Determination of halosulfuron-methyl residues and dissipation in wheat by QuEChERS and LC-MS/MS

A sensitive and rapid analytical method based on QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation and LC-MS/MS detection was developed for the analysis of halosulfuron-methyl residues in wheat. The recoveries of halosulfuron-methyl in both the wheat plant and grain ranged from 87% to 119% and from 75% to 97%, respectively, with relative standard deviations (RSDs) of 3–9%. The limit of quantification (LOQ) was 0.005 mg kg^?1 for wheat plant and 0.001 mg kg^?1 for wheat grain. The half-life of halosulfuron-methyl in the wheat plant was 0.9–9.5 days. The terminal residue levels of halosulfuron-methyl in wheat grain were below 0.01 mg kg^?1 at harvest.     

Development and validation of multi-residue method for determination of 412 pesticide residues in cotton fiber using GC-MS/MS and LC-MS/MS

The new global concept is to care about textiles and clothes safety to improve the protection of the human health and the environment from the harmful pesticide residues. Very few articles have been published for determination of several pesticide classes in cotton fibers in one multi-residue method. A simple, efficient, sensitive, accurate, and reliable multi-residue method was developed for the determination of 412 residual pesticides in cotton fibers using modified QuEChERS method with Liquid and Gas Chromatography coupled to Triple Quadrupole Mass Spectrometer (LC-MS/MS &; GC-MS/MS) for qualitative and quantitative analysis according to the international standards concepts. The developed method covered several pesticide classes, including 43 carbamates, 16 pyrethroids, 27 organochlorines (OCs), 54 organophosphorus (Ops), 31 urea derivatives, 7 Polychlorinated biphenyl (PCBs), 6 Neonicotinoid, and 228 other pesticides. Most of the target pesticides were listed in Oeko-Tex Standards, the EU Ecolabel for textile products, and the Egyptian recommendations of the Agricultural Pesticide Committee (APC-Egypt). The method optimization and validation were carried out according to the EU guidelines. The results were shown to be reliable where the corresponding average recoveries within the acceptable range of 70–120%; the relative standard deviations were less than 20%. The limit of quantitation (LOQ) of this method is 0.01 mg kg^?1 all pesticides except for 3 GC-compounds and 19 LC-compounds which have LOQ of 0.05 mg kg^?1.     

Development and validation of LC-MS/MS method with QuEChERS clean-up for detecting cannabinoids in foods and dietary supplements

ABSTRACT

a rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC) using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) clean-up for a variety of foods and dietary supplements (DS). QuEChERS is widely used in extraction or clean-up procedures to eliminate interference of matrices such as sugars, organic acids, lipids, and fatty acids. The samples were categorised into three types, and various pretreatment methods were compared for each type. In all types, the QuEChERS was superior and selected as the final pretreatment method. The optimised method was validated for specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, recovery, precision and accuracy. All of the validation results met the requirements of the international guidelines for all types of samples. The validated method was applied to 30 commercial food samples, CBD was detected in 17 samples, with 2 of them detected below the LOQ level and the rest detected in a range of 70 μg/kg to 31305 mg/kg (3.1%, w/w). Meanwhile, THC was detected in 14 samples; 2 of them were detected below the LOQ level and the rest detected in a 0.08–98.62 μg/g range. These results indicated that the validated method can be successfully applied for the determination of cannabinoids in a variety of samples. Furthermore, it will be useful for controlling the illegal distribution of cannabinoids.     

高效液相色谱串联质谱法分析烟草中15种农药残留

为检测烟草中的“吡蚜酮”等农药残留,建立了乙腈提取、分散固相萃取净化和高效液相色谱-质谱联用(LC-MS/MS)快速分析烟草中15种农药残留的方法.结果表明:15种农药在0.10,0.25和0.50 μg/g 3个加标水平的回收率为70.43% ～ 117.81%,相对标准偏差(RSD)为1.16%-13.89%,检出限为0.004～0.030 μg/g.该方法适合于批量烟草样品中多种农药残留的快速分析.     

Determinative and confirmatory method for residues of tetracyclines in honey by LC-MS/MS

A limited number of substances are authorised for the treatment of bees. Maximum residue limits (MRLs) are set for tetracyclines in several matrices, but not for honey. Nevertheless, tetracycline antibiotics may be used in order to prevent bacterial diseases and the loss of honey bee populations. In this study, a sensitive multi-residue LC-MS/MS method was developed and optimised for the quantitative and qualitative determination of tetracycline residues in honey. Homogenisation of samples under acidic conditions was performed and solid-phase extraction was carried out. The eluate was evaporated under nitrogen and dissolved in an aqueous methanol solution prior to filtration. A mobile phase composed of acetic acid–water and acetic acid–acetonitrile was used. Separation of tetracycline, oxytetracycline, chlortetracycline and doxytetracycline was achieved by using gradient elution on a C18 chromatography column. The analytical method was validated according to Commission Decision 2002/657/EC by the analysis of spiked samples around the recommended concentration of 20 μg kg^?1 by EURL Guidance Paper, December 2007. A matrix effect was observed, so quantification was based on an external matrix calibration curve. Calculated decision limits (CCα) were lower than 10 μg kg^–1 for all tetracyclines. Good linearity, repeatability and within-laboratory reproducibility were achieved.     

卷烟主流烟气中挥发性醛酮的LC-MS/MS分析

采用2,4-二硝基苯肼衍生-LC-MS/MS法测定了32种卷烟样品主流烟气中的甲醛、乙醛、丙烯醛、丙酮、丙醛、巴豆醛、甲基丙烯醛、2-丁酮、丁醛、苯甲醛、戊醛、己醛.结果表明:①方法的检测限为0.1～0.5 ng/mL,回收率在91.6%～100.3%之间,相对标准偏差为3.28%～7.86%;②卷烟样品主流烟气的挥发性醛酮成分中主要为乙醛和丙酮,苯甲醛、已醛含量较小;③与进口烟相比,国产烤烟型卷烟主流烟气中的挥发性醛酮含量相对较高,混合型卷烟的相对较低;④不管是烤烟型还是混合型,焦油量高的卷烟主流烟气中的挥发性醛酮含量均相对较高.     

液相色谱串联质谱法测定食品中红曲色素

采用液相色谱串联质谱法测定了食品中红曲红胺、红曲红素、红曲素、红曲黄素的含量,并选择离子检测进行阳性确证。液体试样用水超声提取,离心定容后,固体和半固体样品采用水溶解定容,提取液再经固相萃取柱净化,样液经洗脱定容后,供液相色谱-质谱/质谱仪测定和确证,外标法定量。该方法的最低检出限、线性范围和方法回收率分别为:1.0 mg/kg、1.0～100.0 mg/kg和89.3%～94.3%。     

Development and validation of an LC-MS/MS method for the simultaneous analysis of 28 specific narcotic adulterants used in dietary supplements

The purpose of this study was to develop a method to analyse the concentration of multiple illegal narcotics present in dietary supplements. To this end, we established and optimised a procedure using LC-MS/MS simultaneously to analyse 28 narcotic compounds in various forms of dietary supplements, including powders, tablets, liquids and capsules. In addition, candy and cookies that have also had detected cases of adulteration were also analysed. The specificity, linearity, accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ), stability and recovery for these methods were validated accordingly. The LOD and LOQ of the LC-MS/MS ranged from 0.01–50.0 to 0.03–100 ng g^?1, respectively. The linearity of these results was good (r² > 0.99), with intra- and inter-day precision values of 0.2–5.2% and 0.2–4.8%, respectively. Further, the intra- and inter-day accuracies of this method were 97.0–103.4% and 94.6–103.1%, respectively. The stability RSD was less than 7.8%. The mean recovery for this LC-MS/MS procedure was 81.1–117.4%, with an RSD less than 9.8%. Following the validation of our method, we analysed 47 commercially available dietary supplements obtained in Korea. Whilst none of these samples had detectable amounts of the 28 specified narcotic adulterants, our novel LC-MS/MS procedure can be utilised comprehensively and continually to monitor illegal drug adulteration in various forms of dietary supplements.     

Development and validation of an LC-MS/MS method for the quantification of tiamulin,trimethoprim, tylosin,sulfadiazine and sulfamethazine in medicated feed

A new multi-compound method for the analysis of veterinary drugs, namely tiamulin, trimethoprim, tylosin, sulfadiazine and sulfamethazine was developed and validated in medicated feeds. After extraction, the samples were centrifuged, diluted in Milli-Q water, filtered and analysed by high performance liquid chromatography coupled to tandem mass spectrometry. The separation of the analytes was performed on a biphenyl column with a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in Milli-Q water. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/EC. Method performances were evaluated by the following parameters: linearity (R² < 0.99), precision (repeatability <14% and within-laboratory reproducibility <24%), recovery (73.58–115.21%), sensitivity, limit of detection (LOD), limit of quantification (LOQ), selectivity and expanded measurement uncertainty (k. = 2). The validated method was successfully applied to the 2 medicated feeds obtained from the interlaboratory studies and feed manufactures from Spain in August 2017. In these samples, tiamulin, tylosin and sulfamethazine were detected at the concentration levels declared by the manufacturers. The developed method can therefore be successfully used to routinely control the content and homogeneity of these antibacterial substances in medicated feed.

Abbreviations

AAFCO – Association of American Feed Control Officials; TYL – tylosin; TIAM – tiamulin fumarate; TRIM – trimethoprim; SDZ – sulfadiazine; SMZ – sulfamethazine; UV – ultraviolet detector; FLD – fluorescence detector; HPLC – high performance liquid chromatography; MS/MS – tandem mass spectrometry; LOD – limit of detection; LOQ – limit of quantification; CV – coefficient of variation; SD – standard deviation; U – uncertainty     

Rapid multiresidue determination of pesticides in livestock muscle and liver tissue via modified QuEChERS sample preparation and LC-MS/MS

ABSTRACT

Many multiresidue methods for the determination of pesticides in vegetables and fruits have been reported to date. However, few such methods have been employed to investigate pesticide residues in animal tissue. In this study, an LC-MS/MS multiresidue method coupled with modified QuEChERS extraction was developed and validated for the investigation of eight pesticide residues: prallethrin (PR), resmethrin (RMT), imidacloprid (IMC), diflubenzuron (DFB), cyromazine (CYR), etofenprox (EFP), dinotefuran (DNT) and phthalthrin (PTLT). This method involves initial extraction in a water/acetone system, the addition of salts and a subsequent extraction/partitioning step and, finally, a clean-up step utilising dispersive solid-phase extraction (SPE). The mean recoveries of seven of the pesticides (the exception being CYR) ranged between 74.7% and 113.5%, and the CVs of the livestock tissue – bovine, swine, and chicken muscle and liver tissue spiked at 10 ng g^–1 (50 ng g^–1 for RMT and DNT) and 100 ng g^–1 – were < 13.8%. The recoveries of CYR in all muscle and liver spiked samples ranged from 56.9% to 78.3%, while those of RMT in swine liver were > 120%. Therefore, this method was considered as being unsuitable for the investigation of these samples. The limits of quantitation (LOQs) of seven of the investigated pesticides (the exception being swine liver) in the tissue samples ranged from 0.9 to 15.2 ng g^–1. We therefore concluded that this LC-MS/MS multiresidue method is a valid and suitable for the investigation of seven pesticides in animal tissue, but it is unsuitable for the analysis of CYR in all animal tissues and RMT in swine liver tissue.     

液相色谱-串联质谱法测定豆类中左旋多巴

文章建立一种豆类中左旋多巴的液相色谱-串联质谱测定方法。样品经0.3 mol/L乙酸水溶液超声提取,Agilent Proshell 120 SB-C18(2.1 mm×150 mm,2.7μm)色谱柱分离,以0.1%甲酸水-甲醇为流动相进行梯度洗脱,多反应监测(MRM),内标法定量。结果表明,左旋多巴在0.1~5.0 mg/L范围内线性关系良好,相关系数为0.9994,检出限为1.5 mg/kg,定量限为5.2 mg/kg,方法的平均加标回收率为96.9%~105.5%,日内精密度和日间精密度均小于4%,具有操作简单、灵敏度高、准确度高、重现性好等特点,能够很好满足豆类中左旋多巴含量的检测需要。     

Multiresidue automated turbulent flow online LC-MS/MS method for the determination of antibiotics in milk

A fast and reliable multiresidue method is reported for the identification and quantification of 36 different compounds from seven different classes of antibiotics (aminoglycosides, sulfonamides, macrolides, quinolones, tetracyclines, lincosamides and trimethoprim) in milk. Automated online sample cleanup was applied using turbulent flow chromatography (Transcend TLX system), directly coupled to a mass spectrometer (MS/MS) for sensitive and specific detection. The method involved a simple extraction/protein precipitation using acetonitrile, followed by centrifugation and filtration. After this preliminary step, the extract was injected into the TLX-ESI-MS/MS using optimised turbulent flow and liquid chromatography (LC) conditions. Single-laboratory validation of the method was carried out according to the Directive 2002/657/EC, clearly demonstrating the suitability of this method for quantitative determination of this wide range of antibiotics in milk. A small survey, which covered milk samples of different origin and varied fat content, demonstrated the robustness of this method and its suitability for enforcement purposes.     

液相色谱-串联质谱法测定腐乳中的生物胺

建立了一种使用液相色谱-串联质谱（LC-MS/MS）技术检测腐乳中9种生物胺的方法。样品经5%三氯乙酸水溶液提取后,进行液相色谱-串联质谱法测定,采用外标法定量。对检测方法进行方法学验证,9种生物胺在质量浓度为10～200 ng/mL范围内线性相关系数R2＞0.999,方法检出限为0.03 mg/kg,定量限为0.1 mg/kg,回收率在85%～101%之间,相对标准偏差（RSD）在0.9%～4.8%之间。该方法结果精密、准确、重复性好、操作简单,适用于腐乳中9种生物胺的测定。     

Validation and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw using LC-MS/MS

An efficient analytical method was developed and validated using a modified QuEChERS method and LC-MS/MS for the detection and quantification of neonicotinoid insecticide residues in rice whole grain and rice straw. The samples were extracted using acetonitrile and cleaned up by dispersive solid-phase extraction. Validation based on five fortification levels showed good recoveries of neonicotinoids ranging from 75% to 116 % and 60% to 105 % for rice whole grain and straw, respectively. The precision ranged between 3% and 17 %, and 2% and 10 % for grain and straw, respectively. The limit of detection was from 0.007 to 0.0084 mg kg^?1 and 0.005 to 0.15 mg kg^?1 and the limit of quantification was in the range of 0.024–0.028 mg kg^?1 and 0.016–0.051 mg kg^?1 for rice whole grain and rice straw, respectively. Monitoring of farm gate samples indicated that, out of 24 samples, 1 rice whole grain sample was contaminated with thiamethoxam residues (0.07 mg kg^?1).     

液相色谱-串联质谱测定食醋中生物胺含量

为了检测食醋中生物胺,建立了液相色谱-串联质谱（LC-MS/MS）的检测方法,检测食醋中精胺、亚精胺、尸胺、腐胺、组胺、酪 胺、色胺7种生物胺。 结果表明,不同品牌的食醋生物胺总量差异较大,生物胺总量最高可达到229.98 mg/L,而最低为13.48 mg/L, 酪胺含量（0.96～84.83 mg/L）较高;组胺含量（0.80～9.08 mg/L）较低;不同食醋中精胺（3.01～9.44 mg/L）和尸胺（1.38～15.40 mg/L） 含量不同;样品中未检出色胺。 相关性分析结果显示,腐胺与尸胺、组胺与酪胺之间具有显著相关性（P＜0.01）。     

Multiresidue method for detection of pesticides in beef meat using liquid chromatography coupled to mass spectrometry detection (LC-MS) after QuEChERS extraction

Beef meat is an important food that can be contaminated by pesticides. This study aimed to optimize a multiresidue method for identification and quantification of pesticides in beef meat by liquid chromatography coupled to mass spectrometry detection (LC-MS). The extraction and clean-up procedures were adapted from the QuECHERS method. From the 188 analytes tested, the method was validated as qualitative method for 19 compounds and as quantitative method for 152 compounds. The results were satisfactory, yielding coefficients of variation of less than 20% and recoveries ranging from 70% to 120% and expanded uncertainty of less than 50%. The quantification limit was typically 10 µg kg^?1 (but 25 µg kg^?1 for 12 of the compounds) and the detection limit was 5.0 µg kg^?1. Thirty-two real samples of commercialized beef meat were analyzed without any residual pesticide being found. Thus, the results showed that the multiresidue method for detecting 171 pesticides, using adapted QuECHERS for extraction and LC-MS for detection, is suitable for analyzing beef meat.     

Development of an LC-MS/MS method to quantify sex hormones in bovine milk and influence of pregnancy in their levels

Hormones work in harmony in the body, and this status must be maintained to avoid metabolic disequilibrium and the subsequent illness. Besides, it has been reported that exogenous steroids (presence in the environment and food products) influence the development of several important illnesses in humans. Endogenous steroid hormones in food of animal origin are unavoidable as they occur naturally in these products. The presence of hormones in food has been connected with several human health problems. Bovine milk contains considerable quantities of hormones and it is of particular concern. A liquid chromatography–tandem mass spectrometry (LC-MS/MS) method, based on hydroxylamine derivatisation, has been developed and validated for the quantification of six sex hormones in milk [pregnenolone (P₅), progesterone (P₄), estrone (E₁), testosterone (T), androstenedione (A) and dehydroepiandrosterone (DHEA)]. This method has been applied to real raw milk samples and the existence of differences between milk from pregnant and non-pregnant cows has been statistically confirmed. Basing on a revision of existing published data, it could be concluded that maximum daily intakes for hormones are not reached through milk ingestion. Although dairy products are an important source of hormones, other products of animal origin must be considered as well for intake calculations.     

LC-MS/MS法测定保健食品中左卡尼汀的含量

目的 建立保健品中左卡尼汀的LC-MS/MS的测定方法。方法 待测样品经超声提取、稀释后, 分别采用CAPCELL PAK CR色谱柱和PC HILIC色谱柱进行分离, 最后用LC-MS/MS进行检测。 结果 使用CAPCELL PAK CR法检测左卡尼汀能够得到更高的灵敏度, 线性范围为0~200 ng/mL, 相关系数为r=0.9995。结论 该方法灵敏度高、准确、重现性好, 可以用于一些保健食品中左卡尼汀的含量检测。     

液相色谱-串联质谱法检测速冻调制肉制品中糖皮质激素类药物残留

建立液相色谱-串联质谱法检测速冻调制肉制品中糖皮质激素类药物残留的方法。样品经乙酸乙酯提取后,过Silica固相萃取柱净化,最后用乙腈定容,经液相色谱-串联质谱仪测定。样品采用外标峰面积法进行定量,该方法的最小检出限量分别为0.2、0.5、1.0μg/kg,定量限分别为0.5、1.0、2.0μg/kg,添加回收率范围为85.0%～96.4%,RSD为2.3%～6.1%。     

LC-MS/MS法测定人血浆中曲司氯铵的浓度

目的建立测定人血浆中曲司氯铵浓度的LC-MS/MS方法。方法血浆样品经液-液提取后,以甲醇(含0.1%乙酸):水(含0.1%乙酸+2.5mmol/L甲酸铵)(80:20)为流动相,使用Agilent1100VL型离子阱质谱仪,电喷雾离子源正离子模式,采用多反应离子监测方式测定曲司氯铵(MRM,m/z392→164+182)。结果血浆中曲司氯铵线性范围为0.1～10.0ng/mL,定量下限为0.1ng/mL,准确度85%～115%,日内、日间精密度(RSD)±15%。结论该方法准确,专属性强,可用于曲司氯铵药动学研究。