Multiresidue Pesticide Analysis of Dried Botanical Dietary Supplements Using an Automated Dispersive SPE Cleanup for QuEChERS and High-Performance Liquid Chromatography-Tandem Mass Spectrometry
ABSTRACT An automated dispersive solid phase extraction (dSPE) cleanup procedure as part of the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method, coupled with liquid chromatography-tandem mass spectrometry using electrospray ionization in positive mode, was used for the simultaneous analysis of 236 pesticides in three dried powdered botanical dietary supplements (ginseng, saw palmetto, and gingko biloba). The procedure involved extraction of the dried powdered botanical samples with salt-out acetonitrile/water extraction using anhydrous magnesium sulfate and sodium chloride, followed by an automated dSPE cleanup using a mixture of octadodecyl- (C(18)) and primary-secondary amine (PSA)-linked silica sorbents and anhydrous MgSO(4) and online LC-MS/MS analysis. Dynamic multiple-reaction monitoring (DMRM) based on the collection of two precursor-to-product ion transitions with their retention time windows was used for all of the targeted pesticides and the internal standard. Matrix-matched calibration standards were used for quantitation, and standard calibration curves showed linearity (r(2) > 0.99) across a concentration range of 0.2-400 ng/mL for the majority of the 236 pesticides evaluated in the three botanical matrices. Mean recoveries (average %RSD, n = 4) were 91 (6), 93 (4), 96 (3), and 99 (3)% for ginseng, 101 (9), 98 (6), 99 (4), and 102 (3)% for gingko biloba, and 100 (9), 98 (6), 96 (4), and 96 (3)% for saw palmetto at fortification concentrations of 25, 100, 250, and 500 μg/kg, respectively. The geometric mean matrix-dependent instrument detection limits were 0.17, 0.09, and 0.14 μg/kg on the basis of the studies of 236 pesticides tested in ginseng roots, gingko biloba leaves, and saw palmetto berries, respectively. The method was used to analyze incurred ginseng samples that contained thermally labile pesticides with a concentration range of 2-200 μg/kg, indicating different classes of pesticides are being applied to these botanicals other than the traditional pesticides that are commonly used and analyzed by gas chromatography techniques. The method demonstrates the use of an automated cleanup procedure and the LC-MS/MS detection of multiple pesticide residues in dried, powdered botanical dietary supplements.
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ABSTRACT: Microwave Assisted Extraction and a modified CEN-QuEChERS methodology were evaluated as extraction and clean up procedures for the simultaneous analysis of 42 organophosphate pesticides in yerba mate (Ilex paraguaiensis). The obtained extracts were analyzed by gas chromatography using a flame photometric detector. Linearity, recovery percentages, relative standard deviations, detection and quantification limits and matrix effects were determined according to DG-SANCO guidelines for both methods. At 0.2 and 0.5 mg/kg the evaluated methods showed percentages recoveries between 70 and 120% for most of the analytes. Using Microwave Assisted Extraction methodology, 33 pesticide residues could be properly analyzed whereas only 27 could be determined with the proposed modified QuEChERS. All relative standard deviation were below 18% except for omethoate and disulfoton sulfone when evaluated by the modified QuEChERS. The limits of detection in both methodologies were 0.2 mg/kg for most of the analyzed compounds. The average detection limit for QuEChERS was 0.04 mg/kg. For 19 of the analytes determined through Microwave Assisted Extraction the lowest validated level were 0.004 mg/kg. Signal suppression/enhancement was observed for most of the pesticides, thus matrix-matched calibration curves were used for quantification. The Microwave Assisted Extraction and QuEChERS procedures studied could detect the organophosphate pesticides above the MRL fixed for “mate” by the European Union. They have been successfully applied for the determination of organophosphate pesticide residues in commercial samples and the positives were confirmed through GC–(ITD)-MS.Revista Brasileira de Farmacognosia 03/2015; 86. DOI:10.1016/j.bjp.2015.02.001 · 0.80 Impact Factor
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ABSTRACT: An analytical method based on a modified QuEChERS extraction coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) was evaluated for the determination of 177 pesticides in soya-based nutraceutical products. The QuEChERS method was optimised and different extraction solvents and clean-up approaches were tested, obtaining the most efficient conditions with a mixture of sorbents (PSA, C18, GBC and Zr-Sep(+)). Recoveries were evaluated at 10, 50 and 100μg/kg and ranged between 70% and 120%. Precision was expressed as relative standard deviation (RSD), and it was evaluated for more than 160 pesticides as intra and inter-day precision, with values always below 20% and 25%, respectively. Limits of detection (LODs) ranged from 0.1 to 10μg/kg, whereas limits of quantification (LOQs) from 0.5 to 20μg/kg. The applicability of the method was proved by analysing soya-based nutraceuticals. Two pesticides were found in these samples, malathion and pyriproxyfen, at 11.1 and 1.5μg/kg respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.Food Chemistry 04/2015; 173:796-807. DOI:10.1016/j.foodchem.2014.10.100 · 3.26 Impact Factor
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ABSTRACT: More than 250 toxic substances, including pesticides and mycotoxins, have been identified and quantified in ginkgo biloba nutraceutical products using liquid chromatography (LC) coupled to high resolution mass spectrometry (Exactive-Orbitrap). A “dilute and shoot” procedure, using acetonitrile with formic acid (1% v/v), was applied for the extraction of the target compounds. In this case, after this procedure, a clean-up step was necessary using a mixture of sorbents (PSA, GBC, C18 and Z-Sep+). Parameters such as trueness, repeatability, intermediate precision, limits of detection and quantification were evaluated. Recoveries between 70 and 120% with relative standard deviation (RSD) values lower than 20% were obtained for 260 of the compounds. Limits of detection and quantification below 5 and 10 μg kg− 1 were obtained, respectively. Nine samples of ginkgo biloba nutraceutical products were analyzed, finding pesticides in 8 out of 9 samples, such as hymexazol (10 μg kg− 1) and tebufenozide (55–459 μg kg− 1). In the case of mycotoxins, aflatoxin B1 (5–54 μg kg− 1), aflatoxin B2 (4–300 μg kg− 1) and T-2 toxin (18–20 μg kg− 1) were found in 6 samples.Microchemical Journal 01/2015; 118:124–130. DOI:10.1016/j.microc.2014.09.002 · 3.58 Impact Factor