A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1). 相似文献
ABSTRACTA method for the simultaneous determination of 30 pesticides residues in soil was developed and validated. Among the studied agrochemicals, there are herbicides (auxines, sulfonylureas, fops, imidazolinones), fungicides (azoles) and insecticides (organophosphorus) widely used in extensive agricultural activities in Uruguay. Five methods with different extraction times, type and amount of solvent, as well as the possibility of a clean-up step were compared in terms of percentage of recovery and repeatability. The final method was based on the extraction of the pesticides’ residues from soil using two successive solvent extraction steps. First, the soil was extracted with methanol in an orbital shaker for 4 h. Secondly, the solid residue was re-extracted overnight with ultrapure water. The methanolic extract was concentrated under vacuum, whereas the aqueous solution was passed through an OASIS HLB® cartridge, eluted with an appropriate solvent and concentrated under nitrogen stream. Both extracts were finally combined and analysed by LC-QQQ-MS/MS using the Document SANTE/11,945/2015 criteria. Recovery percentages at 1 and 10 μg kg?1 for the studied compounds were in the range 70106% with relative standard deviations below 19 %. The quantification was performed using matrix-matched calibration curves as some compounds presented very strong signal suppression. Residuals of the matrix-matched calibration curves were below 20% for all the validated analytes. The quantification limit was1 μg kg?1. The method also allows the screening of 11 pesticides in soil. Sixty-five real samples collected from regions where the use of pesticides is intensive were analysed. Quinclorac, tebuconazole, penoxsulam and clomazone were the most frequently pesticides detected. 相似文献
Four different extraction and clean-up protocols based on the QuEChERS method were compared for the development of an optimized sample preparation procedure for the multiresidue analysis of 16 commonly applied herbicides in rice crops using LC-QqQ/MS. Additionally the methods were evaluated for the analysis of 26 insecticides and fungicides currently used in rice crops. The methods comprise, in general, the hydratation of the sample with water followed by the extraction with acetonitrile, phase separation with the addition of different salts and finally a clean-up step with various sorbents.Matrix effects were evaluated for the 4 studied methods using LC-QqQ/MS. Additionally LC-TOF/MS was used to compare the co-extractants obtained with the four assayed methodologies. Thirty-six pesticides presented good performance with recoveries in the range 70-120% and relative standard deviations below 20% using 7.5 g of milled polished rice and the buffered acetate QuEChERS method without clean-up at both fortification levels: 10 and 300 μg kg−1. The other six pesticides presented low recovery rates, nevertheless all these analytes could be analyzed with at least one of the other three studied procedures. 相似文献
The optimization and validation study of a qualitative and quantitative multiclass, ethyl acetate (EtOAc) multi-residue method to straightforward monitor 48 compounds in liver (6 veterinary drugs and 42 pesticides) and 54 in muscle (5 veterinary drugs and 49 pesticides) followed by high performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS) and gas chromatography mass-spectrometry determination (GC–MS) is presented. Several clean-up sorbents were evaluated looking for the best strategy for the removal of the matrix co-extractives. A combination of aluminium oxide, (Al2O3), C-18 and magnesium sulphate (MgSO4) yielded the best analytical results in terms of precision and accuracy. The method was validated at three fortification levels: 10, 100 and 250 µg kg−1. The percentages of recovery were between 70 and 114 % for bovine muscle and 70–118 % for liver. Repeatability and intermediate precision percentages were below 20 % for both matrices. Most of the compounds under study presented good linearity and quantification limits below their corresponding European Union (EU) and Codex Alimentarius maximum residue levels (MRLs). Twenty-two randomly taken real samples were analyzed with the validated methodology, trying to prove its effectiveness and suitability for routine analysis. The validated methodology represents a fast and cheap alternative for the simultaneous analysis of pesticides and veterinary drugs which can be easily extend to other compounds and matrices.
During spring 2012, massive honeybee mortality was observed within 2000 beehives in southwest Uruguay. The incident was presumed to be due to pesticide applications in the hives surroundings. To find the causative agent, bees were analyzed by gas and liquid chromatography coupled t
o mass spectrometry, employing a method reported by our group that has been expanded to 39 compounds. The new scope includes parathion-methyl, which was found at an average 0.48 µg bee−1, ten times higher than the LD50 for bees. Parathion-methyl is only allowed to be sold as microcapsules, a slow release formulation type with 80–50 µm particle diameter. Surprisingly, it was stated that parathion-methyl microcapsules were applied in the zone but 1000–2000 m ahead from the affected hives. This fact was not only a confirmation of the distances bees can fly from the hive, but also demonstrated that the microcapsules, mistaken for pollen, were transported to the hive where the toxic was released. Although microcapsules have environmental advantages as a pesticide delivery system they can threaten honeybees’ survival.
Marijuana (non-medical cannabis) is a well-recognized psychoactive herbal drug used for recreational purposes. The aim of this work is to describe and compare the performance and suitability of selected methods to analyze pesticide residues in marijuana. The fitness of three typical pesticide multiresidue methods [acetate buffered QuEChERS (method A), a modified citrate buffered QuEChERS (method B) and citrate buffered QuEChERS (method C)] were tested in marijuana through the LC–MS/MS determination of 61 LC amenable pesticides. Considering recoveries at the highest level for the selected pesticides in marijuana, from the 61 target analytes, 37 (method A), 40 (method B) and 46 (method C) compounds gave accurate results (70–120 % range). Method C showed the best performance for the target analytes in terms of recoveries, precision, limits of quantitation and matrix effect. Marijuana showed to be a highly complex matrix. Most analytes suffered high signal suppression (ME <−50 %) for method B while medium (−50 to 20 %) to low (−20 to 0 %) signal suppression was found for methods A and C. Moreover, high coelution of coextractives with the target analytes was observed. A pilot survey with real samples revealed that seized and legally produced marijuana samples contained pesticides. Residues of diazinon (0.03 mg kg−1), tebuconazole (0.19 mg kg−1) and teflubenzuron (0.11 mg kg−1) were simultaneously detected in one marijuana sample. The establishment of MRLs in a legal consumption scenario such as in Uruguay seems to be necessary in the near future.
