Uncertainty Evaluation of Determination of Microcystin MC-LR in Environmental Samples by Solid Phase Extraction-Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

To assess uncertainty of determination of MC-LR in environmental samples by solid phase extraction- ultra performance liquid chromatography- tandem mass spectrometry,the sources of the uncertainty were evaluated firstly,and the expanded uncertainty was calculated finally.The results show that when MC-LR concentration in the water samples was 0.50 μg/L,the expanded uncertainty was 0.00628 μg/L(k=2).

Rapid analysis of fifteen sulfonamide residues in pork and fish samples by automated on-line solid phase extraction coupled to liquid chromatography–tandem mass spectrometry

The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.

Multiresidue Method for Determination of 67 Pesticides in Water Samples Using Solid-Phase Extraction with Centrifugation and Gas Chromatography-Mass Spectrometry

A new multi-residue method based on solid-phase extraction (SPE) with centrifugation was developed for determination and quantitation of 67 pesticides in water samples. Two SPE cartridges were tested: Chromabond C18 and Oasis HLB. Parameters that influence the extraction efficiency such as the eluent volume, the sample loading volume, the addition of organic solvent to water sample, sorbent drying and elute concentration were optimized. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 2 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under the optimized conditions, this method showed good recoveries higher than 65% - 68% for the 67 analyzed pesticides using the C18 and HLB cartridges with relative standard deviations lower than 9.7% - 12.3%. Limits of quantification were between 2 and 20 ng.L–1. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.

Rapid Determination of Three Kinds of Microcystins in Environmental Water Samples by Disk SPE-Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A method of rapidly detecting three kinds of microcystins( MCs) in environmental water samples by using disk SPE- ultra high performance liquid chromatography- tandem mass spectrometry( UPLC- MS / MS) was established. Firstly,environmental water samples were extracted by disk SPE column( C_(18)),and three kinds of MCs were separated by Waters BEH C_(18) chromatographic column with acetonitrile- 0. 2% formic acid solution as the mobile phase. After the gradient elution separation,the external standard method was used for quantitative and qualitative analysis under MRM of UPLC- MS / MS. The results showed that the three kinds of MCs in the range of 0. 05- 10 μg / L showed good linear relation,and the correlation coefficients were higher than 0. 999 4,while the method detection limit was 0. 04 ng / L. Under 0. 1,1,and 5 μg / L standard addition for the same environmental sample,the average recovery was 82. 8%- 108. 8%,and the relative standard deviation of determination results was2. 1%- 10. 1%( n = 6). This method is rapid,sensitive and accurate,so it can be effectively applied in the monitoring of MCs in environmental water samples.

Liquid chromatography tandem mass spectrometry method for the estimation of lamotrigine in human plasma:Application to a pharmacokinetic study

A reliable,selective and sensitive liquid chromatography tandem mass spectrometry method was developed and validated for the quantification of lamotrigine in human plasma using lamotrigine13C3,d3 as an internal standard.Analyte and internal standard were extracted from human plasma by solid-phase extraction and detected in positive ion mode by tandem mass spectrometry with electrospray ionization（ESI） interface.Chromatographic separation was performed on a Chromolith s SpeedROD;RP-18e column（50-4.6 mm i.d.） using acetonitrile：570.1 mM ammonium formate solution（90：10,v/v） as the mobile phase at a flow rate of 0.500 mL/min.The calibration curves were linear over the range of 5.02-1226.47 ng/mL with the lower limit of quantitation validated at 5.02 ng/mL.The analytes were found stable in human plasma through three freeze（-20℃）-thaw（ice-cold water bath） cycles and under storage on bench-top in ice-cold water bath for at least 6.8 h,and also in the mobile phase at 10℃ for at least 57h.The method has shown good reproducibility,as the intra-and inter-day precisions were within 3.0%,while the accuracies were within 76.0% of nominal values.The validated LC-MS/MS method was applied for the evaluation of pharmacokinetic and bioequivalence parameters of lamotrigine after an oral administration of 50mg lamotrigine tablet to thirty-two healthy adult male volunteers.

Preparation of polypyrrole/nanosilica composite for solid-phase microextraction of bisphenol and phthalates migrated from containers to eye drops and injection solutions

This paper describes the electrodeposition of polyphosphate-doped polypyrrole/nanosilica nano-composite coating on steel wire for direct solid-phase microextraction of bisphenol A and five phthalates. We optimized influencing parameters on the extraction efficiency and morphology of the nanocomposite such as deposition potential, concentration of pyrrole and polyphosphate, deposition time and the nanosilica amount. Under the optimized conditions, characterization of the nanocomposite was inves-tigated by scanning electron microscopy and Fourier transform infra-red spectroscopy. Also, the factors related to the solid-phase microextraction method including desorption temperature and time, extrac-tion temperature and time, ionic strength and pH were studied in detail. Subsequently, the proposed method was validated by gas chromatography-mass spectrometry by thermal desorption and acceptable figures of merit were obtained. The linearity of the calibration curves was between 0.01 and 50 ng/mL with acceptable correlation coefficients (0.9956-0.9987) and limits of detection were in the range 0.002-0.01 ng/mL. Relative standard deviations in terms of intra-day and inter-day by five replicate analyses from aqueous solutions containing 0.1 ng/mL of target analytes were in the range 3.3%-5.4% and 5%-7.1%, respectively. Fiber-to-fiber reproducibilities were measured for three different fibers prepared in the same conditions and the results were between 7.3% and 9.8%. Also, extraction recoveries at two different concentrations were ≥96%. Finally, the suitability of the proposed method was demonstrated through its application to the analysis of some eye drops and injection solutions.

Determination of Aromatic Components of Rosa davurica Pall. by Headspace Solid Phase Microextraction Combined with GC-MS

[Objectives] To determine the aromatic components of Rosa davurica Pall. [Methods] 42 kinds of aromatic components were identified from the flowers of R. davurica by headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS). The main compounds were alcohols( 54. 88%) and aldehydes( 19. 55%). [Results] The top five components with the highest relative content were phenylethyl alcohol( 12. 69%),geraniol( 9. 85%),citronellol( 8. 80%),nerol( 7. 84%) and 2-n-pentylfuran( 7. 45%). [Conclusions] Headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS) can provide basis for further development and utilization of R. davurica.

Speciation of Volatile Selenium Species in Plants Using Gas Chromatography/Inductively Coupled Plasma Mass Spectrometry

Gas chromatography/inductively coupled plasma mass spectrometry (GC/ICP-MS) coupled with solid phase micro-extraction can provide a simple, extremely selective and sensitive technique for the analysis of volatile sulfur and selenium compounds in the headspace of growing plants. In this work, the technique was used to evaluate the volatilization of selenium in wild-type and genetically-modified Brassica juncea seedlings. By converting toxic inorganic selenium in the soil to less toxic, volatile organic selenium, B. juncea might be useful in bioremediation of selenium contaminated soil.

Determination of Sex Hormones in Antler Velvet by High Performance Liquid Chromatography Tandem Mass Spectrometry

Eighteen sex hormones in antler velvet were determined by high performance liquid chromatography tandem mass spectrometry.The solid phase extraction was applied to eliminating the matrix effect.The experimental conditions were examined and optimized.Under the optimal conditions,the proposed method provides the good linearities and determination limits（0.2―1.0 μg/kg） of the analytes investigated.The recoveries ranging from 72.3% to 149.5% were obtained for the target analytes at two concentration levels.This method was applied to the determination of eighteen sex hormones in different kinds of antler velvet samples and the obtained results are satisfactory.The results indicate that the proposed method is suitable for the determination of sex hormones in antler velvet samples.

Triacontyl modified silica gel as a sorbent for the preconcentration of polycyclic aromatic hydrocarbons in aqueous samples prior to gas chromatographic-mass spectrometry determination

Triacontyl modified silica gel as a sorbent coupled with gas chromatography-mass spectrometry(GC-MS) was developed to determine EPA prior 16 polycyclic aromatic hydrocarbons(PAHs) in water samples.Various parameters of solid-phase extraction such as organic modifier solvent,eluent,sample flow rate and volume were optimized.The developed method was found to yield a linear calibration curve in the concentration range of 0.05-8μg/L with respect to naphthalene,acenaphthylene,acenaphthene and 0.01-8μg/L for dibenz[a,h]anthracene and 0.05-14μg/L for fluorene,phenanthrene,anthracene and 0.01-14μg/L for the rest of analytes.Furthermore,the good accuracy and repeatability of the method made sure the requirements for achieving reliable analysis of PAHs in the environmental water samples,and the recoveries of optimal method were in the range of 80-120%except to higher volatility PAHs.C_(30)-bonded silica was proved to be an efficient sorbent for extraction of high molecular weight PAHs.

Analysis of nitrobenzene compounds in water and soil samples by graphene composite-based solid-phase microextraction coupled with gas chromatography–mass spectrometry

In this work, solid-phase microextraction coupled with gas chromatography–mass spectrometry was developed to determine trace levels of nitrobenzene compounds in water and soil samples. Graphene was chosen as the extraction material and its composite was coated on a stainless steel wire through sol–gel technique for the solid phase microextraction. The key parameters influencing the extraction efficiency were optimized. Under the optimal conditions, the linearity for the compounds was observed in the range of 0.02–15.0 mg/L for water samples, and 0.2–60.0 mg/kg for soil samples, with the correlation coefficients（r） of 0.9966–0.9987. The limits of detection of the method were 0.0025–0.005 mg/L for water samples, and 0.02–0.04 mg/kg for soil samples. The recoveries for the spiked samples were in the range of 72.0%–113.2%, and the precision, expressed as the relative standard deviations, was less than 12.1%.

An Automatic Solid Phase Extraction and Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry for Determination of Seven Microcystins at Ultra-Trace Levels in Surface Water

A method was developed for the detection of seven microcystins(microcystin-LR, RR, YR, LA, LY, LW and LF) in surface water using automatic solid-phase extraction(A-SPE) coupled with ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS). The automated solid-phase extraction system was used to extract microcystins(MCs) from water samples. UPLC-MS/MS was used to determine MCs concentrations in just 5 min. Method detection limits were from 0.3 to 0.9 ng/L, microcystin recoveries ranged from 83.8% to 114%, and the relative standard deviation(RSD) varied from 5.6% to 12.5%. This analytical approach was found to be simple, highly sensitive, accurate, which required little manual operation. Additionally, to validate this analytical method, A-SPE+UPLC-MS/MS was applied to characterize the concentration of MCs in Taihu Lake, Wuxi, China.

优化HS-SPME-GC-MS方法表征香菇不同成熟阶段的关键挥发性化合物

通过优化的顶空固相微萃取结合气相色谱-质谱联用技术鉴定香菇不同成熟阶段挥发性化合物,并采用气味活性值(odor activity value,OAV)和偏最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)进行分析。结果表明:最佳提取条件为1.0 g香菇样品在50℃提取25 min,解吸3 min;在香菇不同成熟阶段共鉴定出71种挥发性化合物,不同成熟阶段挥发性化合物种类和含量存在显著差异(P<0.05);通过PLS-DA和变量投影重要性(variable importance in projection,VIP)筛选出18种挥发性化合物,可作为区分香菇不同成熟阶段的挥发性生物标志物;OAV结果表明,有16种挥发性化合物为香气活性化合物,其中,1-辛烯-3-醇、3-辛醇、1-辛烯-3-酮、3-辛酮、苯乙醛、二甲基二硫醚、二甲基三硫醚、2,3,5-三硫杂己烷和1,2,4-三硫杂环戊烷同时满足VIP>1和OAV≥1,是香菇不同成熟阶段最重要的差异挥发性化合物。本研究为探究香菇成熟过程中香气形成机制提供一定理论依据。

MIL-101@MF复合材料-枪头高效固相萃取鸡蛋中酰胺醇类抗生素残留

将Fe-MIL-101通过聚偏二氟乙烯固定在三聚氰胺泡沫(MF)上制备MIL-101@MF复合材料,将其用做枪头固相萃取(PT-SPE)的吸附剂,并结合液相色谱-串联质谱法实现了鸡蛋中酰胺醇类(CAPs)抗生素的高效测定。对MIL-101@MF的形貌、晶体结构和官能团进行了表征,证实了Fe-MIL-101的成功合成并固定在MF上。优化了PT-SPE萃取条件,在多反应监测模式下,以基质标准曲线结合内标法同时测定氯霉素(CAP)、甲砜霉素(TAP)、氟苯尼考(FF)。由于氢键、π-π、静电等相互作用,MIL-101@MF对3种CAPs具有极高的萃取能力,萃取过程小于3 min,材料可重复使用60次。3种CAPs的定量下限为0.1μg/kg,加标回收率为78.2%~108%。采用该方法测定80批次鸡蛋样品,TAP的检出率2.50%,含量为0.21~1.2μg/kg;FF的检出率8.75%,含量为0.47~4.2μg/kg。该方法操作简便、灵敏度高且定量准确,有望应用于动物源性食品中多兽药残留的预处理中,为我国进出口食品安全残留监控提供技术支撑。

固相萃取-超高效液相色谱-串联质谱法测定蜂蜜中39种植物源性毒素

为有效评估蜂蜜中可能残留多种植物源性毒素的食品安全风险,建立和验证固相萃取-超高效液相色谱-串联质谱测定蜂蜜中39种植物源性毒素的检测方法。试样经0.1%甲酸水提取,HLB小柱净化,多反应监测模式检测,基质匹配外标法定量。本方法中39种植物源性毒素在各自浓度范围内线性关系良好,平均回收率介于78.7%~112.8%,相对标准偏差介于1.6%~15.2%(n=6)。该方法具有操作简单、检测通量大、灵敏度高等特点,能够满足蜂蜜中该类毒素监测的应用需求。在实际36批次样品的检测过程中,部分样品分别检出了不同含量的吡咯里西啶生物碱和闹羊花毒素III,证明蜂蜜中确具有残留该类植物毒素的风险。

基于GC-MS和MassHunter统计方法的芝麻油掺伪识别

目的提出了一种用于芝麻油掺伪识别的新方法。方法为实现芝麻油中掺伪的识别,对掺入不同比例的大豆油、玉米油、棕榈油的芝麻油的40个样品进行近红外分析,并且基于主成分分析对掺入油进行识别;应用固相微萃取-气相色谱/质谱联用仪(SPME-GC/MS)和Mass Hunter软件,对于玉米油掺伪芝麻油的风味质谱数据进行了研究。结果 Mass Hunter解卷积软件和Agilent Mass Profiler Professional数据统计软件更加灵敏地从复杂包埋的目标物剖析分离得到了独特的标记物。倍率变化(FC=5)分析和ANOVA(P=0.05)分析的结果以火山曲线表示,确定区分芝麻油和玉米油的独特特征标记物。基于此独特的标记物,通过主成分分析,可对纯芝麻油和掺伪芝麻油进行分类。结论试验证明通过统计分析风味质谱数据寻找特征标记物可解决芝麻油掺伪的识别问题。

固相萃取-液相色谱-串联质谱法测定海参中62种兽药残留

目的建立固相萃取结合高效液相色谱-串联质谱同时测定海参中62种药物的检测方法。方法样品加水分散后经1.0%甲酸乙腈溶液提取,PEP固相萃取柱净化后,采用WatersX-Bridge-C18色谱柱分离、0.2%甲酸水溶液-甲醇为流动相进行梯度洗脱,使用选择离子监测模式检测。结果62种兽药在0.50~100.00ng/m L范围内呈现出良好的线性关系,线性相关系数r^(2)在0.9953~1.0000范围内。方法检出限为0.25~2.50μg/kg;在3个不同浓度添加水平下,62种兽药的平均回收率在70.3%~119.0%,批内和批间的相对标准偏差(n=5)为0.13%~14.90%,均小于15.00%。将该方法应用于30批次海参样品的检测,其中4批次样品的喹诺酮检测结果阳性,检出量为5.30~28.00μg/kg,与国家标准方法的检测结果相比,该方法对于本次喹诺酮药物筛查的准确率为100%。结论该方法灵敏度高,准确度和精密度良好,满足我国兽药残留检测要求,可适用于海参中62种兽药多残留的定性定量分析检测。

分散固相萃取净化-超高效液相色谱-串联质谱法测定蜂蜜中双甲脒、杀虫脒及其代谢物

该研究建立了分散固相萃取-超高效液相色谱-串联质谱(dispersive solid phase extraction-ultra-performance liquid chromatography,UPLC-MS-MS)检测蜂蜜中双甲脒、杀虫脒及其代谢物残留的分析方法。蜂蜜样品2 g加入10 mL水溶液充分混匀,经1%(体积分数)氨化乙腈超声辅助提取后离心,利用N-丙基乙二胺、C18、氨基键合硅胶混合材料进行分散固相萃取净化,采用ACQUITY UPLC BEH C18(2.1 mm×50 mm,1.7μm)色谱柱分离,以甲醇和0.1%(体积分数)甲酸水溶液为流动相进行梯度洗脱,多反应监测模式正离子扫描分析。6种农药及其代谢物平均回收率为84.1%~113.8%,相对标准偏差为0.9%~6.0%,检出限为0.2~0.8μg/kg,定量限为0.7~2.5μg/kg。实验结果表明该方法快速简便、灵敏度高,适用于蜂蜜中双甲脒、杀虫脒及其代谢物残留同时分析。

基于HS-GC-IMS和HS-SPME-GC-MS的蛋白酶对豆粕挥发性风味的影响分析

为研究不同蛋白酶酶解对豆粕挥发性风味成分的影响,选用4种蛋白酶(碱性蛋白酶、中性蛋白酶、木瓜蛋白酶、风味蛋白酶)对豆粕进行酶解,采用顶空-气相色谱-离子迁移谱(Headspace-gas chromatography-ion mobility spectroscopy,HS-GC-IMS)和顶空固相微萃取-气相色谱-质谱(Headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)联用技术分析不同豆粕酶解物(Soybean meal hydrolysates,SMH)的挥发性风味成分,并结合主成分分析(Principal component analysis,PCA)、热图聚类和正交偏最小二乘判别法(Orthogonal partial least squares-discriminant analysis,OPLS-DA)对不同SMH进行分析。结果表明:碱性蛋白酶、中性蛋白酶、木瓜蛋白酶和风味蛋白酶酶解豆粕的挥发性风味成分存在较大差异。HS-GC-IMS鉴定出84种挥发性成分,筛选得到33种差异风味物质,发现酶解后酮类物质显著降低而醛类、醇类和酯类物质含量明显增加。PCA结果表明不同SMH之间的风味存在显著差异。最终通过OPLS-DA筛选出贡献较大的挥发性化合物,同时构建出可靠的用以鉴别SMH的模型。HS-SPME-GC-MS检测出103种差异风味物质,可用于区分不同SMH,被检出的挥发性组分中醛类、醇类和酮类等化合物为SMH风味的形成做出主要贡献,明晰了部分风味化合物形成的原因。PCA和聚类热图结果表明不同蛋白酶酶解对豆粕的挥发性风味物质的种类和含量有显著影响,其中,风味蛋白酶和木瓜蛋白酶对豆粕的风味改善最为显著。

固相萃取结合高效液相色谱-串联质谱测定胎便中14种全氟和多氟烷基化合物

全氟和多氟烷基化合物(PFASs)是一类人工合成的物质,由于其热稳定、疏水、疏油等优良性质而被广泛使用于生活和生产中.PFASs具有环境持久性、生物累积性、多种毒性等特性,且可以通过胎盘屏障进入到胎儿体内,进而对胎儿健康产生潜在危害.胎便中积累了妊娠期间暴露于胎儿的外源性化合物,可用于监测PFASs对胎儿的宫内暴露特征.本研究基于固相萃取结合高效液相色谱-串联质谱技术,建立了胎便中14种PFASs的分析方法.采用乙腈/水(9∶1,V/V)对0.2 g冻干胎便样品进行超声提取,提取液经Envi-carb和Oasis WAX小柱固相萃取,0.1%氨甲醇洗脱.以10 mmol·L^(−1)乙酸铵水溶液和乙腈作为流动相对目标化合物进行梯度洗脱,采用Acquity UPLC BEH C18色谱柱进行分离,基于多反应监测负离子模式采集,内标法定量.结果表明,在2、5、20 ng·g^(−1)的加标浓度下,14种PFASs的回收率为65%—149%,相对标准偏差为3%—22%,方法检出限(MDLs)为0.001—0.149 ng·g^(−1),方法定量限(MQLs)为0.003—0.495 ng·g^(−1).使用该方法测定了10个胎便样品,ΣPFASs浓度范围为<MDLs—2.49 ng·g^(−1).该方法操作简单、便捷、灵敏度高且定量准确,为系统性研究胎便中PFASs的赋存特征及暴露风险提供了技术基础.