Monitoring of Pesticide Contamnation of Selected Legume Crops Imported in UAE

Food contamination with pesticide residues is a serious concern. In United Arab Emirates, ministry of climate change and environment (MOCCAE) carries out incidence/level monitoring in order to acquire data on the presence and amounts of pesticide residues in particular commodity/chemical combinations. This monitoring aimed to provide the necessary information on quantitative and qualitative pesticide multiresidues in imported legume crops. Sampling plan of 2375 selected legume imported into the UAE has been examined as part of an official surveillance program, these samples include beans, peas, peanuts, lupine and lentils, they were collected from across United Arab Emirates (UAE) ports of entry during 2020 and 2021 by certified staff. These samples were analyzed by modified QuEChERS method for pesticide residue screening based on multi-reaction monitoring (MRM) mode with gas and/or liquid chromatography tandem mass spectrometry for monitoring more than 400 pesticides residues in these legume crops. The method used in this study was validated following the European Commission guidelines achieving good recovery values in the range 70–120% with relative standard deviation values lower than 20% and providing limits of quantification of the method in the low mg/kg range, in accordance with the maximum residue limits set by European policies and CODEX. The results showed that the majority (98.8%) of legume crops samples analyzed had compliance with the legislation in force in UAE and 29 samples (1.2%) contained residues above MRLs established by the Codex Committee on pesticide residues as well as by the European Union. This monitoring is a part of a surveillance study for pesticide control in food samples. Based on the results current monitoring program provide a valuable source of information for estimating dietary exposure of UAE consumers to pesticide residues, and to check compliance with the national maximum residue levels in legume samples.

Avaliação de resíduos de agrotóxicos em amostras de farinha de trigo por espectrometria de massas / Evaluation of pesticide residues in wheat flour by mass spectrometry

Os cereais são uma importante fonte alimentícia e econômica, dentre eles se destaca o trigo e sua farinha. Durante o cultivo, visando o controle de pragas, frequentemente são utilizados os agrotóxicos, porém seu uso abusivo pode acarretar danos à saúde humana e ao meio ambiente. O trabalho teve como objetivo avaliar a presença de resíduos de agrotóxicos em amostras de farinha de trigo comercializadas no estado de São Paulo, utilizando o método QuEChERS (Rápido, Fácil, Barato, Efetivo, Robusto e Seguro) modificado, seguido de análise por CG-EM/EM e CLUE-EMAR para identificação e quantificação. No total, 124 ingredientes ativos (i.a.) estavam dentro dos critérios de aceitação para linearidade, limites de detecção e quantificação, exatidão e precisão (intervalo de confiança de 95%; k = 2). Os resultados de 25 amostras indicaram a presença de bifentrina, fenitrotiona, clorpirifós, deltametrina, lambda-cialotrina e pirimifós-metílico em farinha de trigo comum e os quatro últimos i.a. também foram detectados em farinha de trigo orgânica. O pirimifósmetílico foi detectado em 92% das amostras. Os i.a. encontrados nas amostras estavam abaixo do Limite Máximo de Resíduos (LMR) estabelecidos pela Agência Nacional de Vigilância Sanitária (Anvisa) para farinha de trigo e as amostras foram consideradas próprias para o consumo (AU).

Cereals are an important economic factor and food source, which wheat and its flour stand out. Pesticides are often employed to control harmful organisms, but their abusive use can cause damage to human health and the environment. This study aimed to evaluate the presence of pesticide residues in wheat flour samples commercialized in the state of São Paulo ­ Brazil, using the modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method, followed by GC-MS/MS and UHPLC-HRMS analysis for identification and quantification. Thus, 124 active ingredients (a.i.) were within acceptable criteria for linearity, limits of detection and quantification, accuracy (trueness), and precision (95% confidence level; k = 2). The results for 25 wheat flour samples showed the presence of bifenthrin, fenitrothion, chlorpyrifos, deltamethrin, lambda-cyhalothrin, and pirimiphos-methyl, and the last four a.i. were also detected in organic wheat flour. Pirimiphos-methyl was detected in 92% of all samples. All compounds were found below the Maximum Residue Levels (MRL) established by Brazilian Health Regulatory Agency (Anvisa) for wheat flour and the samples were considered suitable for consumption (AU).

Determination of Three Types of New Psychoactive Tryptamines in Blood by QuEChERS Combined with UPLC-MS/MS / 法医学杂志

Objective To establish a method combining QuEChERS and ultra-high liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） for rapid screening and testing of three types of new psychoactive tryptamines in human blood： 5-MeO-DALT, 5-MeO-MiPT and 5-MeO-DiPT. Methods The effects of the type of extractant, the type and dosage of salting-out agent, and the dosage of adsorbent on the test results of the three tryptamines were investigated. Blood samples were processed by QuEChERS method and then determined by UPLC-MS/MS. Results The linear relationships of 5-MeO-DALT, 5-MeO-MiPT and 5-MeO-DiPT in human blood were good in the range of 0.5-100, 0.5-100 and 0.2-100 ng/mL, respectively, with their coefficients higher than 0.99. The limits of detection （LODs） were 0.1-0.2 ng/mg. The recoveries ranged from 84.86% to 94.57%. Intra-day and inter-day precisions were good. Conclusion The method is simple, rapid, easy to operate and has a high recovery. It is suitable for the qualitative and quantitative study of tryptamines in blood and can provide the reference for public security organs to deal with related cases.

Simultaneous determination of 13 hormones in Testis et Penis Cervi using QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry / 中国中药杂志

A reliable QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) analysis method was developed for the simultaneous determination of 13 steroid hormones(nrolone, androstenedione, methyltestosterone, testosterone, norethindrone, medroxyprogesterone, progesterone, diethylstilbestrol, hexan-stilbestrol, estradiol, estrotriol, cortisone, hydrocortisone) in Testis et Penis Cervi. The samples were extracted with methanol and purified by QuEChERS. Subsequently, the samples were separated by ACQUITY BEH C_(18) column and detected in the multiple reaction monitoring(MRM) mode under electrospray ionization in the positive and negative ion modes, respectively. Significant differences in the content of thirteen steroid hormones in Testis et Penis Cervi between the sika deer at different periods and the red deer were observed. The content of testosterone(10.88 μg·kg~(-1)) and hydrocortisone(12.82 μg·kg~(-1)) in Testis et Penis Cervi derived from rutting sika deer was significantly higher than the content of testosterone(1.05 μg·kg~(-1)) and hydrocortisone(0.73 μg·kg~(-1)) from antler growth stage. The content of progesterone in Testis et Penis Cervi derived from red deer was 6.07 μg·kg~(-1), significantly higher than that from sika deer. The content of progesterone in the testicle of red deer reached 27.46 μg·kg~(-1), 4.5 times greater than that in the penis of red deer. The sensitivity, accuracy, and precision of the method can meet the detection requirements, and the developed method is suitable for the measurement of hormones in animal-derived food.

Current status of organophosphorus pesticide residues in root and rhizome medicinal materials and research progress of rapid detection methods / 中国中药杂志

The medicinal plants with roots and rhizomes as the medicinal parts account for about 1/3 of Chinese medicinal herbs. Root and rhizome medicinal materials are widely used in clinical practice, whereas their wild resource reserves are insufficient to meet the market demand. With the expansion of planting areas, the formation of large-scale production areas, and the increase in planting years, diseases and insect pests of these medicinal plants, which are diverse and have broad transmission routes, strong concealment, and heavy damage, have become more and more serious. The prevention and control of these diseases and insect pests is characterized by multiple ways of pesticide application, large consumption of pesticides, susceptibility to soil barrier, difficulty in the control, and unstable control efficiency. Organophosphorus pesticides(OPPs) are widely used in the cultivation of Chinese medicinal plants because of their diverse varieties, broad-spectrum, good efficacy, and low residues, and have a positive effect on the yield and quality of Chinese medicinal materials. However, the abuse of OPPs not only increases the planting cost, but also affects the quality and safety of Chinese medicinal plants, the safety of clinical use of Chinese medicine, and the ecological safety of production areas. This paper reviewed the research and development progress of OPPs, the registration status of OPPs used in root and rhizome medicinal materials, residue limit standards, residue status, and rapid detection technology progress of OPPs. This review aims to provide research ideas and references for standardizing the use of OPPs in root and rhizome medicinal materials, reducing OPP residues, and establishing a fast, efficient, accurate, and reliable method for the detection of OPP residues in Chinese herbal medicine.

Qualitative screening of 169 veterinary drug residues in bearbile powder by QuEChERS-ultra high performance liquid chromatography-tandem mass spectrometry / 药学学报

A QuEChERS-ultra high performance liquid chromatography-tandem mass spectrometry method was developed for qualitative screening of 169 veterinary drug residues in bear bile powder, including β-agonists and inhibitors, antibiotics (penicillins, β-lactams, sulfomamides, quinolones, chloramphenicals, tetracyclines, nitroimidazoles, macrolides, polyethers, etc.), antiviral drugs, anthelminitics, steroid hormones, nonsteroidal antiinflammatory drugs (NSAIDs) and sedatives. The samples were extracted by Na2EDTA-McIlvaine buffer solution and 5% fomic acid-acetonitrile solution, then purified by dispersive solid phase extraction. Detection of veterinary drug residues by ultra high performance liquid chromatography-triple quadrupole mass spectrometry was conducted and qualitative confirmed by ion ratios. The limits of detection of 169 veterinary drugs were 1-1 000 μg·kg-1. The method is simple and fast, which had been used for the analysis of actual samples, and can be extended to the detection of similar matrix.

Determination of 53 pesticide residues in different category of Fritillaria by QuEChERS and GC-MS/MS / 中草药

Objective: To establish a method for simultaneous determination of 53 kinds of pesticides residual in different category of Fritillaria by using QuEChERS and gas chromatography tandem mass spectrometry, and applying to 193 batches sample screening. Methods: The forbidden, restricted and commonly used pesticides were selected as detecting indexes according to the result of this investigation. The samples were prepared by QuEChERS, and quantitative analysis was carried out by GC-MS/MS multiple-reaction monitoring (MRM) model. There were three supplemental levels for determining recoveries and RSD. Results: The results showed that all the 53 pesticides had good linearity in certain ranges with the correlation coefficients (R) higher than 0.997 8. The recoveries of more than 86.8% pesticides were ranged from 60% to 140% at three supplemental levels (1×LOD, 2×LOD, and 10×LOD), with the RSDs less than 15%. The LOD ranged of all pesticides were below 0.01 mg/kg. The result of 193 batches sample screening showed that 91 batches sample were detected 14 pesticides, and the detection rate was 47.2%. Conclusion: The detecting indexes is meaningful and the developed method is simple, rapid, sensitive, and reliable for screening multiple pesticide residues in different category of Fritillaria. The result has certain reference value for the cultivation and circulation supervision of different category of Fritillaria.

Analysis of pesticide residues in commercially available chenpi using a modified QuEChERS method and GC-MS/MS determination / 药物分析学报

To ensure the safety of the commercially available chenpi, a convenient and fast analytical method was developed for the determination of 133 pesticide residues in chenpi using gas chromatography-tandem mass spectrometry (GC-MS/MS). In this study, different extraction solvents, redissolution solvents and adsorbents were tested according to the recovery and purification effect to obtain a modified QuEChERS method. The samples were extracted with acetonitrile. During the clean-up step, octadecyl-modified silica (C18) and graphitized carbon black (GCB) were selected, and aminopropyl (NH2) was used instead of primary secondary amine (PSA) because of its weaker ion exchange capacity which had little effect on the recovery of ditalimfos. Samples were quantified by matrix-matched calibration with internal stan-dards. All pesticides showed good linearity in the respective range, both with values of r2 >0.99. The average recoveries of the pesticides spiked samples ranged from 70.0％ to 112.2％ with the RSDs of 0.2％–14.4％. The modified QuEChERS method was validated and applied to twenty real samples. Five pesticides were found in eight batches, but no pesticide exceeded the maximum residue limits (MRL, MRL reference to European commission).

Simultaneous determination of 15 mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution / 上海预防医学

Objective To develop a method for the simultaneous determination of 15mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution. Methods The samples were extracted by 2% formic acid acetonitrile-water (50 : 50, V/V) and then purified with QuEChERS EMR-Lipid approach.The mycotoxins were fully separated on a pentafluorophenyl column under a gradient elution with methonal-0.01%formic acid aqueous solution.The mycotoxins were analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode and quantified by isotope internal standard method. Results Fifteen mycotoxins had good linear relationship in the certain correlation ranges with the correlation coefficients all above 0.995 and the detection limits were 0.1－10 μg/kg.The mean recoveries ranged from 81.2% to 115.3% with RSD (n=6) varying from 2.1% to 10.7%. Conclusion The method is simple, highly sensitive, practical, and proves to be suitable for quantitative analysis of 15 mycotoxins in peanuts.

Método cualitativo rápido ( screening ) para ladetección de residuos de plaguicidas en frutas y hortalizas / Qualitative screening method for pesticide residues detection in fruits and vegetables / Método qualitativo rápido (screening) para a detecção de resíduos de pesticidas nas frutas e nos vegetais

Resumen Debido a la importancia de desarrollar metodologías que permitan el análisis de los residuos agrícolas, el presente trabajo validó un método cualitativo rápido (screening) para el análisis de residuos de plaguicidas en frutas y hortalizas. La metodología se basó en el método de extracción QuEChERS, versión europea, con un paso adicional de limpieza por cromatografía de permeación por gel (GPC), lo cual permitió reducir la cantidad de componentes de la matriz en el extracto final. El análisis fue realizado por cromatografía de gases/espectrometría de masas con un analizador cuadrupolo simple. La metodología resultó adecuada para el análisis cualitativo de 31 plaguicidas a su respectivo límite máximo de residuos. Los resultados en muestras reales fueron consistentes respecto a una metodología cuantitativa de rutina, por ende, la metodología resultó ser una buena alternativa para el análisis rápido de estos contaminantes.

Abstract Because of the importance of developing methodologies that allow agricultural residues analysis, a rapid screening qualitative method for the determination of pesticides residues in fruits and vegetables was validated. The methodology was based on the European QuEChERS extraction method with an additional cleaning step by gel permeation chromatography (GPC), which helped to reduce the number of matrix components in the final extract. The analysis was carried out by gas chromatography coupled to mass spectrometry with a single quadrupole analyzer. The methodology was appropriate for the qualitative analysis of 31 pesticides at their respective maximum residue limits. Consistent results were obtained with respect to a quantitative routine methodology in the analysis of real samples, hence the methodology was proven to be a good alternative for the fast analysis of these contaminants in fruits and vegetables.

Resumo Devido à importância de desenvolver metodologias que permitam analisar os resíduos agrícolas, o presente trabalho validou de um método qualitativo rápido (screening) para a análise de resíduos de pesticidas nas frutas e vegetais. A metodologia foi baseada no método de extração QuEChERS versão Europeia com um passo adicional de limpeza por meio de cromatografia de permeação em gel (GPC), o que permitiu reduzir a quantidade de componentes de matriz no extrato final. A análise foi realizada por cromatografia gasosa/espectrometria de massa com um analisador de quadrupolo simples. A metodologia foi adequada para a análise qualitativa de 31 pesticidas aos seus respectivos limites máximos de resíduos. Os resultados obtidos em amostras reais foram consistentes com uma metodologia quantitativa de rotina, portanto, a metodologia estudada tem demonstrado ser uma boa alternativa para a análise rápida destes contaminantes em frutas e vegetais.

LC-MS/MS analysis of neonicotinoid insecticides: Residue findings in chilean honeys / LC-MS/MS análises de inseticidas neonicotinoides: Resíduos encontrados em méis chilenos

ABSTRACT Neonicotinoids are a relatively new generation of insecticides that have been used for control of pests such as aphids, leafhoppers and whiteflies. This paper presents for the first time a determination of residues of four neonicotinoid insecticides (acetamiprid, thiamethoxam, thiacloprid and imidacloprid) in Chilean honey using QuEChERS extraction and UHPLC-MS/MS analysis. The limits of detection and quantification found for all analytes ranging from 0.34 to 1.43 μg kg-1 and from 0.30 to 4.76 μg kg-1, respectively. The extraction using QuEChERS method provided recoveries over 79% and the precision showed coefficient of variation lower than 20%. These data are in agreement with the international criteria that recommend general recovery limits of 70 - 120%. Of the 16 samples analyzed, in three honey samples neonicotinoids pesticides were detected. These three samples were collected from the same geographical area (Rengo). Fruit and grain production characterize the province of Rengo. The analysis of the botanical origin of these honeys showed the absence of pollen grains of crops and the majority presence of pollen grains of weeds such as Medicago sativa, Galega officinalis and Brassica rapa, which could be associated with crops. Although the residue levels found were low, the results also confirm the actual occurrence of a transfer of neonicotinoid insecticides from exposed honeybees into honey.

RESUMO Os neonicotinóides são uma geração relativamente nova de inseticidas que tem sido utilizado para o controle de pragas, como pulgões, cigarrinhas e moscas brancas. Este artigo apresenta pela primeira vez a determinação de resíduos de quatro inseticidas neonicotinóides (acetamiprida, tiametoxam, tiaclopride e imidaclopride) em méis chilenos empregando para extração o método QuEChERS seguido de UHPLC-MS/MS. Foram encontrados limites de detecção e quantificação aceitáveis para todos os analitos variando de 0,34 a 1,43 μg kg-1 e de 0,30 a 4,76 μg kg-1, respectivamente. A extração usando o método QuEChERS proporcionou uma recuperação maior que 79% e a precisão do método não excedeu um coeficiente de variação de 20%. Esses dados estão de acordo com os critérios internacionais que recomendam limites gerais de recuperação de 70 - 120%. Das 16 amostras de mel analisadas foram detectados pesticidas neonicotinoides em três delas. Essas três amostras foram coletadas na mesma área geográfica (Rengo), a qual se caracteriza pela produção de grãos e frutas. A análise da origem botânica desses méis mostrou a ausência de grãos de pólen de espécies cultivadas nesta zona, porém mostrou uma presença majoritária de grãos de pólen de ervas daninhas, como Medicago sativa, Galega officinalis e Brassica rapa, as quais podem estar associadas a estes cultivos. Embora os níveis de resíduos neonicotinoides encontrados neste estudo são baixos, os resultados confirmam a ocorrência atual de uma transferência destes inseticidas ao mel das de abelhas expostas.

Simultaneous determination of 21 organophosphrous pesticides in human serum by QuEChERS-gas chromatography-mass spectrometry / 中华劳动卫生职业病杂志

Objective@#A method for the simultaneous determination of organophosphrous pesticides inhuman serum was developed.@*Methods@#Using C18 and PSA as absorbent, 21 organophosphrous pesticides including methamidophos, dichlorvos, acephate, Omethoate, demeton and etc. in human serum were determined by combing QuEChERS with GC-MS, organophosphrous pesticides were qualitatedsimultaneously by retention time and characteristic ions. Their contents were determined by internal standard method of quantitative ions.@*Results@#The linear range was from0to 0.60μg/ml with a good correlation coefficients (r ≥ 0.9961) . The LODs of this methodranged from 0.0009 to 0.0111 μg/ml. The average recoveries of3 organophosphrous pesticides (methamidophos、dichlorvos and acephate) ranged from 71.8%~85.3%, The average recoveries of other 18 organophosphrous pesticidesranged from 82.9%~102.9%. The relative standard deviations were0.8%~7.0%.@*Conclusion@#The convenient operation and versatility of this method are suitable forthe fast screening and accurate detection of 21 organophosphrous pesticides in human serum.

Development and application of a simultaneous quantitative analysis method of 58 pesticide residues in Anemarrhena asphodeloides based on QuEChERS- GC-QQQ-MS/MS / 中草药

Objective: To establish a simultaneous quantitative analysis method of 58 pesticide residues in Anemarrhena asphodeloides based on QuEChERS-GC-QQQ-MS/MS technique. Methods: This study was performed on a Shimadzu GC-QQQ-MS/MS spectrometer, equipped with a SHIMADZU SH-Rxi-5Sil MS column (30 m × 0.25 mm, 0.25 μm). The temperature of injection port was 250 ℃, the injection volume was 1.0 μL, the injection mode was splitless, the injection pressure was 250 kPa; The carrier gas was high purity helium and the carrier gas control mode was constant linear velocity mode; The column flow rate was 1.69 mL/min, the line speed was 47.2 cm/s, the purge flow rate was 5 mL/min. The temperature rise method was the gradient program: The initial temperature was 50 ℃, hold the state for 1 min, first raise the temperature to 125 ℃ with 25 ℃/min, then raise the temperature to 300 ℃ with 10 ℃/min, keep the state for 15 min; The balance time was 0.5 min. The QuEChERS method was used to purify the test sample solutions, and the calibration was carried out using the standard curve of blank matrix matching, using a stable isotope internal standard for quantitative. Results: Quantitative determination of 58 pesticide residues in 30 batches of A. asphodeloides samples was carried out. The results showed that there were five batches of samples detecting a small amount of p,p’-DDE, three batches of samples were detected trifluralin, two batches of samples were detected chlorpyrifos, and one batch of samples were detected butralin. Conclusion: The development and validation quantitative analysis method of 58 pesticide residues based on QuEChERS-GC-QQQ-MS/MS has good applicability, which is of reference value for the establishment of other pesticide residues in herbs.

Multi-Residue Analysis of Pesticides in Radix Ophiopogonis by GC-MS/MS / 中国药学杂志

OBJECTIVE: To establish a method for simultaneous determination of 56 kinds of pesticide residues in Radix Ophiopogonis by using gas chromatography tandem mass spectrometry (GC-MS /MS), and apply it to screening of 137 batches of samples. METHODS: The forbidden, restricted and frequently-used pesticides were selected as the detecting indexes. The samples were prepared by QuEChERS, and quantitative analysis was carried out by GC-MS /MS in multiple-reaction monitoring (MRM) mode. There were three supplemental levels for detection recoveries and RSD. RESULTS: All the 56 pesticides had good linearity in certain ranges with correlation coefficients(r) higher than 0.997 8. The recoveries of 96.4% pesticides ranged from 60% to 130% at three supplemental levels (1, 2 and 10 LODs), with the RSDs of 92.9% pesticides less than 15%. The LODs for most of the selected pesticides were below 0.01 mg•kg-1. Twelve pesticides were detected in 137 batches of samples. CONCLUSION: The detecting indexes are meaningful and the developed method is simple, rapid, sensitive and reliable for screening multiple pesticide residues in Radix Ophiopogonis. The test result has certain reference value for the cultivation and distribution supervision of Radix Ophiopogonis.

Incidence of aflatoxin M1 in fresh milk from small farms

Abstract The objective of this work was to determine aflatoxin M1 in fresh milk from fifty-two small farms in the city of Concórdia - SC, Brazil. Samples from the cooling tanks of each property were collected from November 2014 to January 2015. The QuEChERS method was used for the extraction of aflatoxin M1, and quantification was performed in UHPLC-FL. 40.4% of the analyzed samples (eg, 21 samples) showed contamination levels by aflatoxin M1 above the maximum limit allowed by the Brazilian regulation, which is 0.5 μg L-1. These results suggest the importance of implementing Good Practices in obtaining feed for dairy cows, since the contamination of milk by aflatoxin M1 occurs through the biotransformation of aflatoxin B1, after the ingestion of feed or silage contaminated by the animals, posing risk to the animals themselves, as well as to consumers of milk and dairy products.

Desarrollo y validación de un método multiresiduo para el análisis de plaguicidas en miel por UFLC-MS / Development and validation of a multiresidue method for pesticide analysis in honey by UFLC-MS / Desenvolvimento e validação de um método de resíduos múltiplos para o analise de agrotóxicos em mel por UFLC-MS

Resumen Se desarrolló un método para la determinación de residuos de plaguicidas en miel de abejas mediante cromatografía líquida ultra rápida acoplada a espectrometría de masas(cuádruplo sencillo). Se partió del método QuEChERS, evaluando las siguientes variables: (i) cantidad de muestra, (ii) tipo de sal para el control de pH, (iii) valor de pH del buffer y (iv) mezclas de limpieza. Adicionalmente y con el propósito de demostrar la confiabilidad del método, se evaluaron diferentes parámetros como exactitud, límites de detección y cuantificación, linealidad y selectividad. Los resultados mostraron que, mediante las modificaciones realizadas, se logró obtener un método más selectivo y se mejoró la exactitud de 19 plaguicidas respecto al método QuEChERS original. Por otro lado, mediante el proceso de validación, se encontró que el método es apto para el análisis de 50 plaguicidas (de 56 que se emplearon). Se obtuvieron porcentajes de recuperación entre el 70 y 120% y coeficientes de variación inferiores al 15%

Abstract A method for the determination of pesticide residues in honey by ultra fast liquid chromatography coupled with mass spectrometry was developed. For this purpose, different variations of the QuECHERS method were performed: (i) amount of sample, (ii) type of salt to control pH, (iii) buffer pH, and (iv) different mixtures for cleaning-up. In addition, to demonstrate that the method is reliable, different validation parameters were studied: accuracy, limits of detection and quantification, linearity, and selectivity. The results showed that by means of the changes introduced it was possible to get a more selective method that improves the accuracy of about 19 pesticides selected from the original method. It was found that the method is suitable for the analysis of 50 pesticides, out of 56. Furthermore, with the developed method recoveries between 70 and 120% and relative standard deviation below 15% were found.

Resumo Foi desenvolvido um método para a determinação de resíduos de pesticidas no mel por cromatografia líquida ultrarrápida acoplada à espectrometría de massa. Para este efeito, foram realizadas diferentes variações do método QuEChERS: (i) quantidade de amostra, (ii) tipo de sal para o controle do pH, (iii) valor do pH do tampão, (iv) diferentes misturas de limpeza. Além disso, a fim de demonstrar que o método é confiável, diferentes parâmetros foram validados como: precisão, limite de detecção e quantificação, linearidade e seletividade. Os resultados mostraram que, por meio das modificações é possível obter um método mais seletivo que melhora a precisão de cerca de 19 pesticidas selecionados, respeito ao método original. Adicionalmente, foi determinado que a validação do método estabeleceu que este é adequado para a análise de 50 pesticidas (56 foram utilizados). Foram obtidos percentagens de recuperação entre 70 e 120% e coeficientes de variação menores ao 15%.

High Throughput Screening of 86 Kinds of Glucocorticoids in Cosmetics Using QuEChERS and Isotope Dilution-Liquid Chromatography Copuled to High Resolution Time-of-Flight Mass Spectrometry / 分析化学

A high throughput screening method based on QuEChERS purification and stable isotope dilution-liquid chromatography coupled to high resolution time-of-flight mass spectrometry was developed for the simultaneous rapid determination of 86 kinds of glucocorticoids (GCs) in cosmetics.The analytes were extracted by acetonitrile, and then the extracts were purified using an improved QuEChERS method.The chromatographic separation was performed on a novel multiple chromatographic retention mechanisms column of Poroshell 120 PFP (100 mm × 2.1 mm, 2.7 μm) with gradient elution using 0.2% (V/V) acetic acid and acetonitrile as mobile phase.The accurate mass database of parent ions and mass spectra library of fragment ions of 86 GCs were established under positive ionization mode with electrospray ionization source.Based on the method described above, the qualitative identifications of the 86 GCs were accomplished without the contrast of standard substances.The results demonstrated that the linear range of this method was from 2 μg/L to 200 μg/L with good correlation coefficients of R2>0.99.The average recoveries of the 86 GCs ranged from 66.2% to 112.8%, and the relative standard deviation (RSDs) was 4.6%-13.9% at three different spiked levels.The limit of detection (LOD) and quantification (LOQ) were 0.006-0.015 mg/kg and 0.02-0.05 mg/kg, respectively.The method is simple, efficient, reliable and accurate, and is suitable for high throughput screening of 86 GCs added illegally in cosmetics.

Determination of 38 Kinds of Pesticide Residues in Nuts by QuEChERS-Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry / 分析化学

A multi-residue analysis method was developed for the determination of 38 kinds of pesticides in nuts (almonds, peanuts, cashew nuts and walnuts) by QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry.The pesticide residues were extracted with acetonitrile.The extract was cleaned up with PSA, C18 and Oasis PRiME HLB, and then analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode.External standard method was employed to quantify.The limits of detection (LODs, S/N=3) of this method were between 0.01 and 10 μg/kg, and the limits of quantitation (LOQs, S/N=10) were between 0.05-20 μg/kg.All of the tested pesticides showed good linear relationship (r>0.991).The practical samples were determined at three spiked levels and the average recoveries were between 51.0% and 126.0%.The RSDs were less than 20%.This method was simple, sensitive and accurate, and could be used for the routine analysis of pesticide residues in nuts.

Determination of Ephedrine Hydrochloride in Tongxuan Lifei Pills by Accelerated Solvent Extraction Com-bined with QuEChERS Purification / 中国药师

Objective:To study the feasibility of the determination of ephedrine hydrochloride in Tongxuan Lifei pills by acceler-ated solvent extraction ( ASE) combined with QuEChERS purification, and compare the results with those of the extraction method in Chinese Pharmacopoeia. Methods: The extraction efficiency of ephedrine hydrochloride in Tongxuan Lifei pills determined by HPLC was used as the evaluation index, and the operation parameters of ASE were optimized by orthogonal experiments. Results: The opti-mum conditions of ASE for the determination of ephedrine hydrochloride in Tongxuan Lifei pills were as follows:the samples were defat-ted by n-hexane ( the extraction temperature was 80℃, the static extraction time was 5 min for one cycle, and the flush volume was 100%. ) ,and then methanol was used as the extraction solvent for the extraction of ephedrine hydrochloride ( the extraction temperature was 80℃,the static extraction time was 8 min for three cycles) ,in the end, the impurities were purified by PSA purifying agent. Using the optimized ASE method to extract ephedrine hydrochloride in Tongxuan Lifei pills, the extraction time was reduced to 40 minutes with less interference, and compared with that of the method in Chinese Pharmacopoeia, the determination of the relative standard devi-ation was less than 5%. Conclusion:The ASE technique combined with QuEChERS purification is simple, quick and effective,and it can be used as the pretreatment method for the determination of ephedrine hydrochloride in Tongxuan Lifei pills.

Simultaneous determination of sixteen mycotoxins contaminants in cogon rootstalk by QuEChERS-UPLC-QqQ mass spectrometry / 中国中药杂志

A method for the simultaneous determination of sixteen mycotoxins in cogon rootstalk was developed using ultra-performance liquid chromatography coupled with triple quadropole mass spectrometry(UPLC-QqQ-MS/MS). The samples were extracted with acetonitrile contained 1% acetic acid and purified by QuEChERS method. The separation was performed on an Agilent Eclipse Plus C₁₈column by gradient elution using methanol and 0.01% aqueous formic acid as mobile phase. The targeted compounds were detected in MRM mode by mass spectrometry with electrospray ionization(ESI)source operated in positive ionization mode. The linear relationships of the sixteen mycotoxins were good in their respective linear ranges. The correlation coefficients(r)ranged among 0.996 2-1.000. The LOQs of the sixteen mycotoxins were between 0.03 and 186.68 μg•kg ⁻¹. The average recoveries ranged from 60.28% to 129.2% with relative standard deviations(RSDs)within 0.29%-11%. The results demonstrated that the proposed method was sensitive and accurate, and suitable for the mycotoxins quantification in cogon rootstalk.