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A new method involving matrix solid-phase dispersion (MSPD) and dispersive liquid-liquid microextraction (DLLME) was optimized with the aid of stoichiometry and applied to the extraction, purification, and determination of benzimidazole residues in vegetables. Carbendazim, thiabendazole, and thiophanate-methyl were selectively extracted from vegetables using cucurbit[7]uril as the MSPD extractant and transferred to an aqueous solution, then further enriched using DLLME with acetonitrile and chloroform as dispersive and extraction solvents, respectively. The optimal extraction conditions of MSPD and DLLME were selected by two-level full-factorial design and central-composite design (CCD). The developed method (MSPD-DLLME-HPLC-UV) showed good linearity in the range of 0.025-5 μg/g, with R 2 > 0.9984. Intra- and interday precisions were 5.3-10.9% and 10.6-12.4%, respectively, and the limit of detection was between 0.004 and 0.007 μg/g of fresh weight. This method was applied to the analysis of four different types of vegetables, and the recoveries ranged from 65.4% to 124.0%. The method was environmentally friendly, easy to operate, and sensitive., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Benzimidazoles, commonly used as pesticides and veterinary drugs, have posed a threat to human health and the environment due to unreasonable use and lack of valid regulation. Therefore, an up-to-date and comprehensive summary of the pretreatment and analytical approaches in different substrates is urgently needed. The present review consequently updates and covers various newly developed pretreatment methods (e.g., cationic micellar precipitation, magnetic-solid phase extraction, hollow fiber liquid phase microextraction, disperse liquid-liquid microextraction-solidified floating organic drop, stir cake sorptive extraction, solid phase microextraction method, QuEChERS, and molecular imprinted polymer-based methods) since 2005. The review also elaborates and discusses different determination methods (e.g., newly developed HPLC and related methods, improved spectrofluorimetry methods, capillary electrophoresis, and the electrochemical sensor). Furthermore, some critical points and prospects are highlighted, to describe the trends in this area., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The functionalization of covalent organic frameworks (COFs) enhances chemical properties and expands future applications. Herein, a facile strategy for sulfoacid-functionalized COF is presented through post-modification of covalent triazine frameworks (CTFs) platform. The magnetic solid phase extraction (MSPE) material is obtained by anchoring in situ Ni particles on CTF support (Ni/CTF-SO 3 H) possessing a dual retention mechanism combining hydrophilic-lipophilic-balance (HLB) and cation-exchange interaction. We established the (Ni/CTF-SO 3 H)-MSPE method for selectively enriching carbendazim (CBZ) and thiabendazole (TBZ) from food samples and reducing matrix effect simultaneously. The method detection limit is 1.23-7.05 µg kg -1 for CBZ and TBZ in vegetable, fruit and juice samples, determined by high-performance liquid chromatography-ultraviolet detector. The recoveries of spiked CBZ and TBZ in the samples are 80.2-115.1% and RSDs 6.0-11.4%, depending on both analytes and samples. Our work provides a unique perspective in the development of functionalized COFs as a versatile HLB/cation-exchange mixed-mode SPE sorbent for extraction of basic analytes in complex matrix., Competing Interests: Declaration of Competing Interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted, (Copyright © 2020 Elsevier B.V. All rights reserved.)

Ultra-high performance liquid chromatography (UHPLC) coupled with fluorescence detection (FL) has been proposed for the first time to determine thirteen benzimidazoles (BZs) in farmed fish samples. In order to optimize the chromatographic separation, parameters such as mobile phase composition and flow rate were carefully studied, establishing a gradient mode with a mobile phase consisted of water (solvent A) and acetonitrile (solvent B) at a flow rate of 0.4 mL/min. The separation was performed on a Zorbax Eclipse Plus RRHD C 18 column (50 × 2.1 mm, 1.8 μm), involving a total analysis time lower than 12 min. Salting-out assisted liquid-liquid extraction (SALLE) was applied as sample treatment to different types of farmed fish (trout, sea bream and sea bass). To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized including the amount of sample, type and volume of the extraction solvent, and the nature and amount of the salt used. Characterization of the method in terms of performance characteristics was carried out, obtaining satisfactory results for the linearity (R 2  ≥ 0.997), repeatability (RSD ≤ 6.1%), reproducibility (RSD ≤ 10.8%) and recoveries (R ≥ 79%; RSD ≤ 7.8%). Detection limits between 0.04-29.9 μg kg -1 were obtained, demonstrating the applicability of this fast, simple and environmentally friendly method., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A novel method based on capillary zone electrophoresis-tandem mass spectrometry has been proposed and validated for the identification and simultaneous quantification of twelve benzimidazoles in meat samples. Electrophoretic separation was carried out using 500mM formic acid (pH 2.2) as background electrolyte and applying a voltage of 25kV at 25°C. In order to improve the sensitivity, stacking mode injection was applied, using as injection solvent a mixture of 30:70 acetonitrile/water at 50mbar for 75s. Sensitivity enhancement factors from 74 to 317 were obtained under these conditions. Detection using an ion trap as analyzer, operating in multiple reactions monitoring mode was employed. The main MS/MS parameters as well as the composition of the sheath liquid and other electrospray variables were optimized in order to obtain the highest sensitivity and precision in conjunction with an unequivocal identification. The method was applied to poultry and pork muscle samples. The deproteinization of samples and extraction of benzimidazoles was carried out with acetonitrile. MgSO 4 and NaCl were added as salting-out agents. Subsequently, dispersive liquid-liquid microextraction was applied as clean up procedure. The organic layer (acetonitrile, used as dispersant) containing the benzimidazoles was mixed with the extractant (chloroform) and both were injected in water, producing a cloudy solution. Recoveries for fortified samples were higher than 70%, with relative standard deviations lower than 16% were obtained in all cases. The limits of detection were below 3μgkg -1 , demonstrating the applicability of this fast, simple, and environmentally friendly method., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this work the atmospheric pressure ionization behavior and the tandem mass spectrometry fragmentation of 19 benzimidazoles was studied. Several atmospheric pressure ionization (API) sources (ESI, APCI and APPI) were evaluated showing that APCI was the best option, mainly for KETO-TCB that provided a 20 times improvement versus ESI. From the studies of tandem mass spectrometry, fragmentation pathways were proposed thus characterizing the most abundant and interesting product ions and selecting the most abundant and selective ones for the confirmatory quantitative method performed in SRM mode in a triple quadrupole mass analyzer. For quantitative analysis, the 19 benzimidazoles were separated in less than 7 min using a C18 column packed with superficially porous particles providing high efficiency within the range of UHPLC. A QuEChERS-like sample treatment was applied to milk samples before the UHPLC-APCI-MS/MS determination providing method limits of quantitation that ranged from 0.6 to 3 μg kg(-1) and showing good repeatability (RSD: 2-18%) and accuracy (relative errors: 1-23%) suitable for using this method for routine analysis., (Copyright © 2013 Elsevier B.V. All rights reserved.)

This paper presents a sensitive and confirmatory multi-residue method for the analysis of 23 veterinary drugs and metabolites belonging to three classes (nitroimidazoles, benzimidazoles, and chloramphenicols) in porcine muscle, liver, and kidney. After extracted with ethyl acetate and basic ethyl acetate sequentially, the crude extracts were defatted with hexane and further purified using Oasis MCX solid-phase extraction cartridges. Rapid determination was carried out by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Data acquisition was performed under positive and negative mode simultaneously. Recoveries based on matrix-matched calibrations for meat, liver, and kidney ranged from 50.6 to 108.1%. The method quantification limits were in the range of 3-100ng/kg., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Benzimidazoles (BZDs) are anthelmintic agents widely used in veterinary medicine. Their use in food-producing animals increases the possibility of residues appearing in animal tissues and products. Most analytical procedures reported for the determination of BZDs have been developed based on liquid chromatography (LC) because of their polar nature - zwitterionic - and thermal lability. To our knowledge, the determination of these compounds by capillary electrophoresis coupled to mass spectrometry (CE-MS) has not yet been described. In this work CE-MS is proposed for the identification and simultaneous quantification of several benzimidazoles in egg samples. The target compounds were 2-aminobenzimidazole, carbendazim, albendazole-2-aminosulphone, 5-hydroxy-thiabendazole, oxibendazole, albendazole, fenbendazole, oxfendazole, albendazole-sulphone, fenbendazole-sulphone. Optimization of the composition and nature - organic/aqueous - of both the electrophoretic separation buffer and the injection medium was carried out with a view to obtaining the best sensitivity and separation efficiency for the CE-MS coupling. A comparative study was carried out on different sample treatments for analyte extraction from egg samples. Two of them comprised a solvent extraction step followed by clean-up using a new commercial polymeric sorbent (Evolute ABN(©)), and the third was a particularization of the general extractive method so called Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS). Different modifications of the QuEChERS method were assayed, which included a later preconcentration step based on either SPE with MCX(©) sorbents or evaporation. The whole optimized method (QuEChERS with preconcentration prior to CE-MS) was validated according to the 2002/657/EC decision obtaining a CE-MS method sufficiently reliable and robust to determine residues of these compounds in egg samples of different origins with limits of detection between 3 and 51 μgL(-1) (S/N=3) and recoveries in the 74-112% range., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Triclabendazole is the only anthelmintic drug, which is active against immature, mature and adult stages of fluke. The objective of this work was to develop an analytical method to quantify and confirm the presence of triclabendazole residues around the MRL. In this work, a new analytical method was developed, which extended dynamic range to 1-100 and 5-1000 μg kg(-1) for milk and tissue, respectively. This was achieved using a mobile phase containing trifluoroacetic acid (pK(a) of 0.3), which resulted in the formation of the protonated pseudomolecular ions, [M+H](+), of triclabendazole metabolites. Insufficient ionisation of common mobile phase additives due to low pK(a) values (<2) was identified as the cause of poor linearity. The new mobile phase conditions allowed the analysis of triclabendazole residues in liver, muscle and milk encompassing their EU maximum residue levels (MRL) (250, 225 and 10 μg kg(-1) respectively). Triclabendazole residues were extracted using a modified QuEChERS method and analysed by positive electrospray ionisation mass spectrometry with all analytes eluted by 2.23 min. The method was validated at the MRL according to Commission Decision (CD) 2002/657/EC criteria. The decision limit (CCα) of the method was in the range of 250.8-287.2, 2554.9-290.8 and 10.9-12.1 μg kg(-1) for liver, muscle and milk, respectively. The performance of the method was successfully verified for triclabendazole in muscle by participating in a proficiency study, the method was also applied to incurred liver, muscle and milk samples., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In this work, an ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) procedure was developed for the extraction of a group of pesticides (carbendazim/benomyl, thiabendazole, fuberidazole, carbaryl and triazophos) and some of their key metabolites in soils (2-aminobenzimidazole, metabolite of carbendazim and 1-naphthol, metabolite of carbaryl) from aqueous soil extracts, using high performance liquid chromatography (HPLC) with fluorescence detection (FD). Analytes were previously extracted from four soils with different physicochemical properties (forestal, ornamental, garden and lapilli soils) by ultrasound-assisted extraction (USE). The IL 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIm][PF(6)]) and methanol (MeOH) were used as extraction and dispersion solvent, respectively, for the DLLME procedure. Factors affecting IL-DLLME (sample pH, IL amount, volume of dispersion solvent and sodium chloride percentage) were optimized by means of an experimental design, obtaining the most favorable results when using 117.5 mg of IL and 418 μL of MeOH to extract the compounds from the aqueous soil extracts at pH 5.20 containing 30% (w/v) NaCl. Calibration of the USE-IL-DLLME-HPLC-FD method was carried out for every type of soil and accuracy and precision studies were developed at two levels of concentration, finding that no significant differences existed between real and spiked concentrations (Student's t test). LODs achieved were in the low ng/g range., (Copyright © 2010 Elsevier B.V. All rights reserved.)

A fast and flexible multi-residue procedure for effective extraction of benzimidazole fungicides and the related transformation products in various raw agricultural commodities is developed for direct and simultaneous analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The new sample preparation method, introduced to allow direct extraction of the labile fungicides as the intact forms in complex matrices, is achieved using a conservative homogenizing extraction and multifunction adsorption cleanup (CHEMAC), which basically involves salting-out partitioning/extraction with acetate-buffered acetonitrile at low-temperature and sequential rapid solid-phase dispersive cleanup with a ternary sorbent mixture. The CHEMAC procedure was optimized and further modified by incorporating several pretreatment variables influencing sample stability and process efficiency, such as pH, temperature, salt and sorbent utilized. By using CHEMAC, a noteworthy improvement in extraction recoveries was obtained for the problematic fungicides, while no significant differential matrix effects were detected on the LC-MS/MS analysis in all 9 matrices. The in-source fragmentation of benomyl occurred but caused no cross-talk interference in multi-component analysis. Thus the CHEMAC-based LC-MS/MS strategy can serve as an attractive approach to satisfactory overall process efficiencies (70-92%) with acceptable repeatability (relative standard deviations below 16%) for all the analyte-matrix combinations. Mean accuracies were obtained within the range of 70-110% at fortified levels of 1-500 ng/g, with intra-day and inter-day variations less than 15 and 20%, respectively. The successful practical application of the proposed method to real samples has also been demonstrated., (2010 Elsevier B.V. All rights reserved.)

A new UHPLC-MS/MS (ultra high performance liquid chromatography coupled to tandem mass spectrometry) method was developed and validated to detect 38 anthelmintic drug residues, consisting of benzimidazoles, avermectins and flukicides. A modified QuEChERS-type extraction method was developed with an added concentration step to detect most of the analytes at <1 microg kg(-1) levels in milk. Anthelmintic residues were extracted into acetonitrile using magnesium sulphate and sodium chloride to induce liquid-liquid partitioning followed by dispersive solid phase extraction for cleanup. The extract was concentrated into dimethyl sulphoxide, which was used as a keeper to ensure analytes remain in solution. Using rapid polarity switching in electrospray ionisation, a single injection was capable of detecting both positively and negatively charged ions in a 13 min run time. The method was validated at two levels: the unapproved use level and at the maximum residue level (MRL) according to Commission Decision (CD) 2002/657/EC criteria. The decision limit (CCalpha) of the method was in the range of 0.14-1.9 and 11-123 microg kg(-1) for drugs validated at unapproved and MRL levels, respectively. The performance of the method was successfully verified for benzimidazoles and levamisole by participating in a proficiency study.

A new analytical method that uses high performance liquid chromatography-diode array detector (HPLC-DAD) was developed for the analysis of 14 benzimidazoles residues, including metabolites, in bovine liver. Samples were extracted using two different extraction procedures: with phosphate buffer after enzymatic hydrolysis (method A) or using organic solvent, i.e. acetonitrile (method B). Then, samples were purified on a strong cation exchange (SCX) cartridge and analyzed in HPLC/DAD. The recovery percentages, obtained spiking the matrix (liver) at concentrations of 500 and 100 microg kg(-1) with a standard mixture of benzimidazoles, were in the range 6-101% and 80-102% for methods A and B, respectively. The repeatability of the methods was assessed in all cases by the % of correlation value (CV) that was lower than 19%. The limits of quantification (LOQs) in the matrix for methods A and B were in the range 40-60 and 20-50 microg kg(-1), respectively. The best of the two methods, method B, was used for the analysis of 10 bovine liver samples., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)

The screening method for the determination of residues of 19 benzimidazoles (parent drugs and their metabolites) and levamisole in bovine milk has been developed and validated. Milk samples were extracted with ethyl acetate, sample extracts were cleaned up by liquid-liquid partitioning with hexane and acidic ethanol. Liquid chromatography-single-quadrupole mass spectrometry was used for the separation and determination of analytes. The method was validated in bovine milk, according to the CD 2002/657/EC criteria. An alternative approach to the validation of the method was applied ("sum MRL" substances). The method was successfully verified in CRL proficiency test.

This work reports a new sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, confirmation and quantification of forty-six pesticides and transformation products belonging to different chemical classes in wines. The proposed method makes use of a solid-phase extraction (SPE) procedure with Oasis HLB cartridges that combines isolation of the pesticides and sample clean-up in a single step. Analysis is performed by liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-MS/MS) operated in the selected reaction monitoring (SRM) mode, acquiring two specific precursor-product ion transitions per target compound. An investigation of matrix effects has been performed during method validation showing medium to low effects for the majority of the compounds. Limits of detection (LODs) were in the range 0.0003-0.003 mg L(-1) and limits of quantification (LOQs) were in the range 0.001-0.01 mg L(-1). The average recoveries, measured at two concentration levels (0.010 and 0.050 mg L(-1)), were in the range 70-110% for most of the compounds tested with % relative standard deviations below 20%, while a value of 0.010 mg L(-1) has been established as the method limit of quantification (MLOQ) for all target species. Expanded uncertainty values were in the range 10-40% while the Horrat ratios were below 1. The method has been successfully applied to the analysis of 60 wine samples in the course of an annual monitoring study with carbendazim-benomyl, thiophanate-methyl and carbaryl being the most frequently determined pesticides.

A method based on ultra-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry (UPLC-MS/MS) for the determination of six thyreostatic drugs in thyroid tissue has been optimised and validated in accordance with Decision 2002/657/EC. Sample extraction was evaluated in methanol and in ethyl acetate, the latter which gave better results. Two clean-up strategies were compared: one based on silica cartridges (SPE), and the other, on gel permeation chromatography (GPC). Recoveries ranged from 40% to 79% for the SPE approach and from 80% to 109% for GPC. Quantification was performed with blank tissue samples spiked with the analytes in the range 50-500microgkg(-1). 5,6-Dimethyl-2-thiouracil and 2-mercaptobenzimidazole-d(4) were used as internal standards. Decision limit (CCalpha) and detection capability (CCbeta) ranged from 1 to 15microgkg(-1) and from 6 to 25microgkg(-1), respectively. The accuracy of the method was calculated as percent error, which was less than 10%. The relative standard deviation in reproducibility conditions ranged between 2% and 14%.

Microwave-assisted extraction (MAE) was carried out for the determination of the fungicides thiophanate methyl [1.2-alpha-(3-methoxycarbonyl-2-thioureido)benzene] and carbendazim (methyl benzimidazol-2-ylcarbamate) in vegetable samples. Two vegetable samples, cabbage and tomatoes, were fortified with the two pesticides and subjected to MAE followed by cleanup to remove co-extractives prior to analysis by high-performance liquid chromatography (HPLC). Using the selected microwave exposure time and power setting, the recoveries of carbendazim ranged from 69 to 75%. But thiophanate methyl could not be recovered as the parent compound. It was converted and recovered as carbendazim. The conversion was quantitative as confirmed by high-performance liquid chromatography-mass spectrometry (HPLC-MS).

The enantiomeric separation of cetirizine and oxfendazole on a Chiralpak AD column using subcritical fluid chromatography has been studied in this work. The enantioseparation of cetirizine was only possible when 2-propanol was used as a modifier, obtaining better results in presence of the additives triethylamine (TEA) and trifluoroacetic acid (TFAA). On the contrary, 2-propanol provided the lowest enantioresolutions for oxfendazole, in this case the best results in terms of high resolution and short analysis time were obtained with ethanol. The study of the temperature effect revealed that in the case of cetirizine using 2-propanol, and oxfendazole using methanol, the separation was enthalpy-driven and the isoelution temperature was above the working range. Using ethanol or 2-propanol, the results showed that the oxfendazole enantioseparation was entropically driven and the isoelution temperatures were below the range studied.

A multi-residue method using pressurized liquid extraction (PLE) and liquid chromatography-quadrupole ion trap-triple stage mass spectrometry (LC-IT-MS(3)) has been developed for determining trace levels of pesticides in fruits. The selected pesticides can be distinguished in: benzimidazoles and azoles, organophosphorus, carbamates, neonicotinoids, and acaricides. PLE has been optimized to extract these pesticide residues from oranges and peaches by studying the effect of experimental variables on PLE efficiency. Samples were extracted at high temperature and pressure (75 degrees C and 1500psi) using ethyl acetate as extraction solvent and acidic alumina as drying agent. The recoveries obtained by PLE ranged from 58% to 97% and the relative standard deviation (RSDs) from 5% to 19%. The limits of quantification (LOQs) of the compounds were from 0.025 to 0.25mgkg(-1), which are well-below the maximum residue limits (MRLs) established by the European Union (EU) and the Spanish legislations.

This study used capillary electrophoresis (CE) to investigate the simultaneous separation and on-line concentration of five pesticides: amitrole (AMT), carbendazim (MBC), 2-aminobenzimidazole (ABI), thiabendazole (TBZ) and 1,2-diaminobenzene (DAB). A volatile migration buffer was used for the investigation because of the applicability to mass spectrometric (MS) detection. They were separated completely at pH 4.0 as a result of changing pH using formic acid-ammonium formate buffer. Values of the dissociation constant for MBC and DAB estimated from the changes in the mobility with pH showed good agreement with values in the literature. Dissociation constants for AMT and TBZ were estimated. Limits of detection (LODs) for the analytes were on the ppm level with UV detection under the optimized separation condition. On-line concentration by simple stacking mode was not effective except to 2-aminobenzimidazole because of the peak tailing. The addition of formic acid to sample matrix improved the peak shapes. That improvement may be attributed to transient isotachophoretic effect. The concentration factors obtained from the comparison of the LODs were in the range of 7.6-27-fold. This concentration method was applied preliminarily to CE with MS detection.

This paper describes a method for extraction of tapazol, thiouracil, methylthiouracil, propylthiouracil and mercaptobenzimidazol (MBI) from thyroid tissue. The solid-phase extraction procedure is optimized to obtain the maximum results for the main thyreostats including MBI. Different combinations of sample application, column conditioning and wash steps were tested. The analytes were extracted from the matrix with methanol. After solid-phase extraction they were derivatised with 7-chloro-4-nitrobenzo-2-furazan. Determination is carried out using liquid chromatography-electrospray mass spectrometry. The identification of the analytes was performed according to the final revision of the EU criteria (93/256/EC decision). The detection capability was 20 microg kg(-1) for all mentioned thyreostats.

A simple method has been developed for the simultaneous determination of triclabendazole and its metabolites (sulphoxide and sulphone) in bovine milk by reversed-phase high-performance liquid chromatography (HPLC). A milk sample was homogenized with sodium sulfate anhydrous and acetonitrile, and centrifuged. The supernatant was isolated, rinsed with n-hexane saturated with acetonitrile, and evaporated. The residue was dissolved with 0.1 M potassium dihydrogenphosphate, and 0.1 M sodium hydrogencarbonate, and then cleaned up on a Bond Elut C18 cartridge. The three compounds were separated on a Capcell Pak C18 UG 120 (5 microm, 150x4.6 mm I.D.) column and determined by UV detection at 295 nm. The mobile phase was acetonitrile-0.05 M ammonium acetate (50:50), and the flow-rate was 0.8 ml/min at 40 degrees C. The mean recoveries (n=4) were 89.1-95.0% with a relative standard deviation of 1.1-2.6%. The detection limits were 0.004-0.006 microg/g in milk. The proposed method was used to monitor raw milk samples for the market, and applied to the analysis of milk samples from 10 cows which had been administered with triclabendazole to control the liver fluke. The confirmation of the triclabendazole and its metabolites in the above milk sample has been achieved by electrospray LC-MS for the first time.

Fungicide residues in vegetables (benomyl, carbendazim, thiabendazole) are analyzed through a clean-up procedure that uses a portion of the aqueous acetone extract prepared for multiresidue methodology. A portion of the aqueous acetone extract (equivalent to 5 g of vegetables) is loaded onto an Extrelut-20 cartridge (the cartridge is filled with a coarse, large-pore diatomaceous material). Then, acetone is partially removed by an upward stream of nitrogen at 2l/min for 30 min. Benzimidazolic fungicides are recovered by percolating the cartridge with 100 ml of 0.1 M phosphoric acid solution, which also serves to convert benomyl to carbendazim. The percolating acid solution is drained on-line through a strong cation-exchange (SCX) solid-phase extraction cartridge with the aid of a slight vacuum. Benzimidazolic fungicides are retained on the SCX cartridge. The phosphoric acid solution is discarded together with the washings of the SCX cartridge, i.e., water followed by methanol-water (75:25), that remove unwanted coextractives. Finally, benzimidazolic fungicides are recovered by eluting the SCX cartridge with methanol-ammonium formate buffer (75:25). The final extract is then analyzed by reversed-phase HPLC with UV detection. Recoveries from crops such as apples, lettuce, strawberries and citrus fruits are generally greater than 80% and no interferences were observed. The clean-up is simple and straightforward, requires only disposable items, water solutions and a few milliliters of solvent and a minimum number of manipulations, and does not require concentration steps or electrical equipment.

Simple methods for the analysis of carbendazim, benomyl and thiophanate methyl in fruits and vegetables and of 2,4-D in citrus fruits are presented. Sample preparation involves supercritical fluid extraction with carbon dioxide and further analysis is performed without any additional clean-up by GC-MS after derivatisation or directly by HPLC-diode array detection. The SFE methods presented are clearly faster and more cost effective than traditional solvent based approaches. The recoveries, detection limits and repeatabilities achieved, meet the needs of tolerance level monitoring of these compounds in fruits and vegetables.

Simple procedures for the extraction and chromatographic determination of benomyl and carbendazim in honey, bees wax, larvae, bees and pollen are proposed. The fungicides were extracted from honey, larvae and bees using ethyl acetate, while methanol was more suitable for wax and pollen samples. Pollen extracts need a further clean-up step with n-hexane. The determination is carried out by reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection. The procedures have been applied to the analysis of benomyl on honey and larvae samples from hives whose bees were nourished with artificial food mixed with benomyl.

A single and simple procedure for the determination of both carbendazim and imazalil is described. The proposed analytical methodology is based on a liquid-liquid extraction with ethyl acetate and further analysis with HPLC-UV in the case of carbendazim, and GC-nitrogen-phosphorus detection in the case of imazalil. Detection levels have been 0.01 mg/kg for carbendazim and 0.005 mg/kg for imazalil. Recoveries have been no less than 77% for carbendazim and 92% for imazalil. The method has been validated with fortified samples at different concentration levels. Different confirmation criteria have been studied and applied in routine analysis. The analytical procedure proposed has been applied to the analysis of 200 fruit samples belonging to the Residue Monitoring of Hygiene Food Program 1995 of the Spanish Ministry of Health, which has been performed in our laboratory. The results obtained have confirmed the viability of the method in routine analysis for these pesticides. A first evaluation of the presence of residues of both fungicides in fruits produced in Spain has been made.

This paper describes the results of a comparison of extraction efficiency between a new polymeric sorbent for solid-phase extraction (SPE) and classical RP-18. Pesticides and their hydrophilic metabolites in the low ppb range have been chosen as target compounds to be extracted from large volume samples. The pesticides were separated using HPLC and detected by diode array detection. Furthermore, a method is presented regarding the determination of carbendazim in water, using SPE on a mixed RP/polymer phase and high-performance liquid chromatography. Recovery, working range, precision and the detection limit are presented.