Primary Secondary Amine Sorbent Research Articles

Dynamic headspace GC-MS/MS analysis of ethylene oxide and 2-chloroethanol in dry food commodities: a novel approach

With frequent RASFF notifications from the EU countries, the residue testing of ethylene oxide (EtO) and its metabolite 2-chloroethanol (2-CE) in food commodities has become essential to check their compliance with MRLs. This study, for the first time, aimed at establishing a dynamic headspace-GC-MS/MS method for the simultaneous determination of these two analytes in acetonitrile extracts of cumin, ashwagandha, chilli powder, turmeric powder, guar gum, locust bean gum, and ginger powder. The samples (4 g) were extracted using acetonitrile (10 mL). A dispersive-solid phase extraction cleanup step with primary secondary amine sorbent (50 mg/mL) reduced the interfering signal of (matrix-derived) acetaldehyde by >40% in chilli powder, ginger, turmeric, and guar gum. This cleanup was not required for sesame seeds. With high selectivity and sensitivity, the GC-MS/MS approach identified and quantified both compounds simultaneously. At the spiking levels of 0.01, 0.02, and 0.05 mg/kg, the recoveries and precision were satisfactory (70–120%, RSDs, ≤15%). The headspace method-performance was similar to liquid injections. The method provided reproducible results when evaluated by two different laboratories. The method provided high-precision results for incurred residue analysis. Given its efficiency, the validated method is anticipated to improve the effectiveness of monitoring of EtO residues in food commodities.

Development and Validation of a Residue Analysis Method for Ethylene Oxide and 2-Chloroethanol in Foods by Gas Chromatography Tandem Mass Spectrometry

A selective and sensitive method is reported for the residue analysis of ethylene oxide (EO) in diverse matrices, namely sesame, cumin, wheat, tea, spices, herbs, dehydrated fruits, food additives, grapes, and tomatoes. The study modified the European Union reference method (EN 15662) by performing the sample extraction (with acetonitrile) at <10 °C, cleanup through dispersive-solid phase extraction with C18 and primary secondary amine sorbents, and analysis using gas chromatography tandem mass spectrometry with selected reaction monitoring. Injections were performed through a programmable temperature vaporizer port. The sample preparation process provided a limit of quantification of 10 ng/g for both EO and 2-CE and effectively minimized matrix effects. Recoveries of both EO and 2-CE ranged from 74 to 120% at 10, 20, and 50 ng/g with precision RSDs of <12%, satisfying the SANTE/11312/2021 guidelines of analytical method validation. The HorRat (Horwitz ratio) values of 0.31–0.40 indicated high interlaboratory (n = 6 laboratories) method reproducibility. The results of incurred residues in sesame (0.055–0.1 mg/kg), cumin (0.008–0.013 mg/kg), and coriander (0.01–0.025 mg/kg) demonstrated satisfactory extraction efficiency and precision (RSDs < 10%) in test results. The method is highly suitable for regulatory analysis of EO in diverse food matrices.

A modified QuEChERS method development to analyze tylosin and metronidazole antibiotics residue in shrimp (Penaeus monodon) using LC-ESI MS/MS

A modified QuEChERS method was developed for the simultaneous analysis of tylosin (Tyl) and metronidazole (MNZ) residues in shrimp samples using LC-ESI-MS/MS. The sample extraction procedure was based on modified QuEChERS, and the cleanup method was dispersive solid-phase extraction (dSPE). Octadecyl (C18) and primary secondary amine (PSA) sorbents were used in the dSPE cleanup. Analyte chromatographic separations were carried out using a ZORBAX RRHD Eclipse Plus C18 (100 × 2.1 mm, particle size 1.8 μm) column. The mobile phase consisted of dilluting 0.1% of formic acid with water and acetonitrile. The analyte was identified with multiple reaction monitoring and positive electrospray ionization. The analyte showed good linearity in the range of 0.5–50 μg/L for both analytes, and correlation coefficients (R2) were 0.9997 and 0.9998 for Tyl and MNZ, respectively. For the recovery study, three different concentration levels were spiked in triplicate. The recovery obtained a good result in the range of 81–85 % for Tyl with relative standard deviation (RSD) ≤ ± 4.9% and in the range of 85–88% for MNZ with RSD ≤ ± 4.07 %. The limit of detection (LOD) was estimated at 0.4 μg/kg for Tyl and 0.3 μg/kg for MNZ, and the limit of quantification (LOQ) was estimated at 1 μg/kg for Tyl and 0.9 μg/kg for MNZ. The linearity and recovery study showed that the method is validated and can be used to determine the Tyl and MNZ residues in shrimp. Finally, the method was applied to 25 real samples, which were collected from local markets and super shops in Dhaka and Khulna districts of Bangladesh, and only traces of Tyl were detected in one sample. This method is suitable for the regular analysis of Tyl and MNZ antibiotic residues in shrimp samples and can be used to ensure food safety in Bangladesh.

Evaluation of a septumless mini-cartridge for automated solid-phase extraction cleanup in gas chromatographic analysis of >250 pesticides and environmental contaminants in fatty and nonfatty foods

The QuEChERSER mega-method has recently been introduced to quantify and identify a wide range of chemical residues (pesticides, veterinary drugs, environmental contaminants, among others) in nearly all types of foods. The approach calls for taking a small amount of the initial extract to cover analytes amenable to liquid chromatography, and the remainder is salted out for analysis by gas chromatography (GC), both with mass spectrometry (MS) based detection. In the case of GC-MS(/MS), the extract undergoes automated robotic mini-cartridge solid-phase extraction (SPE) cleanup in a technique known as µSPE or instrument-top sample preparation (ITSP). In 2022, a septumless mini-cartridge for µSPE was introduced to improve upon the ITSP design. The new design houses a bed of 20 mg anhydrous MgSO4, 12 mg each of C18 and primary secondary amine sorbents, and 1 mg of graphitized carbon black, the latter substituting for CarbonX used in the ITSP product. The septumless µSPE mini-cartridge employs a different gripping mechanism with the syringe needle that allows leak-free operation at higher flow rates (e.g. 10 µL/s), whereas the ITSP design is limited to 2 µL/s. Based on cleanup and analyte elution profiles, the extract load volume and flow rate was increased in µSPE for QuEChERSER from 300 µL at 2 µL/s to 500 µL at 5 µL/s, which improved accuracy of results, sped the cleanup step, and obviated the need for micro-vial inserts in the receiving vials. The new design also reduced both the amount and consistency of dead (void) volumes in the mini-cartridges from 83 ± 14 µL to 52 ± 7 µL for 200-600 µL load volumes. Normalization of peak areas to internal standards led to recoveries between 80 and 120% with typical RSDs <5% in low-pressure GC-MS/MS of 227-242 out of 252 pesticides, polychlorinated biphenyls, polybrominated diphenyl ethers, and polycyclic aromatic hydrocarbons in hemp powder, spinach, whole milk, egg, avocado, and lamb meat.

Combination of mixed mode dispersive solid phase extraction with magnetic ionic liquids based dispersive liquid–liquid microextraction for the extraction of anticoagulant drugs from urine samples

In this report, combination of a mixed mode dispersive solid phase extraction with dispersive liquid–liquid microextraction has been performed in order to the effective isolation of three anticoagulant drugs (anagrelide, betrixaban, and apixaban) from urine sample. The extracted drugs were quantified by high performance liquid chromatography–diode array detector. Firstly, analytes were adsorbed onto a mixture of octadecylsilane, graphitized carbon black, and primary secondary amine sorbents which their composition was obtained by a simplex centroid design. To increase the adsorption efficiency, sonication of the solution and sorbents mixture was performed. The loaded analytes onto the sorbent surface were washed employing a water–miscible organic solvent which was utilized as a disperser in microextraction process. The microextraction step was done using a magnetic ionic liquid (as an extractant) and the droplets were sedimented at the bottom of tube with the aid of an external magnetic field. Satisfactory analytical results such as wide linear ranges (0.21–250 µg/L), high enrichment factors (223–247) and extraction recoveries (76–84 %), and low limits of detection (0.04–0.06 µg/L) and quantification (0.16–0.21 µg/L) were obtained using the optimum experimental situations. Lastly, the offered procedure was utilized for the quantification of the opted analytes in urine samples.

Multi-residue determination of bisphenol analogues in organism tissues by ultra-high performance liquid chromatography-tandem mass spectrometry

A reliable and sensitive analyzing method was developed and validated for determination of 13 novel bisphenol analogues (BPs) along with bisphenol A (BPA) in organism tissues. The complex organism tissues were treated by ultrasonic-assisted extraction using acetonitrile/formic acid (99:1, v/v), followed by successive purification using enhanced matrix removal-lipid sorbents and primary secondary amine sorbents. The BPs were finally determined by ultra-high performance liquid chromatography-tandem mass spectrometry after derivatization using pyridine-3-sulfonyl chloride. Satisfactory recoveries of 75 - 118% were obtained for the BPs, with good repeatability (RSD < 20%). Matrix interferences were efficiently diminished. The method quantification limits (MQLs) reached 0.003 - 0.1 ng g−1 dry weight (dw). The validated method was successfully applied to a preliminary investigation of the BPs in wild marine organisms collected from the nearshore waters along the coast of Guangdong, China. Besides BPA, novel BPs such as bisphenol F, bisphenol AF, and tetrabromobisphenol A were also detected at < MDL - 15.5 ng g−1 dw. This work laid a strong basis for further in-depth research on bioaccumulation of the novel BPs in the environment.

[Determination of five nitroimidazoles and six benzodiazepines in aquatic products using ultra-high performance liquid chromatography-tandem mass spectrometry coupled with dispersive solid-phase extraction].

建立了分散固相萃取-超高效液相色谱-串联质谱法同时测定水产品中5种硝基咪唑类和6种苯二氮卓类药物残留的方法。样品用1%(v/v)氨水乙腈提取,提取液经十八烷基键合硅胶(C18)和N-丙基乙二胺(PSA)吸附剂净化,在45 ℃下用氮气吹至近干,用1 mL甲醇-水(1:9, v/v)溶液复溶,过0.22 μm尼龙-66滤膜后用超高效液相色谱-串联质谱测定。目标化合物采用Kinetex F5色谱柱(100 mm×3.0 mm, 2.6 μm)分离,以0.1%(v/v)甲酸水溶液和甲醇作为流动相进行梯度洗脱,在电喷雾离子源(ESI)、正离子扫描和多反应监测(MRM)模式下进行测定,基质匹配外标法定量。结果表明,5种硝基咪唑类和6种苯二氮卓类药物在8.5 min内完成色谱分离分析,目标物在0.5~20 μg/L范围内线性关系良好,相关系数均大于0.995,检出限和定量限分别为0.2~0.5 μg/kg和0.5~1.0 μg/kg。以草鱼、对虾和大黄鱼为样品基质,在3个不同的添加水平下,5种硝基咪唑类和6种苯二氮卓类药物的平均回收率为73.2%~110.6%,相对标准偏差(RSD)小于15%。本研究建立的方法具有简单、快速、灵敏度高和成本低等优势,可用于水产品中5种硝基咪唑类和6种苯二氮卓类药物的快速检测。该方法的建立为我国水产品质量安全相关监管部门同时监控水产品中硝基咪唑类和苯二氮卓类药物残留提供了技术支持。

Activation of the xenobiotic metabolism and oxidative stress response by mixtures of organic pollutants extracted with in-tissue passive sampling from liver, kidney, brain and blubber of marine mammals.

We used in-tissue passive equilibrium sampling using the silicone polydimethylsiloxane (PDMS) to transfer chemical mixtures present in organs from marine mammals with lipid contents between 2.3 and 99%into in vitro bioassays. Tissues from five harbor porpoises (Phocoena phocoena), one harbor seal (Phoca vitulina) and one orca (Orcinus orca) from the North and Baltic Seas were sampled until thermodynamic equilibrium was reached. Mixture effects were quantified with cellular reporter gene bioassays targeting the activation of the aryl hydrocarbon receptor (AhR-CALUX), the peroxisome proliferator-activated receptor gamma (PPARγ-bla) and the oxidative stress response (AREc32), with parallel cytotoxicity measurements in all assays. After removing co-extracted lipids and other matrix residues with a non-destructive cleanup method (freeze-out of acetonitrile extract followed by a primary secondary amine sorbent extraction), the activation of the PPARγ and AREc32 were reduced by factors of on average 4.3±0.15 (n=22) and 2.5±0.23 (n=18), respectively, whereas the activation of the AhR remained largely unaltered: 1.1±0.075 (n=6). The liver extracts showed the highest activation, followed by the corresponding kidney and brain extracts, and the blubber extracts of the animals were the least active ones. The activation of the PPARγ by the liver extracts was reduced after cleanup by a factor of 11±0.26 (n=7) and the AREc32 activity by a factor of 1.9±0.32 (n=4). The blubber extracts did not activate the AhR up to concentrations where cytotoxicity occurred or up to an acceptable lipid volume fraction of 0.27% as derived from earlier work, whereas all liver extracts that had undergone cleanup activated the AhR. The developed in-tissue passive sampling approach allows a direct comparison of the bioassay responses between different tissues without further normalization and serves as a quantitative method suitable for biomonitoring of environmental biota samples.

[Fast screening and confirmation of 73 common prohibited compounds in cosmetics by ultra performance liquid chromatography-quadrupole-time-of-flight high resolution mass spectrometry].

建立了超高效液相色谱-四极杆-飞行时间高分辨质谱(UPLC-Q-TOF HRMS)同时快速筛查确证化妆品中73种常见禁用物质的方法。样品经饱和氯化钠溶液分散均匀后,采用含0.2%甲酸的乙腈溶液超声提取,50 mg PSA净化,以8000 r/min高速冷冻离心除脂,采用Waters Acquity HSS T3色谱柱(100 mm×2.1 mm, 1.8 μm)分离。采用多反应监测高分辨扫描模式(MRM HR),以保留时间、一级母离子精确质量数、同位素丰度比和二级子离子精确质量数实现化妆品中73种禁用物质的快速筛查和确证,基质匹配外标法定量。实验比较了不同提取溶剂、净化吸附剂、色谱条件和质谱扫描模式对73种禁用物质测定的影响,并考察了膏霜剂和水剂的基质效应。结果表明,73种禁用物质线性关系良好,相关系数(R2)>0.99;检出限为5~150 μg/kg;定量限为15~450 μg/kg;膏霜剂及水剂两种基质在3个加标水平下的回收率为60.3%~130.3%,日内、日间RSD分别为0.8%~10.0%(n=6)和1.1%~15.0%(n=3)。日常风险监测中检出磺胺甲基异噁唑、甲基泼尼松、林可霉素、对乙酰氨基酚、甲氧苄啶、阿法骨化醇、倍他米松戊酸酯、溴莫尼定、氯霉素、氯苯那敏、氯倍他索丙酸酯、克罗米通、益康唑、酮康唑、泼尼松醋酸酯和泼尼松,检出含量范围为0.5~1136.1 mg/kg。该方法准确、快速、简便,可用于化妆品中73种常见禁用物质的检测。

Research of the determination method of furfurals and furosine in milk and the application in the quality evaluation of milk

The heat treatment process usually affects the quality and safety of milk and could produce different compounds, including furosine and furfurals. To help evaluate the effect of different heating temperatures on furfurals, a method based on gas chromatography-mass spectrometry (GC-MS) combined with QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction technology was used to detect four furfural compounds, including furfural, 2-acetylfuran, 5-methyl-2-furfural, and 5-hydroxymethyl-2-furfural. A sample extraction was performed with acetonitrile, and the use of both octadecylsilyl (C18) and primary secondary amine (PSA) sorbents can provide satisfactory recoveries. The determination of furosine was performed by using a high performance of liquid chromatography method (HPLC), and the milk samples were hydrolyzed with HCl for 18 h at 110°C. Under the optimized conditions, good linearity was obtained with linear correlation coefficients (R2) above 0.99, and the recovery values from the spiked samples were 88.1–109.5%. The limits of detection were in the range of 0.005 mg/kg–0.015 mg/kg. The established GC-MS and HPLC methods were successfully applied to market milk samples and heat-treatment samples. The highest detection values for 5-hydroxymethyl-2-furfural and furosine were 0.051 mg/kg and 593.2 mg/100 g protein, respectively, in charcoal-flavored fermented milk. It showed a high correlation between the formation of 5-hydroxymethyl-2-furfural with the treatment temperature and time, and the maximum content was 0.886 mg/kg after heating for 180 min at 100°C. However, there was no noticeable linear increase of furosine concentrations when certain temperatures and heating times were reached; the maximum value was 55.0 mg/L after heating for 60 min at 100°C, and 55.4 mg/L after heating for 150 min at 80°C.

Dissipation and dietary risk assessment of carbendazim and epoxiconazole in citrus fruits in China.

Carbendazim and epoxiconazole are widely applied to control anthracnose and sand bark fungal diseases in citrus. The residues of these two fungicides in citrus and their potential risk to consumers have generated much public concern. We therefore sought to investigate the dissipation, residue, and dietary risk assessment of carbendazim and epoxiconazole in citrus. The dissipation kinetics and residue levels of carbendazim and epoxiconazole in citrus under field conditions were measured using dispersive solid-phase extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry. The citrus samples were extracted with acetonitrile and purified by primary secondary amine sorbent. The mean recoveries of carbendazim and epoxiconazole ranged from 86.2 to 105.6% and relative standard deviations were ≤9.8%. The half-lives of carbendazim and epoxiconazole in whole citrus ranged from 2.0 to 18.0 days. Hazard quotient (HQ) and risk quotient (RQ) models were applied to whole citrus for dietary exposure risk assessment based on the terminal residue test. Hazard quotients ranged from 0.066 to 0.134% and RQs from 18.48 to 82.12%. Carbendazim and epoxiconazole in citrus degraded rapidly following first-order kinetics models. The dietary risk of exposure to both carbendazim and epoxiconazole through citrus, based on HQ and RQ, was acceptable for human consumption. This study indicates scientifically validated maximum residue limits in citrus, which are currently lacking for epoxiconazole in China. © 2021 Society of Chemical Industry.

Investigation and human health risk assessment of multi-class veterinary antibiotics in honey from South Korea

Antibiotic residues in honey constitute potential threats to human health. To ensure food safety, a total of 26 antibiotics method based on liquid chromatography-tandem mass spectrometry for the determination of antibiotics was validated in honey. Sample preparation consists in acid hydrolysis and dispersive-solid phase extract clean-up methods. The primary secondary amine sorbent yielded the highest recoveries. All antibiotics showed good linearity, with correlation coefficients of more than 0.993. The method yielded limits of detection of 0.1–6.8 μg L−1, limits of quantification (LOQ) of 0.3–20.7 μg L−1, and recoveries of 70.5–107.4 %. The concentrations of individual antibiotics except chlortetracycline and tetracycline were below 100 ng mL−1. The chlortetracycline (38.2 %) and tetracycline (31.3 %) accounted for the highest antibiotic residues in honey samples. The estimation of exposure and risk assessment revealed that the upper residue levels of tetracycline-class exceeded the acceptable daily intake by 24.3–381.5 times. In particular, chlortetracycline alone accounted for 70 % of the hazard index, which was 4.62 in children and 2.26 in adults. This study calls attention to the human health risk of tetracyclines in honey consumption.

Validation of QuEChERS Method Coupled with LC-MS/MS for Determination of Thiamethoxam and its Metabolites in Wheat and Soil.

Thiamethoxam, a neonicotinoid insecticide, has been widely accepted for the control of sucking and certain chewing pests. Through different routes, i.e., wind drift, leaching, and surface runoff, it can reach non-target areas, which include humans as well. Therefore the fate of thiamethoxam in food grains and soil is of prime importance, entailing a need for pesticide use to be subject to steady observation. The review aimed to validate the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the detection of thiamethoxam and its metabolites in wheat leaves, grain, straw, and soil using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The QuEChERS method allows sample extraction by acetonitrile followed by cleanup with a primary secondary amine sorbent, magnesium sulphate, and graphitized carbon black. The method was validated in terms of selectivity, linearity, LOD, LOQ, matrix match, accuracy, and precision. The estimation of residues was done by LC-MS/MS. The recovery of thiamethoxam and its metabolites in wheat and soil samples was in the range of 81.22-98.14%. The LOQ for thiamethoxam and its metabolites was 0.01 mg/kg. The matrix effect values were in the acceptable range of -20 to +20%. The method allows a simple and fast extraction of thiamethoxam and its metabolites from wheat leaves, grain, straw, and soil. It could be helpful in the evaluation of regulatory and food safety decisions regarding the use of neonicotinoids. The method was validated according to the European Commission SANTE/12682/2019 guidelines. An accurate, simple, and sensitive analytical method was validated for thiamethoxam and its metabolites.

Micro Salting-Out Assisted Matrix Solid-Phase Dispersion: A Simple and Fast Sample Preparation Method for the Analysis of Bisphenol Contaminants in Bee Pollen.

In the present work, a novel sample preparation method, micro salting-out assisted matrix solid-phase dispersion (μ-SOA-MSPD), was developed for the determination of bisphenol A (BPA) and bisphenol B (BPB) contaminants in bee pollen. The proposed method was designed to combine two classical sample preparation methodologies, matrix solid-phase dispersion (MSPD) and homogenous liquid-liquid extraction (HLLE), to simplify and speed-up the preparation process. Parameters of μ-SOA-MSPD were systematically investigated, and results indicated the significant effect of salt and ACN-H2O extractant on the signal response of analytes. In addition, excellent clean-up ability in removing matrix components was observed when primary secondary amine (PSA) sorbent was introduced into the blending operation. The developed method was fully validated, and the limits of detection for BPA and BPB were 20 μg/kg and 30 μg/kg, respectively. Average recoveries and precisions were ranged from 83.03% to 94.64% and 1.76% to 5.45%, respectively. This is the first report on the analysis of bisphenol contaminants in bee pollen sample, and also on the combination of MSPD and HLLE. The present method might provide a new strategy for simple and fast sample preparation of solid and semi-solid samples.

Development of a QuEChERS-LCMS/MS method for simultaneous estimation of tebuconazole and chlormequat chloride in wheat crop

Tebuconazole (TBZ) and Chlormequat chloride (CCC) combination has been established as highly effective in reducing plant height of lodging prone wheat varieties. In this work, a novel analytical method employing the quick, easy, cheap, effective, rugged and safe (QuEChERS) cleanup technique and LC-MS/MS (liquid chromatography-tandem mass spectroscopy) was developed for simultaneous estimation of TBZ and CCC in wheat grains and harvest stage plant leaves. A total of 10 mL of acetonitrile and 50 mg of primary secondary amine (PSA) sorbent was consumed in the optimized QuEChERS process for leaves and grain samples. The LC-MS/MS analysis was performed using a C-18 column operating under electrospray ionization in positive mode. The QuEChERS approach achieved extraction recoveries in the acceptable range of 70%–120%, for both the compounds and was validated in terms of accuracy, precision, sensitivity and linearity. Persistence study was conducted using Lihocin (CCC 50% SL), Folicur (TBZ 25.9% EC) and their combination tank mix (Lihocin + Folicur-50% SL + 25.9% EC) applied as foliar spray twice in wheat crop (tester tall variety C-306). The results demonstrated that the developed QuEChERS-LCMS/MS is rapid and confirmatory for simultaneous quantification of both the test analytes in wheat crop.

Chemometrics Assisted QuEChERS Extraction Method for the Residual Analysis of Organophosphate Insecticides: Application to Their Dissipation Kinetics in Open Field Ecosystem

The present study aimed to investigate the dissipation kinetics and residual levels of five organophosphate pesticides in a carrot- and potato-field ecosystem by sensitive and selective liquid chromatography-tandem mass spectrometry method. The optimization of the modified QuEChERS extraction method was carried out using the cost-effective chemometric tool equipped with Plackett-Burman and central composite designs. Based on the response surface methodology the optimized conditions were found to be 56.5 mg of primary secondary amine sorbent, 1.53 g of sodium chloride, and 213 mg of C18. The average recoveries of the method were obtained over the range of 81.6 to 96.0 % with a relative standard deviation < 14.7 %. The detection and quantification limit ranged from 0.7 to 1.0 μg/kg and 1.0 to 5.0 μg/kg, respectively. The data showed that the first-order model was the best fit for the dissipation of five organophosphate pesticides with a regression coefficient of more than 0.99. The half-lives for all the studied pesticides were below 6.6 and 5.1 days for carrot and potato, respectively. The harvesting intervals for pesticides on the carrot and potato fields were within 28 and 21 days, respectively. The study results contribute to establishing the scientific basis of the dosage for organophosphate pesticide use in the vegetable field.

Development and Application of a Multi-Residue Method to Determine Pesticides in Agricultural Water Using QuEChERS Extraction and LC-MS/MS Analysis

Agricultural water is closely linked to surface and ground water as well as soil; hence, ensuring its safety is an important endeavor. We used the “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) method to analyze multi-residue pesticides in agricultural water by using a combined-sorbent-based clean-up procedure. Among the various sorbents examined, clean-up using ENVI-Carb combined with a primary secondary amine sorbent delivered the highest recovery of multi-residue pesticides (&gt;93.9%). While the developed method showed satisfactory linearity (R2 &gt; 0.9991), precision, and specificity, recovery was low for pyrazolate (29.1%) and thidiazuron (59.2%). The limits of detection and quantification for the 55 pesticides targeted in this study were in 0.02–3.0 μg L−1 and 0.1–9.9 μg L−1, respectively. The developed method was used to identify and quantify multi-residue pesticides during sample analysis. The results suggest that the QuEChERS method employing a combination of ENVI-Carb and another sorbent can be applied for the effective analysis of multi-residue pesticides in agricultural water.

Development and validation of a multiresidue method for pesticides and selected veterinary drugs in animal feed using liquid- and gas chromatography with tandem mass spectrometry.

Animal feeds are often reported to be contaminated with chemical residues, and when present above the maximum legal limit, these compounds can cause harmful effects to consumers of animal produce. Thus, animal feed safety is an important regulatory concern. The aim of this study was to optimise a multiresidue method for the simultaneous analysis of multi-class pesticides and a number of frequently used veterinary drugs using LC-MS/MS and GC-MS/MS. The method was validated in a range of feed matrices, including maize feed, poultry feed and mixed feed concentrate. The optimised sample preparation workflow involved extraction of feeds (5g) with ethyl acetate (10mL), followed by a freezing step (at -20°C) used for eliminating the matrix co-extractives. The extract was further cleaned by dispersive solid phase extraction with a combination of primary secondary amine, C18 and florisil sorbents. From the cleaned-extract, an aliquot was analysed by GC-MS/MS, while another portion of it was solvent-exchanged to acetonitrile:water (50:50) and then analysed by LC-MS/MS. This method effectively minimised the matrix interferences. A total of 192 pesticides was analysed by GC-MS/MS within a runtime of 22min. The LC-MS/MS method was validated for 187 compounds including 17 veterinary drugs. For most of the compounds, the limit of quantification (LOQ) was 0.01mg/kg. The recoveries at LOQ and higher levels ranged between 70% and 120%, with precision-RSDs of < 20%. The method provided a precise analysis in a wide range of market-feed samples. As shown, the method is suitable for regulatory and commercial testing purposes.

Combination of dispersive solid phase extraction with solidification organic drop-dispersive liquid-liquid microextraction based on deep eutectic solvent for extraction of organophosphorous pesticides from edible oil samples.

A dispersive solid phase extraction method was combined with deep eutectic solvent-based solidification of floating organic drop-dispersive liquid-liquid microextraction and used for the extraction/preconcentration of some organophosphorus pesticides residues from edible oil samples. The extracted analytes were quantified with gas chromatography-nitrogen phosphorous detector. In this procedure, the sample lipids are saponified with a sodium hydroxide solution and then the analytes are adsorbed onto a primary secondary amine sorbent. After that the analytes are desorbed with acetone as an elution/dispersive solvent and mixed with choline chloride: 3,3-dimethyl butyric acid deep eutectic solvent and the mixture is rapidly dispersed into deionized water. Then, the obtained cloudy solution is centrifuged and placed into an ice bath. The extraction solvent is solidified on the top of the solution. Finally, it is removed and dissolved in acetonitrile, and 1 µL of the solution is injected into the separation system. Validation of the method showed that limits of detection and quantification were in the ranges of 0.06-0.24 and 0.20-0.56 ng mL-1, respectively. Enrichment factors and extraction recoveries of the analytes ranged from 170-192 and 68-77%, respectively. The method had an acceptable precision with relative standard deviations less than ≤9.2% for intra- (n=6) and inter-day (n=6) precisions at four concentrations (3, 10, 50, and 250 ng mL-1, each analyte). Finally the method was used for determination of the analytes in five edible oil samples.

Multi-residue Analysis of Pesticides in Turmeric (Powder and Rhizome) Using Gas Chromatography Tandem Mass Spectrometry.

Turmeric is widely used as an ingredient of food and medicinal products. There exists no validated method for multi-residue analysis of pesticides in turmeric. This study was undertaken to develop a simple and robust method for the quantitative determination of multi-class pesticides in turmeric powder and rhizome by GC-MS/MS. Initially, the samples were soaked in water for 30 min and homogenized to a fine paste. A portion of this paste (2 g) was extracted with acetonitrile (2 mL) and partitioned with hexane (2 mL) after adding 5 mL of 20% NaCl. The cleanup step involved dispersive solid phase extraction with graphitized carbon black (GCB, 5 mg/mL). Its performance was evaluated against primary secondary amine (PSA) and C18 sorbents. The cleaned extract was evaporated to dryness and reconstituted in ethyl acetate before GC-MS/MS analysis. The method was validated for a mixture of 208 multi-class pesticides at 10 ng/g and higher levels (i.e., 20 and 50 ng/g). The findings, which demonstrated a satisfactory recovery and precision (RSDs <20%) for all compounds at 10 ng/g and higher spiking levels, are aligned with the analytical quality control criteria of SANTE/12682/2019 guidelines. The cleanup effect of GCB was much superior to that of PSA, C18, and their combinations. The solvent exchange step with hexane was effective in removing co-extractives and minimizing matrix effects. This method complies with the regulatory requirements and is fit-for-purpose for pesticide residue monitoring in turmeric. The study reports a validated GC-MS/MS method for multi-residue analysis of pesticides in turmeric for the first time. The method provided a high throughput analysis of multi-class pesticides in turmeric rhizome and powder matrices with satisfactory selectivity, sensitivity, accuracy, and precision.