Enhanced Matrix Removal-Lipid Research Articles

Enhanced Matrix Removal-Lipid (EMR-L): a novel approach for efficient clean-up in systemic toxicological analysis of drugs and pesticides

ABSTRACT The QuEChERS extraction method was extensively modified and validated for effective screening of drugs and pesticides in diverse biological matrices, such as blood, urine, liver, and stomach contents. This method involved the extraction of 2 mL biological samples using acetonitrile as the solvent. To eliminate interferences, particularly lipids, a novel sorbent comprising a combination of C18 and specialized polymers called EMR-L (Enhanced Matrix Removal-Lipid) was employed. The extracted samples were then subjected to analysis using GCMS with a DB-5 MS column. The validation study encompassed various parameters including carryover, limit of detection (LOD), and interference investigation. LOD of analytes were ranged from 0.5 to 1.0 µg/mL. The validated method is known for its simplicity and effectiveness in conducting systemic toxicological analysis, covering a wide range of acidic, neutral, and basic analytes. Moreover, this method has the potential to detect additional drugs and pesticides not included in the validation study, provided they are compatible with gas chromatographic analysis. The modified method was successfully applied to real case samples, proving to be a valuable tool for systemic toxicological analysis. Its versatility allows for the screening of acidic, neutral, and basic drugs and pesticides in various biological matrices.

Development and validation of a modified QuEChERS method for extracting polychlorinated biphenyls and organochlorine pesticides from marine mammal blubber

The monitoring of legacy persistent organic pollutants (POPs) in blubber of key sentinel marine mammal species has been conducted using established techniques for decades. Although these methods for polychlorinated biphenyl (PCB) and organochlorine (OC) pesticide determination provide accurate and reproducible results, they possess some drawbacks in terms of cost, time, and a need for large volumes of toxic solvents. QuEChERS (quick, easy, cheap, effective, rugged, and safe) extractions may help address these issues, but have not been applied to marine mammal blubber/adipose. As such, our aim was to develop, validate, and apply a QuEChERS method for the extraction of PCB and OC contaminants in marine mammal blubber. First, we tested multiple solid-phase extraction and clean-up steps to find the approach that provided the cleanest extracts along with consistent and acceptable analyte recovery, accuracy, and precision. QuEChERS extractions followed by two enhanced matrix removal-lipid (EMR-lipid), one primary-secondary amine (PSA), and one silica gel clean-up showed the highest matrix removal and acceptable recoveries of spiked internal (62–97%) and external standards (61–94%). Solvent usage was reduced by ∼393% and extraction time was reduced by ∼25% (from 16 to 12 h). Next, the method was validated using standard reference material (SRM) NIST 1945. Recovery experiments on SRM (n = 5) showed acceptable recovery for 76% and 77% of PCBs and OC pesticides, respectively, and high precision for 73% and 69% of PCBs and OCs, respectively. Finally, the method was used on a set of southeast Greenland killer whales (n = 13), with previously published PCB and OC data. Bland-Altman plots indicated good agreement between QuEChERS and current-use methods for ΣPCBs and some OCs with no significant constant or proportional bias. These results demonstrate that this QuEChERS extraction method represents an effective, lower cost alternative to current-use extractions for PCBs and OCs in blubber, and likely other high-lipid samples.

Multi-Residue Determination of 244 Chemical Contaminants in Chicken Eggs by Liquid Chromatography-Tandem Mass Spectrometry after Effective Lipid Clean-Up

In this study, we aimed to establish a multi-residue analytical method for the simultaneous detection of chemical contaminants in eggs. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we developed an analytical method that can separate 244 compounds (including β-agonists (25), imidazole and benzimidazoles (31), sulfonamides (22), antihistamines (10), β-lactam (5), insecticides (7), quinolones (24), non-steroidal anti-inflammatory drugs (13), and steroidal hormones (38)) within 30 min. A new enhanced matrix removal-lipid (EMR-Lipid) material was used as a purified sorbent in the QuEChERS clean-up method. Excellent linearity (r > 0.9905) was achieved. Additionally, recoveries ranged between 51.33% and 118.28%, with repeatability (RSDr) and reproducibility (RSDwR) in the range of 1.01–14.22% and 1.08–14.96%, respectively. In all of the compounds, low limits of quantification (LOQs) ≤ 5 μg kg−1 were found. Meanwhile, the detection limit (CCα) and detection capability (CCβ) were 1.88–40.60 μg kg−1 and 2.85–407.19 μg kg−1, respectively. In conclusion, the evaluated method was shown to provide reliable screening, quantification, and identification of 244 multi-class chemicals in eggs and was successfully applied in real samples.

Development and Validation of QuEChERS Followed by UHPLC-ToF-MS Method for Determination of Multi-Mycotoxins in Pistachio Nuts.

Pistachios are one of the types of tree nut fruits with the highest mycotoxin contamination, especially of aflatoxins, worldwide. This study developed a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method that was followed by Ultra-High Performance Liquid Chromatography combined with Time-of-Flight Mass Spectrometry (UHPLC–ToF-MS) for the determination of mycotoxins in pistachios. Different approaches to dispersive solid phase extraction as a clean-up method for high lipid matrices were evaluated. For this, classic sorbents such as C18 (octadecyl-modified silica) and PSA (primary secondary amine), and new classes of sorbents, namely EMR-Lipid (enhanced matrix removal-lipid) and Z-Sep (modified silica gel with zirconium oxide), were used. The QuEChERS method, followed by Z-Sep d-SPE clean-up, provided the best analytical performance for aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZEA), toxin T2 (T2) and toxin HT-2 (HT2) in pistachios. The method was validated in terms of linearity, sensitivity, repeatability, interday precision and recovery; it achieved good results according to criteria imposed by Commission Regulation (EC) no. 401/2006. The method was applied to real samples and the results show that pistachios that are available in Portuguese markets are safe from mycotoxins that are of concern to human health.

Application of d-SPE before SPE and HPLC-FLD to Analyze Bisphenols in Human Breast Milk Samples.

In this study, we propose a simple, cost-effective, and sensitive high-performance liquid chromatography with fluorescence detection (HPLC-FLD) for the simultaneous determination of seven bisphenols (bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB), BADGE (bisphenol A diglycidyl ether), BADGE∙2H2O, BADGE∙H2O, BADGE∙2HCl) in human breast milk samples. The dispersive solid phase extraction (d-SPE) coupled with solid phase extraction (SPE) procedure performed well for the majority of the analytes with recoveries in the range 57–88% and relative standard deviations (RSD%) of less than 9.4%. During the d-SPE stage, no significant matrix effect was observed thanks to the application of different pairs of salts such as zirconium-dioxide-based sorbents (Z-Sep or Z-Sep +) and primary secondary amine (PSA) or QuEChERS Enhanced Matrix Removal-Lipid (EMR-Lipid) and PSA. The method limits of quantification (mLOQs) for all investigated analytes were set at satisfactory low values in the range 171.89–235.11 ng mL−1. Analyte concentrations were determined as the average value from human breast milk matrix samples. The results show that the d-SPE/SPE procedure, especially with the application of EMR-Lipid and PSA, could be used for further bisphenol analyses in human breast milk samples.

Efficient Matrix Cleanup of Soft-Gel-Type Dietary Supplements for Rapid Screening of 92 Illegal Adulterants Using EMR-Lipid dSPE and UHPLC-Q/TOF-MS.

An efficient matrix cleanup method was developed for the rapid screening of 92 illegal adulterants (25 erectile dysfunction drugs, 15 steroids, seven anabolic steroids, 12 antihistamines, 12 nonsteroidal anti-inflammatory drugs (NSAIDs), four diuretics, and 17 weight-loss drugs) in soft-gel-type supplements by ultra-high performance liquid chromatography-quadrupole/time of flight-mass spectrometry (UHPLC-Q/TOF-MS). As representative green chemistry methods, three sample preparation methods (dispersive liquid-liquid microextraction (DLLME), “quick, easy, cheap, effective, rugged, and safe” dispersive solid-phase extraction (QuEChERS-dSPE), and enhanced matrix removal-lipid (EMR-Lipid) dSPE) were evaluated for matrix removal efficiency, recovery rate, and matrix effect. In this study, EMR-Lipid dSPE was shown to effectively remove complicated matrix contents in soft-gels, compared to DLLME and QuEChERS-dSPE. For the rapid screening of a wide range of adulterants, extracted common ion chromatogram (ECIC) and neutral loss scan (NLS) based on specific common MS/MS fragments were applied to randomly collected soft-gel-type dietary supplement samples using UHPLC-Q/TOF-MS. Both ECICs and NLSs enabled rapid and simple screening of multi-class adulterants and could be an alternative to the multiple reaction monitoring (MRM) method. The developed method was validated in terms of limit of detection (LOD), precision, accuracy, recovery, and matrix effects. The range of LODs was 0.1–16 ng/g. The overall precision values were within 0.09–14.65%. The accuracy ranged from 81.6% to 116.6%. The recoveries and matrix effects of 92 illegal adulterants ranged within 16.9–119.4% and 69.8–114.8%, respectively. The established method was successfully applied to screen and identify 92 illegal adulterants in soft-gels. This method can be a promising tool for the high-throughput screening of various adulterants in dietary supplements and could be used as a more environmentally friendly routine analytical method for screening dietary supplements illegally adulterated with multi-class drug substances.

Determination of acetylgestagens in animal-derived matrix samples using enhanced matrix removal lipid clean-up in combination with ultra performance liquid chromatography-tandem mass spectrometry

A robust and confirmative method was established for the determination of six acetylgestagen residues, namely, flurogestone acetate (FGA), megestrol (MA), melengestrol acetate (MGA), chlormadinone acetate (CMA), medroxyprogesterone (MPA), and hydroxyprogesterone acetate (HPA) in animal-derived matrix samples by utilizing enhanced matrix removal lipid (EMR-lipid) clean-up in combination with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The analytes were extracted with acetonitrile, purified with a EMR-lipid cartridge, and separated with a reversed-phase C18 column.The limit of quantification (S/N ≥ 10) for CMA, FGA, HPA, MA, and MGA in all matrices was 0.5 ng/g, and for MPA, it was 1.0 ng/g; the limit of detection (S/N ≥ 3) for CMA, FGA, HPA, MA, and MGA in all matrices was 0.1 ng/g, and for MPA, it was 0.2 ng/g. The recoveries were between 61.0% and 114.8%, and the relative standard deviations (RSDs) were below 12%. The method was calibrated in a matrix-assisted standard solution in various linear ranges for the analytes and matrices, and the correlation coefficients (R2) exceeded 0.99 for all the matrices.

An Optimized Extraction Procedure for Determining Acaricide Residues in Foundation Sheets of Beeswax by Using Gas Chromatography-Mass Spectrometry

Pesticides can be found in beehives for several reasons, including contamination from surrounding cultivars; yet one of the most pertinent is related to the fact that beekeepers employ acaricides to control various types of mites, which may accumulate in beeswax due to their lipophilic nature. In the present study, foundation sheets of different origins, collected over a period of three years, were analyzed to detect the residues of seven acaricides (atrazine, chlorpyrifos, chlorfenvinphos, alpha-endosulfan, bromopropylate, coumaphos, tau-fluvalinate) by gas chromatography with mass spectrometric detection. An efficient sample treatment (recoveries between 90% and 108%) is proposed, involving solvent extraction with 1% acetic acid in acetonitrile mixture followed by dispersive solid-phase extraction (enhanced matrix removal lipid) and a polishing step. An evaluation was made of the analytical performance of the proposed method. It was shown to be selective, linear from a limit of quantification to 5000 µg/kg, precise (relative standard deviation values were below 6%), and with a goo sensitivity (limit of quantification ranging from 5 to 10 µg/kg). Finally, results showed that a large majority of the sheets analyzed (>90%) contained residues of at least one of these compounds. Coumaphos and tau-fluvalinate residues were the most common, with chlorpyrifos and chlorfenvinphos detected to a lesser extent.

Multiresidue determination of 19 anabolic steroids in animal oil using enhanced matrix removal lipid cleanup and ultrahigh performance liquid chromatography-tandem mass spectrometry.

A method for sensitive analysis of 19 anabolic steroids (AS) in animal oil using enhanced matrix removal lipid (EMR-Lipid) cleanup and ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. Oil samples were extracted with 20 mL of acetonitrile aqueous solution and purified using EMR-Lipid cartridges. The eluent was evaporated to dryness under nitrogen and analyzed by UHPLC-MS/MS using 0.1% formic acid-acetonitrile and 0.1% formic acid-water solutions as the mobile phase via gradient elution. The method effectively removed unwanted matrix co-extractives better than other extraction cleanup techniques while still delivering acceptable recovery results for most of the AS. The established quantification method showed AS recovery in the range of 72.9-110.7% with good precision (relative standard deviation < 15%).

Simultaneous Determination of Amitraz and Their Metabolites in Pork and Porcine Liver by Enhanced Matrix Removal-Lipid Column Purified/Liquid Chromatography-Tandem Mass Spectrometry

Simultaneous Determination of Amitraz and Their Metabolites in Pork and Porcine Liver by Enhanced Matrix Removal-Lipid Column Purified/Liquid Chromatography-Tandem Mass Spectrometry

Multi-residue determination of 325 pesticides in chicken eggs with EMR-Lipid clean-up by UHPLC–MS/MS and GC–MS/MS

Eggs are one of the most common foods in the world, and their safety is a major concern for the public. We aimed to develop a novel clean-up approach named Bond Elut Enhanced Matrix Removal-Lipid (EMR-Lipid) for the simultaneous determination of 325 pesticides in the chicken egg by UHPLC–MS/MS and GC–MS/MS. The initial step of extraction was adopted by acetonitrile with 5% formic acid and subsequent adoption of EMR-Lipid d-SPE for further clean-up. Compared with the traditional C18 procedure, EMR-Lipid clean-up achieved a superior degreasing effect. The recoveries of at least 85% of pesticides were in the range of 60–120% at three fortified levels and the relative standard deviation of nearly 96% of analytes were within the limits of criteria. Improved linearity was evaluated using a matrix-matched calibration at eight concentrations in the range 0.1–40 µg/kg; the correlation coefficients of 309 analytes were exceeding 0.99. The new method offered quick, reliable and consistent detection and quantification of 325 pesticide residues, thereby demonstrating promising future for sample testing.

Multi-class multi-residue analysis of pesticides in edible oils by gas chromatography-tandem mass spectrometry using liquid-liquid extraction and enhanced matrix removal lipid cartridge cleanup

This study presents the development and validation of a method for the multi-class multi-residue analysis of pesticide residues in edible oils using liquid-liquid extraction followed by EMR-Lipid (enhanced matrix removal - lipid) cartridge cleanup, and then analyzed by gas chromatography tandem mass spectrometer (GC–MS/MS). The method was optimized for analyte recovery, matrix removal, and water removal during the sample extraction, sample cleanup and sample drying steps. The extraction efficiency of lipophilic pesticides (i.e. organochlorine) from the hydrophobic oil matrix was improved using a two-step liquid-liquid extraction with a mixture of ethyl acetate and acetonitrile. EMR-Lipid cartridges provided efficient and selective cleanup of the tested oil matrices. The developed method was verified by analyzing four edible oil matrices: olive oil, corn oil, soybean oil and canola oil. The results demonstrated that the method effectively removes unwanted matrix co-extractives better than conventional PSA/C18 dispersive solid phase extraction (dSPE) cleanup, while still delivering acceptable recovery results (recoveries of 60–120%) for the majority of pesticides tested. With the established quantification method, over 95% of the pesticides obtained for 70–120% accuracy, RSD < 20%, and calibration curves from 1 to 500 (400) ng/g in oil with R2 > 0.99.

High-throughput gas chromatography-mass spectrometry analysis of pesticide residues in spices by using the enhanced matrix removal-lipid and the sample dilution approach

Spices are known as difficult matrices that contain variable amounts of fats, piperine or many other matrix constituents. The increasing sensitivity of new GC–MS/MS platforms opens new approaches to analyze pesticide residue in complex matrices such as spices, by sample dilution. The aim of this work is to develop and validate an effective multiresidue method for the analysis of pesticide residues in spices by GC–MS/MS. In this paper, we highlight the importance of reducing matrix interferences generated from co-extractive components of spices. Moreover, we emphasize the concern of obtaining clean extracts requiring less instrument maintenance. By evaluating the total ion chromatograms (TIC) on GC-Orbitrap-MS of different extracts using various sorbents, QuEChERS citrate using EMR-Lipid sorbent resulted in the cleanest extract among Z-Sep, Primary secondary amine (PSA), Oasis® Prime HLB, and Supelclean™ Ultra cartridges that consist of a top bed of PSA, C18 and Grashsphere™ 2031 and a bottom bed of Z-Sep. Later, the analyses were performed on a GC-QQQ-MS/MS, applying a 15 min runtime method covering 205 compounds. The samples were diluted 25 times before the injection bearing in mind that the instrumental LOQs reached (iLOQ) were 2 ng g−1 and the method LOQs (mLOQ) were 50 ng g−1. Good recoveries between 70 and 120% with RSDs lower than 20% were observed for 90% of the compounds in black pepper and for 83% of the compounds in cayenne pepper. To demonstrate the applicability of the proposed method, 50 real dried and non-dried spice samples were analyzed. The most detected pesticides were metalaxyl, chlorpyrifos, tebuconazole, ethion, and chinomethionate.

Fast determination of neonicotinoid insecticides in beeswax by ultra-high performance liquid chromatography-tandem mass spectrometry using an enhanced matrix removal-lipid sorbent for clean-up

This study is concerned with the development of a simple, rapid analytical method for simultaneously determining seven neonicotinoid insecticides (dinotefuran, nitenpyram, thiamethoxam, clothianidin, imidacloprid, acetamiprid and thiacloprid) in beeswax, by means of ultra-high performance liquid chromatography coupled to a quadrupole-time-of-flight mass detector. An efficient sample treatment is proposed (with average analyte recoveries between 93% and 106%) involving solvent extraction with a methanol and ethyl acetate mixture (70:30, v/v), centrifugation, freezing with dry ice, a dispersive solid phase extraction (enhanced matrix removal-lipid) followed by evaporation. Chromatographic analysis (10.5 min) was performed on a core-shell technology-based column (Kinetex® EVO C18). The method was fully validated in terms of selectivity, ruggedness, limits of detection (LODs) and quantification (LOQs), matrix effect, linearity, uncertainty, trueness and precision. Low LOQs, ranging from 1.2 to 4.9 μg/kg, were obtained in all cases. Finally, the proposed methods were applied to neonicotinoid analysis of twenty one beeswax samples from different Spanish regions, only one of the pesticides (imidacloprid) being detected at low levels (<LOQ).

Multi-residue pesticide analysis in virgin olive oil by nanoflow liquid chromatography high resolution mass spectrometry

In this article, a nanoflow liquid chromatography system coupled to high resolution mass spectrometry (nanoflow LC/ESI Q-Orbitrap-MS) has been applied for the development of a multiresidue pesticide method for the determination of 162 multiclass pesticides in olive oil samples. Due to the relatively high lipid content of the raw QuEChERS acetonitrile extracts obtained from this type of fatty vegetable samples, a dispersive solid phase extraction (dSPE) sorbent proposed to retain both fatty acids and triglycerides, namely Enhanced Matrix Removal-Lipid (EMR-Lipid) has been implemented as additional cleanup step. The analytical performances of the proposed method were evaluated,achieving recoveries in the range 75–119% with relative standard deviations lower than 19% (n = 6). The dSPE sorbent allowed the removal of most coextracted interferences without a significant loss of analytes. Matrix effects were also evaluated, showing a negligible effect for most of the compounds tested, when a dilution factor of 50 was applied. Notably, despite the use of relatively high dilution factors (e.g. 1:50) to minimize matrix effects, the lowest concentration levels detected with this method – in the low μg kg−1 range – are well below the corresponding maximum residue levels established by the current European legislation.

Multi-class multi-residue analysis of veterinary drugs in meat using enhanced matrix removal lipid cleanup and liquid chromatography-tandem mass spectrometry

This study presents the development and validation of a quantitation method for the analysis of multi-class, multi-residue veterinary drugs using lipid removal cleanup cartridges, enhanced matrix removal lipid (EMR-Lipid), for different meat matrices by liquid chromatography tandem mass spectrometry detection. Meat samples were extracted using a two-step solid-liquid extraction followed by pass-through sample cleanup. The method was optimized based on the buffer and solvent composition, solvent additive additions, and EMR-Lipid cartridge cleanup. The developed method was then validated in five meat matrices, porcine muscle, bovine muscle, bovine liver, bovine kidney and chicken liver to evaluate the method performance characteristics, such as absolute recoveries and precision at three spiking levels, calibration curve linearity, limit of quantitation (LOQ) and matrix effect. The results showed that >90% of veterinary drug analytes achieved satisfactory recovery results of 60–120%. Over 97% analytes achieved excellent reproducibility results (relative standard deviation (RSD) < 20%), and the LOQs were 1–5 μg/kg in the evaluated meat matrices. The matrix co-extractive removal efficiency by weight provided by EMR-lipid cartridge cleanup was 42–58% in samples. The post column infusion study showed that the matrix ion suppression was reduced for samples with the EMR-Lipid cartridge cleanup. The reduced matrix ion suppression effect was also confirmed with <15% frequency of compounds with significant quantitative ion suppression (>30%) for all tested veterinary drugs in all of meat matrices. The results showed that the two-step solid-liquid extraction provides efficient extraction for the entire spectrum of veterinary drugs, including the difficult classes such as tetracyclines, beta-lactams etc. EMR-Lipid cartridges after extraction provided efficient sample cleanup with easy streamlined protocol and minimal impacts on analytes recovery, improving method reliability and consistency.

Determination of 39 veterinary drug residues in Procambarusclarkii by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry

An ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) method was developed for determination of 39 veterinary drugs in Procambarusclarkii. Samples were extracted with acidified acetonitrile and purified with enhanced matrix removal-lipid (EMR-Lipid) adsorbent and graphitized multi-walled carbon nanotubes (GMWNTs). Extracts were analyzed by UHPLC-Q-TOF-MS. Target compounds were screened according to accurate mass, isotopic ratio, and retention time, and confirmed by library search. Target analytes were quantified using the chromatographic peak area of each compound. For each of the drugs of interest, calibration curves were linear in their respective ranges with correlation coefficients greater than 0.99. The limits of quantification (LOQs) were 3-15 μg/kg. The recoveries for target compounds spiked in Procambarusclarkii ranged from 62.4% to 105.8%, with relative standard deviations (RSDs) ranging from 2.5% to 13.5%. This method is simple, rapid, accurate, and suitable for simultaneous determination of 39 veterinary drugs, including sulfonamides, quinolones, and triphenylmethane, extracted from Procambarusclarkii.

Evolution of novel sorbents for effective clean-up of honeybee matrix in highly toxic insecticide LC/MS/MS analysis

Highly toxic insecticides (HTIs) belonging to different chemical groups are dangerous to pollinating organisms, even in sublethal doses. An important objective of this study was to develop a method to determine over fifty HTIs at very low concentrations in the bee matrix. The novelty of this research involved obtaining extract completely free from beewaxes, lipids and proteins using EMR-lipid (enhanced matrix removal-lipid), chitin and Z-Sep+ (zirconium oxide and C18 dual-bonded to silica) as clean-up sorbents. Different parameters, such as weight of bees, extraction solvent, and freezing time were evaluated. Determinations were made using liquid chromatography-tandem mass spectrometry (LC-MS/MS). EMR-lipid allows for removing most of the fatty co-extracts and increases the overall performance of the method by reducing the matrix effects (ME) without significant analyte loss. The established modified QuEChERS method based on 1% acetic acid in acetonitrile extraction followed by EMR-lipid clean-up was validated at three different spiking levels (0.001, 0.01 and 0.1mgkg−1). Precision, calculated as relative standard deviation (RSD), was below 20%. The proposed method was used to determine sublethal doses of these insecticides in real samples of dead honeybees.

Large multiresidue analysis of pesticides in edible vegetable oils by using efficient solid-phase extraction sorbents based on quick, easy, cheap, effective, rugged and safe methodology followed by gas chromatography–tandem mass spectrometry

The aim of this research was to adapt the QuEChERS method for routine pesticide multiresidue analysis in edible vegetable oil samples using gas chromatography coupled to tandem mass spectrometry (GC–MS/MS). Several clean-up approaches were tested: (a) D-SPE with Enhanced Matrix Removal-Lipid (EMR-Lipid™); (b) D-SPE with PSA; (c) D-SPE with Z-Sep; (d) SPE with Z-Sep. Clean-up methods were evaluated in terms of fat removal from the extracts, recoveries and extraction precision for 213 pesticides in different matrices (soybean, sunflower and extra-virgin olive oil). The QuEChERS protocol with EMR-Lipid d-SPE provided the best reduction of co-extracted matrix compounds with the highest number of pesticides exhibiting mean recoveries in the 70–120% range, and the lowest relative standard deviations values (4% on average). A simple and rapid (only 5min) freeze-out step with dry ice (CO2 at −76°C) prior to d-SPE clean-up ensured much better removal of co-extracted matrix compounds in compliance of the necessity in routine analysis. Procedural Standard Calibration was established in order to compensate for recovery losses of certain pesticides and possible matrix effects. Limits of quantification were 10μgkg−1 for the majority of the pesticides. The modified methodology was applied for the analysis of different 17 oil samples. Fourteen pesticides were detected with values lower than MRLs and their concentration ranged between 10.2 and 156.0μgkg−1.

Determination of pesticides in edible oils by liquid chromatography-tandem mass spectrometry employing new generation materials for dispersive solid phase extraction clean-up

The goal of this work was to evaluate the efficiency of several sorbents on removal fats from edible oils (olive, soya and sunflower) during the clean-up step for posterior determination of 165 pesticides by UHPLC-QqQ-MS/MS system. The extraction procedure employed in this work was the citrate version of QuEChERS method followed by a step of freezing out with dry ice and clean-up evaluation using i) PSA with magnesium sulfate (d-SPE); ii) magnesium sulfate and Z-sep sorbent (d-SPE); iii) Z-sep (column SPE) and iv) Agilent Bond Elut QuEChERS Enhanced Matrix Removal-Lipid (EMR-Lipid). After evaluation of the recovery results at 10, 20 and 50μgkg−1, the EMR-Lipid showed important advantages comparing to the other sorbents evaluated, such as better recovery rates and RSD%. The method was validated at the three concentrations described above. Analytical curves linearity was evaluated by spiking blank oil samples at 10, 20, 50, 100 and 500μgkg−1. The method demonstrated good recoveries values between the acceptable range of 70–120% and RSD%<20 for most of evaluated pesticides. In order to evaluate the performance of the method, this same procedure was employed to other oils such as soya and sunflower with very good results.