气相色谱-三重四极杆质谱联用法检测市售腊肠中9种挥发性亚硝胺

采用QuEChERS方法对市售腊肠中的N-亚硝基二甲胺(NDMA)、N-亚硝基二乙胺(NDEA)、N-亚硝基甲乙胺(NMEA)、N-亚硝基二丙胺(NDPA)、N-亚硝基吡咯烷(NPYR)、N-亚硝基哌啶烷(NPIP)、N-亚硝基二丁胺(NDBA)、N-亚硝基吗啉(NMOR)、N-亚硝基二苯胺(NDPhA)9种对人体有致癌活性的挥发性亚硝胺进行分离净化,气相色谱-三重四极杆质谱联用法(GC-MS/MS)检测。最佳实验条件下,9种挥发性亚硝胺的线性范围为0.25~200μg/L,检出限为0.01~0.10μg/kg,加标回收率为90.7%~116.0%,相对标准偏差(RSD)为1.8%~14.0%。市售腊肠样品中NDMA,NMOR,NPYR,NDPA,NPIP,NDBA,NDPhA均有不同程度的检出,总挥发性亚硝胺的含量为1.85~13.44μg/kg。该方法灵敏度高、操作简单,适合批量样品的快速检测。     

GC-LRMS法测定啤酒中3种N-亚硝胺化合物

用气相色谱-低分辨率质谱(GC-LRMS)联用法测定了啤酒中的3种亚硝胺.通过与脱亚硝基化试剂(HBr+HAc)作用,脱去亚硝基生成相应的二级胺,再与对甲苯磺酰氯反应,然后进行GC-LRMS分析.与原N-亚硝胺化合物相比,有效地改善了N-亚硝胺的色谱行为,衍生化后目标化合物的检测限降低了1～2个数量级(低至0.05μg...     

固相萃取-气相色谱-串联质谱法测定牛奶中9种N-亚硝胺的含量

建立固相萃取-气相色谱-串联质谱法同时测定牛奶中9种N-亚硝胺的分析方法.在10.0 g牛奶样品中加入10 mL乙腈提取9种N-亚硝胺,Captiva EMR-Lipid固相萃取小柱净化提取液,低温微流氮吹浓缩净化液,气相色谱-串联质谱仪采用多反应监测(MRM)模式测定,内标法进行定量.9种N-亚硝胺的线性范围均为0....     

固相萃取-气相色谱-串联质谱法测定乳胶儿童用品中15种N-亚硝胺及其前体物的迁移量

建立了同时测定乳胶儿童用品中15种N-亚硝胺及其前体物迁移量的固相萃取-气相色谱-串联质谱(SPEGC-MS/MS)分析方法。以人工唾液作为迁移模拟物,以Chromabond Easy固相萃取柱(填料的主要成分是极性修饰的聚乙烯-二乙烯基苯共聚物)对迁移液中的N-亚硝胺分析物进行净化,采用HP-5 MS UI色谱柱分离,MS/MS在多反应监测模式下进行定性及定量分析。15种N-亚硝胺在5~2 000μg/L范围内呈良好的线性关系,相关系数均大于0.998;方法定量限(S/N=10)为0.625~12.50μg/kg,低于欧盟2 009/48/EC指令的限量要求。在低、中、高3个添加水平的回收率为53.8%~116.2%、52.7%~105.1%和49.5%~102.9%;日内精密度分别为1.3%~14.0%(n=6),日间精密度为1.6%~7.6%(n=4)。采用本方法对婴儿奶嘴样品和气球样品进行了测定,其中4件奶嘴和7件气球样品中检出亚硝胺及其前体物,奶嘴和气球中N-亚硝胺的总检出含量分别为0.049 9~0.126mg/kg和0.515~41.2 mg/kg;N-亚硝胺前体物总检出量分别为0.026 4~0.030 0 mg/kg和0.187~12.5mg/kg。     

气相色谱-质谱联用法测定腌制水产品中的挥发性N-亚硝胺类化合物

建立了气相色谱-质谱(GC-MS)快速测定腌制水产品中挥发性N-亚硝胺含量的分析方法。采用GC-MS测定了N-二甲基亚硝胺(NDMA)、N-二乙基亚硝胺(NDEA)、N-二丙基亚硝胺(NDPA)、N-亚硝基吡咯烷(NPYR)、N-亚硝基哌啶(NPIP)、N-二丁基亚硝胺(NDBA)6种化合物,考察了样品不同提取方法、不同固相萃取小柱、不同色谱柱对分离检测的影响。结果显示: 在10～1000 μg/L范围内,线性相关系数可达0.9998以上;重现性良好,相对标准偏差小于8%;回收率可达79%～105%;灵敏度高,检出限低,除NDPA为0.03 μg/kg外,其他5种N-亚硝胺为0.05 μg/kg。该方法前处理快速简捷,易于操作,适用于腌制水产品中N-亚硝胺残留量的检测工作。     

气相色谱-热能分析仪测定汽车内饰件中9种N-亚硝胺散发量

建立了气相色谱-热能分析(GC-TEA)同时测定汽车内饰件中9种N-亚硝胺散发量的方法.使用1 m3环境舱对样品进行加热处理,Thermosorb N亚硝胺专用采样管进行气体采集,二氯甲烷/甲醇溶液对采样管进行洗脱后,样品溶液使用GC-TEA进行N-亚硝胺的测定,外标法定量.结果 表明:9种N-亚硝胺在7～500 ng...     

改进的QuEChERS结合气相色谱-三重四极杆质谱法快速测定酸肉中10种挥发性N-亚硝胺类化合物

采用改进的QuEChERS方法进行提取和净化,建立了气相色谱-三重四极杆质谱(GC-MS/MS)快速测定酸肉样品中10种挥发性N-亚硝胺类化合物的检测方法。样品经乙腈提取和正己烷除脂后,采用十八烷基硅烷键合硅胶(C18)和N-丙基乙二胺(PSA)混合吸附剂净化,采用DB-WAX色谱柱(30 m×0.25 mm×0.25μm)分离,在选择反应监测(SRM)模式下进行测定,外标法定量。10种N-亚硝胺类化合物在1~100μg/L范围内线性关系良好,相关系数(r)均0.99。10种N-亚硝胺类化合物的加标回收率为79.8%~115.3%,相对标准偏差(RSD)为0.6%~22.9%(n=6);方法的检出限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.04~0.3μg/kg和0.1~1μg/kg。该法简便快速,灵敏有效,适用于酸肉中N-亚硝胺类化合物的快速筛查和测定。     

乳胶制品中N-亚硝胺析出物的GC-MS/SIM检测

使用气相色谱-质谱(GC-MS/SIM)检测了乳胶制品中5种N-亚硝胺析出物,样品经过二氯甲烷萃取,用Rtx-5MS石英毛细管柱分离,采用内标法进行检测计算.实验得出5种N-亚硝基化合物的内标标准曲线日内RSD(小于5%),日间RSD(小于14%).N-亚硝基二乙胺(NDEA)、N-亚硝基二丙胺(NDPA)、N-亚硝基哌啶(NPIP)、N-亚硝基二丁胺(NDBA)、N-亚硝基二苯胺(NDPhA)的方法的检出限分别为2.0,5.0,10.0,1.0,112.0μg/L.运用该法对北京市场的乳胶制品进行了检测.     

超高效液相色谱-三重四极杆质谱联用仪同时检测水中9种亚硝胺

采用超高效液相色谱-三重四极杆质谱联用仪(UPLC-MS/MS)优化了9种亚硝胺的质谱运行参数,并通过对比不同流动相、固相萃取柱和定容溶剂对水中9种亚硝胺检测强度的影响,确定以甲醇-10 mmol/L碳酸氢铵溶液为流动相,使用椰壳活性炭萃取柱对样品进行预处理,超纯水作为定容溶剂。在最优实验条件下,9种亚硝胺的线性范围为5~150 ng/L,相关系数(r2)为0.997~0.999,检出限和定量下限分别为1.3~2.8 ng/L和4.0~8.5 ng/L;日内(n=5)和日间(n=6)相对标准偏差分别为3.5%~8.4%和2.8%~7.5%。3种不同实际水样在25 ng/L和100 ng/L加标浓度水平下,回收率达80.4%~109.6%。使用该方法对6个不同给水处理厂和污水处理厂出水中的亚硝胺浓度进行检测,其中N-亚硝基二甲胺(NDMA)的检测浓度最高,分别为10.2 ng/L和45.6 ng/L。     

双填料固相萃取-高效液相色谱/质谱法同时检测腌菜中9种N-亚硝胺

亚硝胺是三大强致癌食品污染物之一,普遍存在于腌制和热加工食品中。本研究建立了一种基于液质联用技术结合多级反应监测模式扫描(MRM)检测N-亚硝胺的新型固相萃取-液相色谱方法,可以快速直接检测腌菜中9种N-亚硝胺。实验优化了液相色谱分离与检测条件,同时考察了4种固相萃取单柱(碱性氧化铝Al2O3、C18、硅胶、硅藻土)和2种双填料的混合固相萃取柱(Al2O3-C18,Al2O3-硅胶)吸附解析的净化效果。结果表明,采用Al2O3-C18混合柱纯化,液相色谱检测,外标法定量,对9种亚硝胺的回收率达75.7%～116.0%,检出限为0.20～0.49 mg/L。采用本方法检测不同产地的6类腌菜产品中亚硝胺含量,二甲基亚硝胺和二乙基亚硝胺的检出率相对较高,分别为37.5%和25.0%,其中二乙基亚硝胺在雪里蕻腌菜中最高含量达59.1 mg/L,亚硝基吗啉在所有样品中未检出。     

Determination of eight nitrosamines in water at the ng L(-1) levels by liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry

In this work, we have developed a sensitive method for detection and quantification of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMor), N-nitrosomethylethylamine (NMEA), N-nitrosopirrolidine (NPyr), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPip), N-nitroso-n-dipropylamine (NDPA) and N-nitrosodi-n-butylamine (NDBA) in drinking water. The method is based on liquid chromatography coupled to tandem mass spectrometry, using atmospheric pressure chemical ionization (APCI) in positive mode with a triple quadrupole analyzer (QqQ). The simultaneous acquisition of two MS/MS transitions in selected reaction monitoring mode (SRM) for each compound, together with the evaluation of their relative intensity, allowed the simultaneous quantification and reliable identification in water at ppt levels. Empirical formula of the product ions selected was confirmed by UHPLC-(Q)TOF MS accurate mass measurements from reference standards. Prior to LC-MS/MS QqQ analysis, a preconcentration step by off-line SPE using coconut charcoal EPA 521 cartridges (by passing 500 mL of water sample) was necessary to improve the sensitivity and to meet regulation requirements. For accurate quantification, two isotope labelled nitrosamines (NDMA-d(6) and NDPA-d(14)) were added as surrogate internal standards to the samples. The optimized method was validated at two concentration levels (10 and 100 ng L(-1)) in drinking water samples, obtaining satisfactory recoveries (between 90 and 120%) and precision (RSD<20%). Limits of detection were found to be in the range of 1-8 ng L(-1). The described methodology has been applied to different types of water samples: chlorinated from drinking water and wastewater treatment plants (DWTP and WWTP, respectively), wastewaters subjected to ozonation and tap waters.     

固相萃取-大体积程序升温进样气相色谱-三重四极杆串联质谱测定饮用水中3种挥发性N-亚硝胺

建立了固相萃取大体积程序升温进样气相色谱-三重四极杆质谱联用（GC-QqQ-MS/MS）同时测定饮用水中N-亚硝基二甲胺、N-亚硝基甲基乙基胺及N-亚硝基二乙基胺的分析方法。用椰壳活性炭固相萃取小柱萃取水样中待测物组分，少量二氯甲烷洗脱、无水硫酸钠脱水，大体积程序升温进样，气相色谱-三重四极杆质谱联用仪进行多反应监测（MRM）模式检测，外标法定量。3种N-亚硝胺在1~50 ng/L范围内线性关系良好，相关系数（r²）均大于0.999，在饮用水中进行10、20和50 ng/L水平的添加，3种待测物平均加标回收率为94.8%~109%，相对标准偏差（RSD）为4.44%~8.10%（n=5），定量限（LOQ）为0.08~0.7 ng/L。该法灵敏、准确、简单、可靠，适用于饮用水中3种N-亚硝胺组分的痕量检测。     

Determination of eight nitrosamines in water at the ng L levels by liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry

In this work, we have developed a sensitive method for detection and quantification of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMor), N-nitrosomethylethylamine (NMEA), N-nitrosopirrolidine (NPyr), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPip), N-nitroso-n-dipropylamine (NDPA) and N-nitrosodi-n-butylamine (NDBA) in drinking water. The method is based on liquid chromatography coupled to tandem mass spectrometry, using atmospheric pressure chemical ionization (APCI) in positive mode with a triple quadrupole analyzer (QqQ). The simultaneous acquisition of two MS/MS transitions in selected reaction monitoring mode (SRM) for each compound, together with the evaluation of their relative intensity, allowed the simultaneous quantification and reliable identification in water at ppt levels. Empirical formula of the product ions selected was confirmed by UHPLC-(Q)TOF MS accurate mass measurements from reference standards.Prior to LC–MS/MS QqQ analysis, a preconcentration step by off-line SPE using coconut charcoal EPA 521 cartridges (by passing 500 mL of water sample) was necessary to improve the sensitivity and to meet regulation requirements. For accurate quantification, two isotope labelled nitrosamines (NDMA-d₆ and NDPA-d₁₄) were added as surrogate internal standards to the samples.The optimized method was validated at two concentration levels (10 and 100 ng L⁻¹) in drinking water samples, obtaining satisfactory recoveries (between 90 and 120%) and precision (RSD < 20%). Limits of detection were found to be in the range of 1–8 ng L⁻¹. The described methodology has been applied to different types of water samples: chlorinated from drinking water and wastewater treatment plants (DWTP and WWTP, respectively), wastewaters subjected to ozonation and tap waters.     

Analysis of nitrosamines in water by automated SPE and isotope dilution GC/HRMS Occurrence in the different steps of a drinking water treatment plant, and in chlorinated samples from a reservoir and a sewage treatment plant effluent

A method based on automated solid-phase extraction (SPE) and isotope dilution gas chromatography/high resolution mass spectrometry (GC/HRMS) has been developed for the analysis of nine nitrosamines in water samples. The combination of automated SPE and GC/HRMS for the analysis of nitrosamines has not been reported previously. The method shows as advantages the selectivity and sensitivity of GC/HRMS analysis and the high efficiency of automated SPE with coconut charcoal EPA 521 cartridges. Low method detection limits (MDLs) were achieved, along with a greater facility of the procedure and less dependance on the operator with regard to the methods based on manual SPE. Quality requirements for isotope dilution-based methods were accomplished for most analysed nitrosamines, regarding to trueness (80–120%), method precision (<15%) and MDLs (0.08–1.7 ng/L).Nineteen water samples (16 samples from a drinking water treatment plant {DWTP}, 2 chlorinated samples from a sewage treatment plant {STP} effluent, and 1 chlorinated sample from a reservoir) were analysed. Concentrations of nitrosamines in the STP effluent were 309.4 and 730.2 ng/L, being higher when higher doses of chlorine were applied. N-Nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were the main compounds identified in the STP effluent, and NDEA was detected above 200 ng/L, regulatory level for NDMA in effluents stated in Ontario (Canada). Lower concentrations of nitrosamines were found in the reservoir (20.3 ng/L) and in the DWTP samples (n.d. −28.6 ng/L). NDMA and NDEA were respectively found in the reservoir and in treated and highly chlorinated DWTP samples at concentrations above 10 ng/L (guide value established in different countries). The highest concentrations of nitrosamines were found after chlorination and ozonation processes (ozonated, treated and highly chlorinated water) in DWTP samples.     

Solid-phase extraction and high-performance liquid chromatography mass spectrometry analysis of nitrosamines in treated drinking water and wastewater

N-Nitrosamines, including N-nitrosodimethylamine (NDMA), were identified as chlorination byproducts in drinking water in 1989. Nitrosamines are known rodent carcinogens and probable human carcinogens, and so they are considered disinfection byproducts (DBPs) of public health concern. Epidemiological studies show a potential association of consumption of chlorinated drinking water with an increased risk of bladder cancer. As small, relatively polar DBPs that often occur at low-ng/L concentrations in water, nitrosamines pose analytical challenges for accurate determination. Sample preparation (e.g., the commonly used solid-phase extraction) plays a critical role in achieving reliable determination of nitrosamines at ng/L concentrations. Historically, gas chromatography (GC)-based techniques have been used for nitrosamine analysis. Recently, newly developed liquid chromatography–tandem mass spectrometry (LC-MS²) methods have shown potential advantages in determining polar DBPs. This review focuses on the sample preconcentration methods and LC-MS² determination of nitrosamines in drinking water and wastewater. It also provides a historical perspective on nitrosamines and their occurrence in drinking water.     

Nitrogen-phosphorus detection and nitrogen chemiluminescence detection of volatile nitrosamines in water matrices: optimization and performance comparison

Two nitrogen-specific detection methods, nitrogen-phosphorus detection (NPD) and nitrogen chemiluminescence detection (NCD), were investigated as low cost alternatives to mass spectrometry (MS) with chemical ionization (CI) for analysis of nitrosamines in aqueous samples. NCD showed greater sensitivity to N-nitrosodimethylamine (NDMA) and seven other volatile nitrosamines than did NPD. Instrument detection levels for NDMA were established at 2.6 microg/L and 4.0 microg/L in solvent with 3 microL splitless gas chromatograph (GC) injection for NCD and NPD, respectively. Using a dual-column confirmation method, both NCD and NPD compared favorably with CI-MS results for NDMA analysis in a variety of water sample types. For seven other nitrosamines, both detectors showed excellent accuracy in analyzing high concentrations (greater than 300 ng/L) in complex wastewater matrices, while the accuracy of spike recoveries of very low levels (less than 15 ng/L) in clean matrices varied for each nitrosamine and detection method.     

气相色谱-串联质谱法测定肉制品中10种挥发性N-亚硝胺类化合物

建立了气相色谱-串联质谱（GC-MS/MS）检测肉制品中10种挥发性N-亚硝胺类化合物残留量的方法。肉制品样品经同时蒸馏萃取法（SDE）萃取，采用冷冻去脂净化法，在多反应监测模式下分析，外标法定量。结果表明，采用优化后的条件，10种挥发性N-亚硝胺类化合物在1.00~1000 μg/L范围内线性关系良好，相关系数均在0.99以上。方法的检出限（LOD，S/N=3）和定量限（LOQ，S/N=10）分别为0.01~0.02 μg/kg和0.04~0.07 μg/kg。选取3种不同类型的肉制品（火腿肠、中式香肠和腌渍腊肉），在空白样品添加水平为LOQ水平、1.0、2.0 μg/kg时，10种挥发性N-亚硝胺类化合物的平均回收率为74.8%~94.3%，相对标准偏差小于8.3%。市售3类肉制品中6种挥发性N-亚硝胺类化合物（N-亚硝基二甲胺、N-亚硝基二乙胺、N-亚硝基吡咯烷、N-亚硝基哌啶、N-亚硝基二丁胺、N-亚硝基二丙胺）均有不同程度检出，且腌渍腊肉中每种挥发性N-亚硝胺类化合物的检出值最高。该方法操作简单，萃取充分，灵敏度高，试剂用量少，可满足实验室大量样品的日常检测需求。     

Method development for the analysis of N-nitrosodimethylamine and other N-nitrosamines in drinking water at low nanogram/liter concentrations using solid-phase extraction and gas chromatography with chemical ionization tandem mass spectrometry

N-nitrosodimethylamine (NDMA) is a probable human carcinogen of concern that has been identified as a drinking water contaminant. U.S. Environmental Protection Agency Method 521 has been developed for the analysis of NDMA and 6 additional N-nitrosamines in drinking water at low ng/L concentrations. The method uses solid-phase extraction with coconut charcoal as the sorbent and dichloromethane as the eluent to concentrate 0.50 L water samples to 1 mL. The extracts are analyzed by gas chromatography-chemical ionization tandem mass spectrometry using large-volume injection. Method performance was evaluated in 2 laboratories. Typical analyte recoveries of 87-104% were demonstrated for fortified reagent water samples, and recoveries of 77-106% were demonstrated for fortified drinking water samples. All relative standard deviations on replicate analyses were < 11%.     

N-Nitrosodimethylamine Contamination in the Metformin Finished Products

A GC–MS/MS method with EI ionization was developed and validated to detect and quantify N-nitrosodimethylamine (NDMA) and seven other nitrosamines in 105 samples of metformin tablets from 13 different manufactures. Good linearity for each compound was demonstrated over the calibration range of 0.5–9.5 ng/mL. The assay for all substances was accurate and precise. NDMA was not detected in the acquired active pharmaceutical ingredient (API); however, NDMA was detected in 64 (85.3%) and 22 (91.7%) of the finished product and prolonged finished product samples, respectively. European Medicines Agency recommends the maximum allowed limit of 0.032 ppm in the metformin products. Hence, 28 finished products and 7 pronged dosage products were found to exceed the acceptable limit of daily intake of NDMA contamination. The implications of our findings for the testing of pharmaceutical products are discussed.     

Analysis of bromate in drinking water using liquid chromatography-tandem mass spectrometry without sample pretreatment

An analytical method for determining bromate in drinking water was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The (18)O-enriched bromate was used as an internal standard. The limit of quantification (LOQ) of bromate was 0.2 μg/L. The peak of bromate was separated from those of coexisting ions (i.e., chloride, nitrate and sulfate). The relative and absolute recoveries of bromate in two drinking water samples and in a synthesized ion solution (100 mg/L chloride, 10 mg N/L nitrate, and 100 mg/L sulfate) were 99-105 and 94-105%, respectively. Bromate concentrations in 11 drinking water samples determined by LC-MS/MS were <0.2-2.3 μg/L. The results of the present study indicated that the proposed method was suitable for determining bromate concentrations in drinking water without sample pretreatment.