[Show abstract][Hide abstract] ABSTRACT: Cet article a pour objectif de présenter les caractéristiques de l'extraction en phase solide pour les analyses environnementales à partir de matrices ou d'extraits liquides. Les principes fondamentaux qui régissent l'extraction sont expliqués afin de pouvoir choisir la nature et la quantité de phase extractante selon la matrice des échantillons et les propriétés des solutés recherchés en s'appuyant sur les mécanismes de rétention des phases. Les derniers développements concernant les formats disponibles, la nature des phases et l'automatisation sont présentés. Un intérêt particulier est porté aux phases sélectives émergentes, notamment celles qui agissent par reconnaissance moléculaire telles les immunoadsorbants ou les polymères à empreinte moléculaire permettant en une seule étape d'avoir un extrait propre. Les performances de leur couplage en ligne avec la séparation par chromatographie en phase liquide sont illustrées par des exemples dans le domaine environnemental. Quelques exemples particuliers à l'analyse des produits pétroliers sont également présentés.
Oil & Gas Science and Technology 11/2005; 60(6):899-912. DOI:10.2516/ogst:2005063 · 0.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An immunoaffinity solid-phase-extraction sorbent has been developed by raising polyclonal antibodies against propanil and covalently bonding them to activated silica. This immunosorbent (IS) had high affinity for propanil and for structurally related phenylurea herbicides whereas structurally related chloroanilines were retained only poorly. Studies of breakthrough volumes, capacity, and calibration ranges of selected pesticides showed that the antibodies have different affinities for each compound. Propanil and phenylureas could be quantitatively recovered by elution with methanol–water; average recoveries were close to 100%. The IS was also packed in a precolumn and coupled on-line to HPLC–UV. The high selectivity provided by the IS was demonstrated by comparing results with those obtained by use of a non-selective polymeric sorbent when both were used for direct extraction of propanil and phenylureas from a 50-mL sample of river-Seine water spiked at 0.1 g L–1 or from lemon juice spiked at 50 g L–1.
[Show abstract][Hide abstract] ABSTRACT: There is a need for a better characterization of sludges from wastewater treatment plants which are destined to be spread on agricultural lands. Inorganic pollutants are regularly controlled but organic pollutants have received few attention up to now. On this paper, we have been interested on the analysis of the 16 polycyclic aromatic hydrocarbons (PAHs) listed in the US Environmental Protection Agency (US EPA) priority list and more particularly of the six PAHs listed in the European community list (fluoranthene, benzo[b and k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene). The analysis step consists on liquid chromatography with both fluorescence and UV detections as described in the EPA Method 8310. As for the extraction step, several techniques such as supercritical fluid extraction, pressurized liquid extraction, focused microwave extraction in open vessels, Soxhlet and ultrasonic extractions are compared after optimization of the experimental conditions (solvent nature and quantity, temperature, pressure, duration, ... ) and validation with certified sludges. When optimized, these five extraction techniques are as much efficient with similar relative standard deviation. Whatever the extraction techniques used, the whole analysis protocol permits to quantify PAHs in the range of 0.09 to 0.9 mg/kg of dried sludges.
Journal of Chromatography A 06/2003; 995(1-2):87-97. DOI:10.1016/S0021-9673(03)00497-7 · 4.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Direct, selective solid-phase extraction of triazines from aqueous samples is presented using a molecularly imprinted polymer (MIP) made with terbutylazine as template molecule. After optimization of the steps of the procedure, 14 triazines including degradation products were studied and satisfactory extraction recoveries were obtained except for thiotriazines. By comparing results obtained with the terbutylazine MIP and a similar non-imprinted polymer, it was determined that retention was achieved via specific interactions except for hydroxyterbutylazine. Selectivity of the extraction procedure was also verified by applying the MIP for the extraction of phenylureas that were not retained on it. The effects of the charge distribution and of molecular volume of the triazines (obtained by molecular modeling) on the selectivity of interactions between the analytes and the MIP were studied. However, when the optimized procedure was applied to real samples, low extraction recoveries were obtained due to strong matrix effects: ion-exchange occurs between the carboxylate groups of the MIP and the ionic species of the sample, that prevents subsequent specific interactions. By introducing an acid wash step, the procedure was successfully applied for the class-selective extraction of triazines from industrial effluent and surface water samples. Finally, increased extraction recoveries were achieved for the polar degradation products of triazines by using a mixed-phase composed of a polymeric sorbent and the MIP.
Journal of Chromatography A 06/2003; 999(1-2):23-33. DOI:10.1016/S0021-9673(03)00552-1 · 4.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Phenolic compounds present in olive mill wastewater (OMW) need to be quantified because of their pollution capacity toward the environment. In the present study, six representative phenolic compounds of OMW were chosen to develop a LC-MS method. The high polarity of the compounds caused problems when using traditional reversed-phase liquid chromatography (RPLC). Consequently, a method was developed on another kind of chromatographic phase: Porous Graphitic Carbon (PGC) involving the use of a tetrahydrofuran (THF) gradient. The influence of THF as mobile phase in LC-MS coupling, which is not common practice, was evaluated. In Atmosperic Pressure Chemical Ionisation (APCI) in the negative ion mode, the presence of THF in the mobile phase did not degrade the MS signal of the target compounds in the conditions studied. On the contrary, an improvement was even observed when the percentage of THF increased. The proposed PGC-LC-MS method was selective and linear for the six phenolic compounds analysed with limits of quantification lower than 5 ppm in all cases. The precision was satisfactory (pooled RSD around 6%). The analyses of OMW matrix spiked sample confirmed the good performance of the proposed method.
Journal of Chromatography A 01/2002; 937(1-2):21-9. DOI:10.1016/S0021-9673(01)01309-7 · 4.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: PAHs and their nitrated derivatives (Nitro-PAHs) have been analyzed in extracts from particulate matter by GC-MS and GC-MS-MS. Using GC-MS, most of these compounds could not be detected in raw extracts or their confirmation was uncertain because of interfering compounds from the matrix. Detection and quantification was greatly improved by using GC-MS-MS. Limits of detection were lower than 40 pg (injected) in standard solution and in diesel particulate matter extracts (for 10 mg of particles extracted). Low traces of PAHs and Nitro-PAHs, in the range of a few pg·m–3, could be detected without purification or fractionation of the extract.
[Show abstract][Hide abstract] ABSTRACT: "Earthy-musty" off-flavor problems in water samples are due to organic compounds present at the sub-part-per-trillion level. Numerous analytical methods such as purge and trap, liquid/liquid extraction, and closed-loop stripping analysis (CLSA) followed by GC/MS analysis have been used to determine these compounds. However, these methods offer poor sensitivity (detection limits of approximately 1 to 10 ng/L) when compared to the 20-30 pg/L of sensorial sensitivity. The purpose of this study was to develop a new method involving a modified CLSA preconcentration technique together with large volume injection GC/MS in order to attain analytical sensitivity equal to or better than olfactory sensitivity. For eight target compounds that cause taste and odor problems in water at trace levels, the method developed was linear in the 0.05-10 ng/L range and provided recoveries greater than 70% together with satisfactory repeatability. Detection limits as low as 15-30 pg/L were achieved, representing a 50-fold improvement in sensitivity as compared to current methods. The accuracy and sensitivity of the method were demonstrated in different aqueous matrixes, including raw surface water. The method was successfully applied to earthy-musty water samples that had remained unsolved by conventional techniques, thus proving its effectiveness.
[Show abstract][Hide abstract] ABSTRACT: A description of immunosorbents, which are solid-phase extraction sorbents based on molecular recognition using antibodies, is provided. The sysntesis of immunosorbents for small molecules is discussed as are the main parameters governing their extraction. The high selectivity of these reagents is demonstrated in a number of applications.
[Show abstract][Hide abstract] ABSTRACT: Adsorbents involving antigen-antibody interactions, so-called immunosorbents, have high affinity and class-selective extraction
properties. Although most studies of immunosorbents are based on the use of polyclonal antibodies, to ensure a good repeatability
with this kind of sorbent monoclonal antibodies are required. This study shows that the cross-reactivity of monoclonal anti-isoproturon
antibodies is similar to that of polyclonal anti-isoproturon antibodies. To reduce the price of the resulting immunosorbent,
the bonding density has been optimized. The choice of activated silica rather than Sepharose as solid support is discussed.
The effect of sample volume and of the amount of immunosorbent on extraction recoveries for some phenylureas has been studied.
It appears that the amount of immunosorbent can be readily adapted to the detection limit required.
[Show abstract][Hide abstract] ABSTRACT: O-PAHs have been analyzed in extracts of particulate matter by GC-MS-MS and GC-MS. Using GC-MS, most O-PAHs could not be detected
in raw extracts, or their confirmation was uncertain due to interfering compounds from the matrix. Detection and quantification
was greatly improved by using GC-MS-MS. Linearity was observed in the range from 10 to 1000 pg injected. Low traces of O-PAHs,
in the range of a few pg·m−3 of air, could be detected without purification or fractionation of the extract.
[Show abstract][Hide abstract] ABSTRACT: A selective clean-up procedure using immunoaffinity solid-phase extraction was applied for the trace-level determination of polycyclic aromatic hydrocarbons (PAHs) in urban waste water and sewage sludges used for soil amendment. Anti-pyrene antibodies have been immobilized on a silica-based sorbent and the cross-reactivity of the antibodies towards structurally related compounds were allowed to extract the whole class of priority PAHs. The selectivity of the antibodies provided clean extracts from sludges and, therefore, the identification and quantification were shown to be easier using either liquid chromatography (LC) with UV diode array and fluorescence detection in series or gas chromatography-mass spectrometry (GC-MS), although some loss of up to 50% was observed for the clean-up. The identification of the PAHs by matching of UV and MS spectra was greatly improved. The procedure, including immunoclean-up and LC coupled to diode array and fluorescence detection, was validated using certified reference materials with native PAHs of concentrations in the range of 0.57-2.16 mg/kg (dry sludges).
Journal of Chromatography A 11/1999; 859(1):29-39. DOI:10.1016/S0021-9673(99)00824-9 · 4.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this review is to provide updated information about the most important features of the new solid-phase extraction (SPE) materials, their interaction mode and their potential for modern SPE. First, the recent developments are given in formats, phases, automation, high throughput purpose and set-up of new types of procedures. Emphasis is then placed on the large choice of sorbents for trapping analytes over a wide range of polarities, such as highly cross-linked copolymers, functionalized copolymers, graphitized carbons or some specific n-alkylsilicas. The method development is given which is based on prediction from liquid chromatographic retention data or solvation parameters in order to determine the main parameters of any sequence (type and amount of sorbent, sample volume which can be applied without loss of recovery, composition and volume of the clean-up solution, composition and volume of the desorption solution). Obtaining extracts free from matrix interferences in a few steps--one step when possible--is now included in the development of SPE procedure. New selective phases such as mixed-mode and restricted access matrix sorbents or emerging phases such as immunosorbents or molecularly imprinted polymers are reviewed. Selectivity obtained by combining two sorbents is described with the use of ion-exchange or ion-pair sorbents. Special attention is given to complete automation of the SPE sequence with its on-line coupling with liquid chromatography followed by various detection modes. This represents a fast, modern and reliable approach to trace analysis. Many examples illustrate the various features of modern SPE which are discussed in this review. They have been selected in both biological and environmental areas.
Journal of Chromatography A 10/1999; 856(1-2):3-54. DOI:10.1016/S0021-9673(99)00832-8 · 4.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A phosphatase inhibition assay using commercially available components has been developed for the detection of cyanobacterial toxins in drinking and surface water samples. The assay is simple, economic and rapid. Results are obtained in 1h on a 96-well microtitre plate. The test uses a type 2A protein phosphatase whose activity is inhibited proportionally to the toxin concentration and is measured by means of a colourimetric reaction. Two procedures of the tests have been optimised using the same phosphatase, but different working conditions. The first one allows a direct estimation of the concentration of microcystin-LR in the range 0.4–10μg/l and is used to calculate the sample dilution required for the second procedure, which has been optimised in order to be much more accurate with a working range between 0.2 and 0.8μg/l (concentration in the sample, which corresponds to 0.1–0.4μg/l in the well). An enrichment using solid phase extraction on octadecyl silica has been described for samples containing less than 0.2μg/l of microcystin. A repeatability of 8% at the IC50 level has been obtained and the IC50 value is 0.21±0.02μg/l (concentration in the well). Inhibition of enzyme activity by other toxins such as microcystin-YR and microcystin-RR has also been evaluated. Particular attention has been paid to the effect of the sample matrix on the assay. Several drinking and surface waters have thus been investigated. Validation of the assay has been performed by comparing the phosphatase inhibition assay results to the liquid chromatography results for the same samples. A good correlation (R2=0.96) has been observed for samples containing microcystin-LR.
[Show abstract][Hide abstract] ABSTRACT: A new extraction immunosorbent involving antigen-antibody interactions was coupled on-line to liquid chromatography for the selective extraction in aqueous samples of benzidine and congeners, widely used as intermediate compounds in the manufacturing of dyes and pigments. Due to the cross-reactivity of the antibodies for analytes with chemical structures closely related to that of the analyte used for immunization, the immunoextraction sorbent was shown to be able to extract aminoazobenzene and related azo dyes with good recoveries. The on-line coupling was optimized for the trace determination of benzidine, dichlorobenzidine, aminoazobenzene and some azo dyes with detection limits in the range 0.1 to 1 microgram/l. The high selectivity of the immunoextraction was shown by comparing the analysis of an industrial textile effluent obtained using precolumns packed either with a non-selective polymeric sorbent or with the anti-benzidine immunosorbent. In such complex samples, extraction and clean-up are achieved in the same step.
Journal of Chromatography A 07/1999; 846(1-2):317-29. DOI:10.1016/S0021-9673(99)00155-7 · 4.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The selective isolation of PAHs from complex environmental mixtures was accomplished by means of a new methodology based on antigen--antibody interactions. This method consists on the extraction of PAHs from water samples onto an anti-fluorene immunosorbent (IS) followed by liquid chromatography with diode array detection. Environmental sediments and a sludge reference material containing PAHs were analyzed using this methodology in order to validate the performance of the IS for the cleanup procedure of such materials. Sediments were extracted by sonication with dichloromethane/methanol (2:1), and the extracts were brought to a volume of 100 mL of water in order to perform the extraction with the anti-fluorene IS. The reliability of the cleanup achieved by the IS was well demonstrated in the analysis of sediment and sludge complex samples containing the priority PAHs established by the U.S. EPA at concentrations varying from 56 micrograms/kg to 26 mg/kg. Results were compared to those obtained with conventional cleanup procedures showing a better selectivity for PAHs. The chromatograms presented a clear baseline allowing the determination and quantification of PAHs at the ppb level. Using immunosorbents, extraction, trace enrichment, and cleanup were accomplished in only one step.
[Show abstract][Hide abstract] ABSTRACT: The non-uniform affinity of polyclonal antibodies is a major problem when these antibodies are used in immunochemical-based environmental applications. A specific affinity chromatography procedure was developed to extract selectively anti-isoproturon antibodies from a crude polyclonal antiserum. These antibodies were fully characterized and helped to improve the performances of immunoaffinity extraction and an indirect enzyme immunoassay.