraction system was performed using factorial design and Doehlert matrix considering six variables: sample percolation rate (0.5–9 ml min −1 ), sample metal concentration (20–200 μg l −1 ), flow-through sample volume (0–5 ml) (all three directly linked to the extraction step), elution flow-rate (0.5–9 ml min −1 ), concentration and volume of eluent (HCl 0.1–0.5 M) (all three directly linked to the elution step). The aim of this study was to obtain a set of operating ranges for the six variables tested in order to obtain – by means of a mathematical function allowing maximisation of each response (desirability function) – at least 90% of iron recovery rates. Using the experimental conditions defined in the optimization, the method allowed iron determination with achieved detection limit of 2.3 μg l −1 and precision (assessed as the relative standard deviation) of 9.3–2.8% for iron solutions of 10.0–150 μg l −1 . Real samples (coming from a water treatment unit) were used successfully when evaluating potentialities of the developed SPE procedure coupled to a spectrophotometric determination.

In this paper, a multivariable approach has been applied for the selective removing of Fe(III) and Al(III), in the range 0–200 μg l−1, in water samples onto a modified organic support (salicylic acid grafted on XAD-4). An empirical mathematical model was designed which establishes the relationship between the variation of the responses (extraction yields), and the variation of three factors (sample volume, sample percolation flow rate and amount of metallic ions present in the sample). To estimate the coefficients of the developed model, an uniform shell Doehlert design has been applied; these experiments consisted in GF-AAS determination of aluminium and iron amounts in eluates after percolation of samples through modified support. Results show a similar behaviour of the resin towards aluminium and iron with a preponderant effect of the percolation flow rate value; however this one is crucial for aluminium extraction and should be maintained below to 0.55 ml min−1 to reach a 95% Al3+ extraction yield (versus 2.25 ml min−1 for Fe3+). The optima determined by this experimental design approach have been further applied to the selective extraction of aluminium and iron from multielement synthetic samples and from real samples at the outlet of potable water treatment units.

International audience; Among commercially available sorbents, aromatic organic crosslinked copolymers allow to consider numerous ways of linking ligands. In this way, the grafting of salicylic acid and of its derivatives (methylene disalicylic acid and aurintricarboxylic acid) via the ketone, amide and diazo bridges on Amberlite® XAD‐4 resin and Empore™ SDB‐XC membrane have been carried out. The modified sorbents thus obtained have been appraised according to their grafing rate and their efficiency to selectively retain different metallic ions versus pH. The grafting of the sorbents permits to obtain pretty good yields. Extraction yield studies have revealed that the supports have the same behavior whatever the ligand grafted via a diazo or an amide bridge. Thus, increase of salicylic acid entity number does not improve the performance of the supports. However, bridge used during grafting seems to have an influence upon the extraction yields observed.

International audience; Fluorescence spectroscopy has potential for characterizing the water soluble fraction of soil organic matter. However, some questions remain unanswered: (i) can this technique be applied to a complex and evolving mixture of compounds and (ii) can the quality parameter obtained from fluorescence analysis be linked to climatic parameters and soil microbial activity. To answer these questions, a set of 98 soil water extracts, from a study of a 2.50-m-thick soil section in the vadose zone during a 7-month experiment was analyzed. Water-extracted organic matter (WEOM) content and the potential aerobic respiratory activity were measured in the laboratory, whereas environmental factors (rainfall soil temperature) were monitored on site. The humification index (HIX) was also calculated for the 98 samples. Results showed a significant positive correlation (R-2 = 0.87, P < 0.001) between the fluorescence signal and the WEOM content. A higher proportion of low molecular weight and size compounds was observed in the deepest layers than in the surface soils. The decrease in aerobic respiratory activity (from 0.9 to 0.4 mugO(2) g(-1)dw h(-1)) and in HIX (from 3.7 to 2.1) from the surface to the 1.5-m depth suggest that the small fluorescent compounds were more recalcitrant to biodegradation in the deep vadose zone. Heavy rainfall events (60 mm) resulted in a sharp decrease of HIX values (from 2.6 to 1.3) at the 1.5-m depth, probably the result of leaching of small compounds, whereas the WEOM content was stable (2 mg C L-1). Fluorescence spectroscopy was demonstrated to be useful for analyzing the fate of agricultural organic residues in soils

A fluorimetric procedure for the determination of aluminium with matrix removal in drinking water is proposed. The system is based both on the solid phase extraction of aluminium on a new chelating resin (XAD-4 modified by grafting salicylic acid) and the fluorimetric detection of a complex formed between 8-hydroxyquinoline-5-sulfonic acid (HQS) and Al(III), after elution of the resin by hydrochloric acid. The sorption and elution of aluminium were studied in both competitive and noncompetitive conditions, varying pH, flow-rates, volume and concentration of reagents, as well as time contact. The optimised procedure allows determination of Al3+ at the sub-ppb level (LOD: 0.2 microg L(-1) for 1 ml of sample) within a working range of 0.2-500 microg L(-1). The analytical procedure was successfully employed for the determination of aluminium in drinking water during and after flocculation/coagulation treatment processes.

International audience; Oxidation of phenol on platinum electrodes rapidly leads to the formation of a passivating film on the surface of these electrodes. Studies of cyclic voltammetry and chronoamperometry combined with high-performance liquid chromatography (HPLC) analyses have shown that the presence of carbon black avoids these phenomena of passivation and thus allows the complete mineralization of phenol. The nature of carbon black and the pH value are two important factors which are studied here. VULCAN XC-72 R, an intrinsic p-type semiconductor, having a large specific area, showed all its efficiency when cyclic voltammetry experiments were carried out in an acid medium (pH 2.2). HPLC analyses revealed the appearance of several by-products such as hydroquinone and benzoquinone, and maleic and fumaric acids.

The study of the fate and behaviour of organic and mineral pollutants in the biosphere needs a physico-chemical characterization of the receiving medium in order to assess transport and migration kinetics of these contaminants. Among constituents of receiving media, dissolved organicmatter (DOM) -term more often used for soils- and natural organic matter (NOM) -term more often used for waters- represent one of the essential components which regulate migration, transport and fate of these pollutants.These integrative terms cover a multitude of organic molecule families which present a large number and variety of functional groups that give them a very reactive character dependent on their intrinsic properties (solubility, hydrophobicity, size, complexation ability, pKa, toxicity).This research work aims to make a contribution to the characterization of DOM by focusing more specifically to the determination and analysis of carboxylic acid, thiol and amine functional groups.The methodology retained lies on the design of alternative analytical protocols based on a fluorimetric detection of targeted functional groups, following a step of a specific derivatization procedure.This report presents the criteria that have driven choice of reagents used for the derivatization and post-derivatization fluorimetric detection of functional groups, and the optimization of reactional conditions (pH, amount of reagents, ratios of reagents according to sample volumes, reactionkinetics) by use of screening procedures, experimental and desirability designs. It presents then the design of ready-to-use microplate assays for on-site analysis of carboxylic, thiol and amine compounds, and of a fully automated flow-system for the on-line analysis of VolatileFatty Acids (VFA).Finally, it presents the conclusive trials obtained with real samples coming from various environmental matrices (sewage sludges from wastewater treatment plants, natural and composted soils, bamboos …) along with the analytical features of the different analysis system developed., L’étude du devenir des contaminants organiques et minéraux dans la biosphère nécessite une caractérisation physico-chimique du milieu récepteur afin d’évaluer les cinétiques de transport et de migration de ces contaminants. Parmi les constituants des milieux récepteurs, la matière organiquedissoute (MOD) -terme plutôt réservée aux sols- et la matière organique naturelle (MON) -terme plutôt réservées aux eaux- représentent une des composantes essentielles qui va régir la migration, le transport et le devenir de ces contaminants.Ces termes intégrateurs recouvrent une multitude de familles de molécules organiques qui présentent un nombre important et une diversité de groupements fonctionnels qui leur procurent un caractère très réactif, dépendant de leurs propriétés intrinsèques (solubilité, hydrophobicité, taille,capacité complexante, pKa, toxicité).L’objectif de ce travail de recherche est d’apporter une contribution à la caractérisation de cette MOD en s’intéressant plus particulièrement à la détermination et au dosage des groupements fonctionnels acides carboxyliques, thiols et amines.La méthodologie retenue repose sur la mise au point de protocoles analytiques alternatifs basés sur une détection par fluorescence des groupements fonctionnels ciblés, après une étape préalable de dérivation spécifique.Ce mémoire présente les critères qui ont guidé les choix des réactifs utilisés pour la dérivation et la détection post-dérivation par fluorescence des groupements fonctionnels et l’optimisation des conditions réactionnelles (pH, concentrations des réactifs, ratios des réactifs en fonction desvolumes d’échantillons, cinétiques de réaction) par la mise en oeuvre de plans de criblage, de plans d’expériences et de désirabilité.Il présente ensuite la mise au point de kits d’analyse prêt-à-l’emploi pour l’analyse sur site des composés carboxyliques, thiols et amines, et d’un système en flux totalement automatisé pour l’analyse en continu pour le suivi des Acides Gras Volatils (AGV).Enfin, il présente les essais concluants obtenus avec des échantillons réels provenant de matrices environnementales très variées (boues de stations d’épuration, sols naturels et compostés, bambous,…) ainsi que les caractéristiques analytiques des différents systèmes mis au point.