Modified QuEChERS method for 24 plant growth regulators in grapes using LC-MS/MS

A multiresidue analytical method was developed for grapes for the following 24 plant growth regulators: 1-naphthylacetamide, 2,3,5-triiodobenzoic acid, 2,4,5-T, 2-naphthoxyacetic acid, 3-indolylacetic acid, 4-(3-indolyl)-butyric acid, 4-chlorophenoxyacetic acid, 4-nitrophenol, 6-benzylaminopurine, N6-isopentenyladenine, butralin, chlormequat chloride, chlorphonim-Cl, cloprop, forchlorfenuron, gibberellic acid 3, gibberellic acid 4, gibberellic acid 7, inabenfide, mepiquat chloride, paclobutrazol, prohydrojasmon, thidiazuron and uniconizole-P. The compounds were extracted from grape samples using an extraction method modified from the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method. Liquid chromatography – tandem mass spectrometry was used for the detection and quantification of the compounds. Validation of the method was performed by using recovery studies at both intra-day and inter-day intervals, as well as by evaluation of the matrix effect, limit of quantification, trueness and precision. We used matrix-matched calibrations for the quantification of the compounds, which all resulted in determination coefficients (r²) higher than 0.995. The limit of quantification ranged from 0.1 to 5 ng/mL. Recovery studies using three spiking concentrations at varying levels showed recoveries of 70.2–112.6% and 67.5–101.8% at intra-day and inter-day intervals, respectively. Relative standard deviations were below 20% for the recovery studies. The extraction method were further validated by performing recovery study and matrix effect test in six different grape varieties from Taiwan and the United States and all resulted in comparable results. Application of the established method to 50 grape samples, resulted in the detection of chlormequat chloride and forchlorfenuron residues in the tested grapes. The results of the method validation and real sample analysis shows the extraction method is therefore suitable for routine monitoring of residue in grapes.     

液相色谱-串联质谱法同时测定丹参中139种农药残留

目的:采用液相色谱-串联质谱法建立丹参中农药多残留的测定方法。方法:样品经改良的QuEChERS方法提取,采用分散固相萃取(d-SPE)二次净化法净化,并采用液相色谱-串联质谱技术在多反应监测(MRM)模式下测定,内标法定量。结果:丹参中139种农药在0. 005～0. 2 mg/L范围内线性关系均良好;在10、50和100μg/kg添加水平下,除了噻菌灵回收率偏低(67. 2～67. 9)外,其余农药的平均回收率为70. 2%～126. 1%,相对标准偏差(RSD)为1. 2%～19. 5%,139种农药的检测限为0. 005～0. 05 mg/kg。结论:该方法样品前处理简单快速,灵敏度、准确度和精密度均符合农药多残留检测技术的要求,适用于丹参中139种农药残留的快速筛查测定。     

Use of Quick,Easy, Cheap,Effective, Rugged & Safe (QuEChERS) and molecular imprinted polymer followed by gas chromatography with tandem mass spectrometry for the quantitative analysis of polycyclic aromatic hydrocarbons (PAH4) in complex health supplements

A gas chromatography-tandem mass spectrometry sensitive and selective method based on a combination of QuEChERS and subsequent molecularly imprinted polymer (MIP) technology was validated for the analysis of polycyclic aromatic hydrocarbons in complex dry extracts of Eleutherococcus senticosus, Salvia officinalis, Camellia sinensis, Zingiber officinale, Uncaria tomentosa, Humulus lupulus, Pinus sylvestris L., Spirulina maxima, propolis and royal jelly. The method has been optimized using gas chromatography coupled to tandem mass spectrometry. An additional sample treatment of the dry extracts, based on the combined use of MIP-SPE and QuEChERS, was required because of the strong matrix effect observed related to interferences affecting analyte quantification. Estimation of the method detection limit and quantification limit was carried out for validation. The LOQs were 0.2 ng g⁻¹ for benz[a]anthracene, 0.3 ng g⁻¹ for benzo[a]pyrene and 0.4 ng g⁻¹ for benzo[b]fluoranthene and chrysene; and the LODs were 0.07, 0.09 and 0.1 ng g⁻¹ respectively. Recoveries were in the range of 88.5 % for B[b]F, to 114 % for B[a]A, and % RSD was < 14 % in all cases. The method was applied in routine analysis to a wide variety of dry extracts from EU and non-EU manufacturers.     

Development of HPLC-DAD method for determination of neonicotinoids in honey

After the EU banned the use of the neonicotinoids in flowering crops that honeybees might visit, there has been an increased interest in determining the neonicotinoid residues in honeybee products such as honey. The aim of this study was to develop and optimize an HPLC-DAD analytical method with dispersive liquid–liquid microextraction (DLLME) and QuEChERS sample preparation procedures for the simultaneous analysis of seven neonicotinoids (dinotefuran, nitenpyram, thiametoxam, clothianidin, imidacloprid, acetamiprid and thiacloprid) in honey samples. The liquid chromatographic conditions were optimized by Response surface methodology with Box–Behnken design and Derringer's desirability. The optimized method was validated to fulfill the requirements of SANCO/12571/2013 standard for both sample pretreatment procedures providing results for accuracy (73.1–118.3%), repeatability (3.28–10.40%) and within-laboratory reproducibility (6.45–17.70%), limits of detection (1.5–2.5 μg kg⁻¹) and quantification (5.0–10.0 μg kg⁻¹) with the use of matrix-matched calibration to compensate the matrix effects. For the first time 104 honey samples from Vojvodina were analyzed. The presence of thiacloprid, imidacloprid and thiametoxam was found in a small number of samples implicating the usefulness of ongoing control of honey. Residues were confirmed by LC–MS/MS.     

Systemic and non-systemic pesticides in apples from Kazakhstan and their impact on human health

Understanding the behavior of pesticides used during fruit cultivation is important for effectively and safety applying to minimize the risk exposure of consumer. The aim of this study was estimated the level of pesticide in 80 apple samples collected from the South Kazakhstan. Additionally, the peel and pulp was investigated. Around 50% samples contained 24 pesticides, ranging 0.006–0.62, 0.005–0.46 and 0.02–1.38 mg/kg in whole apples, pulp and peel, respectively. The penetration factor pesticide peel/pulp was calculated and ranged 1.7–10.9 for kresoxim methyl and triazophos, respectively. Acute (aHI) and cumulative (cHQ) exposure health risks associated with consuming these pesticides in whole fruit, pulp and skin were estimated. The triazophos, chlorpiryfos and cyhalothrin exceeded safety ARfD: 830, 136 and 112% for adults, whereas for infants 4514, 742 and 609%. The cHQ exposure were the highest in peel for AChE inhibitors: 999%, and sodium channel modulators 123% for adults.     

Quantitative analysis of 3,4-dimethylmethcathinone in blood and urine by liquid chromatography–tandem mass spectrometry in a fatal case

We report here the quantitative analysis of cathinone-type designer drug 3,4-dimethylmethcathinone (3,4-DMMC) in blood and urine using liquid chromatography–tandem mass spectrometry (LC–MS/MS) in a fatal case. Abuse of 3,4-DMMC is widespread and a global issue. However, to date, there have been no reports of 3,4-DMMC-related deaths. We encountered a death in which 3,4-DMMC was thought to play a causative role, and successfully identified this designer drug from biological samples by using LC–MS/MS and QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method. For standard samples, detection of 3,4-DMMC in human blood and urine samples in the calibration range (5–400 ng/mL) was successful with recoveries of 85.9−89.4% (blood) and 95.8−101% (urine), limits of detection of 1.03 (blood) and 1.37 ng/mL (urine) and limits of quantification of 5.00 (blood) and 5.38 ng/mL (urine). The concentrations of 3,4-DMMC in blood (external iliac vein) and urine in the case were 27 mg/L and 7.6 mg/L, respectively. Some metabolites, including 3,4-dimethylcathione (DMC) and β-ketone reduced metabolites (β-OH-DMMC and β-OH-DMC), were detected in both blood and urine.     

Development of a comprehensive analytical method for furanocoumarins in grapefruit and their metabolites in plasma and urine using UPLC-MS/MS: a preliminary study

To develop a comprehensive analytical method for photoactive furanocoumarins, grapefruit (whole, flesh, peel and juice) was extracted using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method. Seven furanocoumarins: bergaptol, psoralen, 8-methoxypsoralen, bergapten, 6′,7′-dihydroxybergamottin (6′,7′-DHB), epoxybergamottin and bergamottin were determined in grapefruit using UPLC-MS/MS. The concentrations of furanocoumarins in the plasma and urine of six healthy young adults before and after ingestion of grapefruit or grapefruit juice were also determined. Recovery rates of furanocoumarins by QuEChERS method from matrix spike sample and laboratory calibrate sample were 125.7?±?25.4% and 105.7?±?6.3%, respectively. Bergamottin and 6′,7′-DHB were predominant compounds in grapefruit flesh, juice and plasma, while bergaptol and 6′,7′-DHB were major compounds detected in the urine. The results demonstrated that bergamottin and 6′,7′-DHB were metabolized to bergaptol. Overall, the analytical methods developed in the present study can be applied to the analysis of various furanocoumarins in plant sources and biological samples.     

白僵菌属的分类及种的形态特征

白僵菌属建属近一个世纪了，但其属内种的分类一直存在较大的分歧，种的最后分类没有定论，本文对白僵菌属的６个种进行了形态学的描述     

碳酸锂对荷瘤小鼠的抑瘤防瘤及抗氧化作用研究

为探讨碳酸锂（Ｌｉ２ＣＯ３）对肿瘤是否有防治作用，选择两种荷瘤小鼠（肝癌Ｈ２２、肉瘤Ｓ１８０）对其进行了抑瘤防瘤实验研究，同时测定两种荷瘤小鼠血细胞超氧化物歧化酶（ＳＯＤ）活性、血浆丙二醛（ＭＤＡ）含量，初步探讨碳酸锂对荷瘤小鼠体内氧化及抗氧化系统的影响，并与环磷酰胺（ＣＰ）的毒副作用进行了比较。结果表明，Ｌｉ２ＣＯ３在剂量设计范围内未见明显的毒副作用。抑瘤防瘤实验中，对Ｈ２２和Ｓ１８０两种肿瘤均有明显的抑制作用；可提高两种荷瘤小鼠血细胞的ＳＯＤ活性，降低ＭＤＡ含量；同时对荷瘤小鼠血液白细胞（ＷＢＣ）水平无影响，并可降低荷瘤小鼠的骨髓细胞微核率（ＭＮＦ）。而ＣＰ则有肯定的降ＷＢＣ作用和致突变作用。     

175名二硫化碳作业工人神经肌电图分析

对１７５名二硫化碳作业工人进行神经系统及神经肌电图检查。结果发现，二硫化碳作业工人的神经肌电图改变符合远端轴索病肌电图的特点，神经肌电图检查对二硫化碳作业工人周围神经损伤有早期诊断价值，而且还表现出二硫化碳暴露对周围神经损伤的剂量—效应关系。