基于NIST数据库的农药残留裂解谱库的建立及应用

为了保障食品和中药材的质量安全,采用气相色谱-三重四级杆质谱建立200余种农药及有机污染物质谱裂解数据库及优化的MRM数据库,通过谱库检索技术可以实现食品和中药材中未知组分的非靶标筛查及定性。在对未知组分进行谱库检索后,通过GC-QQQ方法比较未知组分与标准图谱的保留时间、一级质谱的萃取离子流色谱图镜像匹配。采用本研究建立的谱库及未知物筛查方法可对实际样品中的未知污染物进行快速筛查及确认。     

液相色谱-串联质谱结合谱库检索测定猪组织中13种氟喹诺酮类药物

采用MRM→IDA→EPI→谱库检索模式建立了猪组织中13种氟喹诺酮类药物的液相色谱-电喷雾串联质谱多残留检测方法,结合谱库检索功能同时实现了定性定量分析.组织样品经N,N-二甲基甲酰胺-乙腈混合溶液提取,Waters HLB柱净化,本方法13种氟喹诺酮类药物的线性范围为1.0～5000.0 μg/kg,线性相关系良好...     

固相萃取-气相色谱-质谱联用法筛查食用菌中的农药残留

采用气相色谱-质谱联用结合NAGINATA™软件建立了筛查食用菌中多种农药残留的分析方法。采用乙腈提取,Carbon-NH2固相萃取小柱净化,气相色谱-质谱联用检测后NAGINATA™软件全智能分析,对照每个化合物的质谱质量精度以及质谱谱图的谱库给出匹配度,通过保留时间锁定对化合物作定性判断。结果表明,18 种农药在香菇中检出限为0.001～0.050 mg/kg;平均回收率为77%～110%;相对标准偏差为1.1%～6.9%。应用所建立的方法对35 个市售食用菌样品进行了筛查,检测出2 种农药残留,残留量均低于GB 2763-2014《食品中农药最大残留限量》的限量。该方法操作便捷、快速高效,适用于食用菌中农药多残留的快速筛查。     

β-谷甾醇异构体的分离和初步鉴定

采用HPLC对植物甾醇标准品和甾醇样品进行分离,发现一未知组分.该未知组分随着β 谷甾醇的富集而增多.通过GC MS分析鉴定并检索Wiley和Nist谱库,可初步确定该未知组分是β 谷甾醇的异构体.     

基于衰减全反射法的纺织纤维红外光谱库的建立与应用

采用衰减全反射法制样,对不同成分组成、不同混纺比的纺织面料进行红外光谱扫描,利用化学分析法结果对谱图进行编号,自建了1000多个样本组成的纺织纤维红外光谱库。同时探讨了利用谱库检索功能对未知样品的纤维成分进行快速无损检测的可行性。     

植物源性食品中农药残留筛选平台研究

目的针对植物源性食品中的未知农药残留,在原农药残留筛选平台的基础上,采用气相色谱-三重四极杆质谱联用仪和UPLC-Q-Orbitrap两种色质技术并配合商业和自建农药筛查库建立共1200多个农药及其降解产物的筛选平台,满足未知农残的快速筛选要求。方法建立筛选平台相关筛选方法和准则,并通过两次欧盟国际比对(EUPT)对该平台进行验证评估。结果该平台在24 h内可完成农残筛选,筛选方法基于农药数据库和空白基质,两次能力验证中阳性化合物的检出率均在90%以上且结果无假阳性。结论该平台利用串联质谱和高分辨质谱的高选择性,结合农药数据库和智能筛选软件,在无标准参考物质的情况下实现非靶向农药的快速筛查。     

织物傅里叶变换衰减全反射红外光谱库的建立及应用

针对常规方法鉴别纯纺织物及预测混纺织物组分含量工序多、耗时长且污染环境的问题,采用傅里叶变换红外光谱仪,结合衰减全反射(ATR)附件测试各纯纺及二组分混纺织物的傅里叶变换衰减全反射红外光谱(ATR-IR)图,并从已测的753个样品中筛选出正反经纬组分一致的纯纺及混纺织物样品205个,建立了涤纶/棉、涤纶/羊毛、涤纶/锦纶、蚕丝/棉和涤纶/粘胶等纯纺及混纺织物的ATR-IR谱库。并利用自建谱库的检索功能,对20个未知纤维织物样品进行快速无损鉴别及含量预测。研究表明:对于纯纺织物,识别准确率为100%;对于混纺织物,当误差≤3% 时,通过T检验,其定量预测结果与国标法测定值无显著差异,方便了样品的快速检验与含量预测。     

基于保留指数原理结合气相色谱-三重四极杆质谱法快速筛查蔬菜中农药残留的方法研究

目的建立气相色谱-三重四极杆质谱联用法快速筛查蔬菜中农药残留的方法。方法利用正构烷烃C9-C33标准溶液,结合气相色谱-三重四极杆质谱联用仪及其Smart Database Pesticides数据库建立仪器数据采集方法。选用9种农药为目标物,试样经QuEChERS方法进行萃取净化后,建立质谱多反应监测(multiple reaction monitoring,MRM)方法,进行定性、定量分析。结果采用空白样品添加标准溶液制得质量浓度为0.01、0.05、0.10mg/kg的样品,基于保留指数所建立的方法准确定性出待测9种农药,并测得方法的平均回收率为72.0%~118.8%。结论该方法简便、快速、成本低,具有较好的适用性,对监测农产品中农药的使用种类,更加全面合理地制定农产品中农残限量范围具有参考价值。     

顶空-气相色谱/质谱法测定互叶白千层茶树精油中的挥发性成分

目的 建立顶空-气相色谱/质谱法测定茶树精油中的挥发性成分的分析方法。方法 茶树精油样品用正己烷溶解,放入顶空迚样瓶中,用顶空-气相色谱/质谱迚行测定。结果 用该方法共分离了15个组分,用NIST Chemical Structures库和Wiley Library质谱库迚行检索,以质谱相似度和利用标准品对部分主要成分迚行迚一步确认,最终确认13种主要成分;采用峰面积归一化法确定各组分峰的相对含量,有效成分含量占总流出物的98.46%。结论 该方法快速、准确、灵敏,适合茶树精油等精油类物质中挥发性成分的测定。     

超高效液相色谱-四级杆-飞行时间质谱法快速筛查与确证蔬菜水果中的多种农药残留

目的应用超高效液相色谱-四极杆-飞行时间质谱技术,针对GB 2763—2014《食品安全国家标准食品中农药最大残留限量》规定的农药残留,整合多种检测方法,建立无需标准品的快速筛查与确证蔬菜、水果中多种农药残留的方法。方法通过一级精确质量数据库比对样品准分子离子的精确质量数、同位素分布与丰度,对蔬菜、水果中农药残留进行初筛,通过实际测定样品的二级谱图与二级谱库中谱图进行比对或通过图谱解析方法进行确证。结果通过基质加标进行了方法验证,10.0和50.0μg/kg添加水平检出率均为100%,90%以上的农药化合物回收率在70%~120%,并且相对标准偏差(RSD)≤20%(n=5)。对30份蔬菜、水果样品进行筛查与确证,共检出27种农药残留,并依据GB 2763—2014进行了判定,共有2份样品超标。结论该方法的灵敏度、准确性和重复性良好,可以在较短的时间内,甚至在没有标准品的情况下,对GB 2763—2014中数百种农药进行筛查与确证,可为食品安全监管提供有效保障。     

QuEChERS-TOF-MS/MS 检测食品农产品中残留的未知农药

目的 利用 LC-Triple TOF 仪器建立筛查食品/农产品中未知农药的分析方法。 方法 采用 QuEChERS 法对多种食品/农产品中残留的农药进行提取, PeakView 软件全智能分析, 对照每个化合物的 TOF-MS 质量精度及同位素分布情况, 以及对照化合物 TOF-MS/MS 与标准品谱库, 给出匹配度, 对照化合物与标准品的保留时间, 对化合物作出定性判断。同时利用 MultiQuant 软件对检出的化合物含量结果进行定量分析。结果 该方法通过自动校正系统, 能自动进行批校正, 长时间内系统的准确质量数稳定, 且该系统的质量准确度小于1 mg/kg。结论 该方法满足对食品/农产品中农药残留的筛查检测要求, 适用于检测部门的日常筛查工作。     

Multiresidue analysis of pesticides in agricultural products by GC/MS coupled with database software

We evaluated a multiresidue method for determination of pesticides in agricultural products by SCAN mode GC/MS coupled with three kinds of database for 253 pesticides: relative retention time, mass spectra and calibration curve (SCAN method). Twenty-six pesticides, a total of 131 pesticides were detected in samples by the SCAN method. The detection results agreed closely with those of the SIM mode GC/MS method using calibration standards (SIM method). The ratios of the SCAN method to the SIM method ranged from 0.3 to 3.1 with SD values of 0.63. It was judged that the SCAN method could be applied to the screening analysis of pesticide residues in agricultural products, provided that the sample preparation method makes it possible to effectively remove sample matrixes with minimal loss of analytes.     

Simultaneous determination of pesticides in agricultural products by LC/MS/MS using clean-up with ultrafiltration

A method for simultaneous determination of multiple pesticide residues in agricultural products was developed by using a pretreatment with ultrafiltration, followed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The pretreatment process (extraction of pesticides from agricultural products with methanol, dilution of the extract with water, and ultrafiltration) gave recoveries in the range of 50-150% for 63 of 83 pesticides spiked at 0.25 microg/ g into 6 agricultural products. The detection limits of pesticides by LC/MS/MS were below 0.0005-0.05 micro/g. This method is useful for screening purposes and for multiresidue analysis of pesticides in agricultural products. Pesticide residues in 50 domestic crops were investigated by this method, and residues of 14 pesticides were detected in 30 crops.     

Feasibility of LC/TOFMS and elemental database searching as a spectral library for pesticides in food

Traditionally, the screening of unknown pesticides in food has been accomplished by GC/MS methods using conventional library-searching routines. However, many of the new polar and thermally labile pesticides are more readily and easily analysed by LC/MS methods and no searchable libraries currently exist (with the exception of some user libraries, which are limited). Therefore, there is a need for LC/MS libraries that can detect pesticides and their degradation products. This paper reports an identification scheme using a combination of LC/MS time-of-flight (accurate mass) and an Access database of 350 pesticides that are amenable to positive ion electrospray. The approach differs from conventional library searching of fragment ions. The concept consists of three parts: (1) initial screening of possible pesticides in actual market-place fruit extracts (apple and orange) using accurate mass and generating an accurate mass via an automatic ion-extraction routine, (2) searching the Access database manually for screening identification of a pesticide, and (3) identification of the suspected compound by accurate mass of at least one fragment ion and comparison of retention time with an actual standard. Imazalil and iprodione were identified in apples and thiabendazole in oranges using this database approach.     

Simultaneous determination of N-methylcarbamate and urea pesticides in agricultural products by LC/MS

A simultaneous determination method of 7 N-methylcarbamate and 7 urea pesticides in agricultural products by liquid chromatography/mass spectrometry (LC/MS) has been developed. Under reversed-phase liquid chromatographic conditions, 14 pesticides were analyzed using electrospray ionization (ESI) with simultaneous acquisition of positive ions and negative ions. Fourteen pesticides were extracted with acetone, 10% NaCl solution was added, and the pesticides were re-extracted with dichloromethane. The extract was concentrated under reduced pressure, and dissolved in methanol. The detection limits of 14 pesticides ranged from 0.0012 to 0.0056 microgram/g. The recoveries of pesticides were from 36.5 to 112.5% [RSD (n = 3) ranged from 0.5 to 48.1%] for 4 agricultural products.     

Determination of low-level pesticide residues in agricultural products by ion-trap GC/MS/MS

The objective of this study was to elucidate the utility of ion-trap GC/MS/MS for the analysis of pesticides in extracted matrices from various agricultural products. Identification and quantitative analysis of pesticides in matrices were performed by quadrupole GC/MS and ion-trap GC/MS/MS. Chlorpyrifos was added to the matrix of spinach, soybean in the pod or corn, and aldrin, dieldrin, endrin, alpha-BHC, beta-BHC, gamma-BHC, delta-BHC, p,p'-DDD, p,p'-DDE, o,p'-DDT and p,p'-DDT were added to each matrix of green tea, black tea or oolong tea. Although most of the pesticides in the matrix could not be determined by quadrupole GC/MS-Scan analysis at 0.1 microgram/mL, every pesticide was identified from the mass spectrum using ion-trap GC/MS/MS at the same concentration. The quantitation limit of every pesticide in each matrix by ion-trap GC/MS/MS analysis was higher than that by GC/MS-SIM analysis. The calibration curves obtained by GC/MS/MS were linear in the range of 0.01-0.25 microgram/mL of each pesticide. The recoveries of each pesticide from four kinds of samples spiked at the levels of 0.01 ppm to 0.02 ppm in extracts were 61.2-138.3% with SD values in the range from 1.2 to 15.4%. This study revealed that ion-trap GC/MS/MS was useful for the identification and quantitative analysis of low-level pesticides residues in matrices of agricultural products.     

Marine-derived bioactive materials for neuroprotection

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of 56 residual pesticides from commercial crops. For a validation of the method, the recoveries, linearities, limits of detection (LOD), and limits of quantitation (LOQ) of the 56 pesticides were investigated. The linearities, LOD, and mean recoveries of the pesticides ranged 0.9686–0.9999, 0.00–11.54 μg/kg, and 65–82%, respectively. This method was evaluated by its application to monitor 345 agricultural products collected from 9 provinces in Korea 2011. Fifteen pesticides were detected from 39 samples and 2 or more residual pesticides were found in 7 samples. However, none of the compounds were observed above the corresponding maximum residue level. The results reflect that the detected pesticide residues were in a safe range and that residual pesticides in the agricultural products in Korea were properly controlled.     

Screening method for the determination of 199 pesticides in agricultural products by gas chromatography/ion trap mass spectrometry (GC/MS/MS)

A screening method is described for determining 200 pesticides, except dimethipin, divided into four groups by means of gas chromatography/tandem mass spectrometry (GC/MS/MS) using an ion trap mass spectrometer equipped with automated gain control (AGC). The quantitation limit for 194 pesticides was 0.01 mg/kg on a crop basis, except for allidochlor, dimethoate, hexythiazox, methamidophos and triadimenol. The calibration curve of each pesticide was linear in the range of 0.04-5.0 microg/mL. One hundred and ninety-nine pesticides were added to matrix of potato, spinach, cabbage, apple, orange, soybean and unpolished rice at twice the limits of quantitation. The recoveries of 194 pesticides from all crops were satisfactory (50-150%) for screening purposes. Although some pesticides in apple and orange were not determined by selected ion monitoring (SIM) analysis at the limits of quantitation, all of them were identified by ion-trap GC/MS/MS at the same concentration. Thus, the ion trap GC/MS/MS technique is useful for the screening of residual pesticides present at low levels in agricultural products.     

2019年上海市食用农产品监督抽检情况分析

对2019年上海市市场监管局对外发布的食用农产品监督抽检相关信息进行汇总分析。数据显示2019年度上海市市场监督管理局共完成省级食用农产品抽检任务6 039批次,合格率为99.2%,其中水果和畜禽肉及副产品的合格率高于总体水平。食用农产品整体安全质量状况较好。抽检中发现的主要问题为农兽药的违规使用和重金属污染,未来仍需进一步加强对食用农产品相关企业的监管力度。