气相色谱-串联质谱法测定食品中的三聚氰胺

建立了使用气相色谱-串联质谱(GC-MS/MS)测定食品中三聚氰胺含量的分析方法。利用三氯乙酸超声萃取样品中的三聚氰胺,经乙酸锌溶液沉淀蛋白质后,将提取液离心、过滤、净化、衍生后采用GC-MS/MS的多反应监测模式（MRM）进行检测。方法的重现性良好,6次重复测定的峰面积的相对标准偏差小于9%;最低定量检测限（S/N=10）为1 μg/kg,在0.1~100 μg/L范围内具有良好的线性关系。应用所建立的方法测定了奶粉、奶糖、含乳饮料、饼干等食品中的三聚氰胺含量,为三聚氰胺滥用的检测和判断提供了方法。     

LC-MS/MS内标法测定水产品中三聚氰胺残留量

建立了高效液相色谱-电喷雾串联质谱(LC-MS/MS)测定水产品中残留的三聚氰胺的方法.以13C,15N标记三聚氰胺为内标,样品经三氯乙酸溶液沉淀蛋白,提取目标分析物,经SCX-C18均匀混合填装的反相色谱柱分离,选择反应监测(SRM)正离子模式测定.LC-MS/MS的检测低限为10 μg/kg;在10.0～500 ng/mL时峰强度与质量浓度的线性关系良好(r>0.99).方法的平均回收率为78%～118%.     

鸡肉中11种喹诺酮类药物多残留的高效液相色谱检测

建立了用荧光检测器同时测定11种喹诺酮类药物(包括诺氟沙星、培氟沙星、环丙沙星、恩诺沙星、氧氟沙星、达氟沙星、洛美沙星、二氟沙星、沙拉沙星、恶喹酸和氟甲喹)在鸡肉中的多残留的高效液相色谱检测方法。鸡肉样品用10%三氯乙酸-乙腈(体积比为7∶3)提取两次并稀释,随后用反相固相萃取柱净化。采用Hypersil BDS-C18色谱柱分离,以乙腈和水为流动相梯度洗脱,荧光检测器用程序编程检测波长检测。11种喹诺酮类药物标准曲线的线性范围为5～1200 μg/L,相关系数大于0.998。在高、中、低三个添加水平下的回收率为56%～119%,批内相对标准偏差为0.4%～16.1%,批间相对标准偏差为1.4%～23.0%。检出限和定量限分别为1～23 μg/kg和4～40 μg/kg。该方法快速、灵敏,达到了兽药残留检测的要求。     

气相色谱-质谱法测定鸡肉组织中残留的氯羟吡啶

建立了气相色谱-质谱(GC-MS)测定鸡肉组织中氯羟吡啶残留的确证方法。采用乙腈提取鸡肉组织中的待测物,经碱性氧化铝层析柱净化,Sylon BFT衍生剂衍生后,采用选择离子监测(SIM)模式检测。对氯羟吡啶三甲基硅烷化衍生物的电子轰击（EI）质谱碎片进行解析,选择m/z 212,214,248和263等4个特征离子作为定性离子,其中m/z 248为定量离子。同时还考察了检测过程中的基质效应。氯羟吡啶衍生物的响应与其质量浓度在5.0～500 μg/L范围内呈良好的线性关系,相关系数大于0.998;以3倍信噪比(S/N)计算方法的检出限达0.5 μg/kg;在5,10和20 μg/kg添加水平下鸡肉组织中待测物的平均回收率分别为77.0%,84.5%及89.4%,相对标准偏差小于6.9%。结果表明,该方法简单、灵敏、可靠,适用于鸡肉组织中氯羟吡啶残留的分析确证。     

气相色谱-串联质谱法测定贝类中指示性多氯联苯

研究并建立了测定贝类中多氯联苯残留的气相色谱-串联质谱(GC-MS/MS)方法.通过正己烷和丙酮的混合溶液超声提取,硅胶柱净化,旋转蒸发浓缩,采用GC-MS/MS多反应监测(MRM)方式测定,可同时对贝类中的7种指示性多氯联苯进行定性和定量.研究结果表明:7种指示性多氯联苯的检出限(S/N=3)为0.0066～0.0098μg/kg,定量限(S/N=10)为0.02 μg/kg;在0.1～50.0 ng/mL时峰强度与质量浓度的线性关系良好(r>0.99).方法的平均回收率为73%～113%.该法简便快捷,降低了分析成本,在一定程度上实现了持久性污染物的快速检测和确证.     

高效液相色谱-串联质谱法测定猪肉中泰拉霉素残留

建立了高效液相色谱-串联质谱(HPLC-MS/MS)测定猪肉样品中新型兽药泰拉霉素残留的方法.样品用V(甲醇): V(0.1% H3PO4)=70: 30混合溶液提取,经离心后用PCX固相萃取小柱净化, 以SymmetryC8色谱柱为分离柱,在串联质谱多反应监测(MRM)模式下检测,内标法定量.方法的线性范围为10～500 μg/kg,检出限为5.0 μg/kg,在3个浓度水平(10,20和50 μg/kg)进行添加实验,平均回收率为93.1%～105.5%; 批内相对标准偏差为1.5%～4.6%; 批间相对标准偏差为1.8 %～5.6%.     

气相色谱-串联质谱法同时测定三七中212种农药残留

建立了气相色谱-串联质谱(GC-MS/MS)同时测定三七中212种农药残留的方法。样品以乙腈-乙酸乙酯(体积比1∶3)提取,经FaPEx-BKT50固相萃取柱净化,待测物采用GC-MS/MS测定,以保留时间和特征离子对定性,外标法定量。结果表明,212种农药在10～200μg/L范围内线性关系良好,相关系数(r²)均大于0.999,检出限(S/N=3)为0.003～0.02 mg/kg,定量下限(S/N=10)为0.01～0.05 mg/kg。在空白样品中进行0.02、0.04、0.1 mg/kg 3个水平的加标回收实验,212种农药的平均回收率为60.0%～121%,相对标准偏差(RSD)为0.90%～31%。该方法简单、灵敏、稳定,可有效去除复杂基体的干扰,各项技术指标均满足国内外农药残留的限量要求,适用于中药材三七中痕量农药的残留测定。     

QuEChERS/GC-MS/MS测定人参中41种农药残留

建立了QuEChERS结合气相色谱-串联质谱(GC-MS/MS)测定人参中41种农药残留的分析方法,采用选择反应监测(SRM)模式,外标法定量,并考察了Original、Acetate和Citrate 3种QuEChERS前处理方法对人参基质中目标农药的提取效率和净化效果。结果表明,采用Original QuEChERS前处理方法时,41种农药在一定浓度范围内的线性良好,相关系数(r)大于0.995,方法的检出限(LOD,S/N=3)为2.0～6.0μg/kg,定量下限(LOQ,S/N=10)为5.0～20.0μg/kg。在10、20、100、200μg/kg 4个加标水平下的回收率为86.7%～115%,相对标准偏差(RSD)均小于15%。该方法样品前处理简单、高效、准确、灵敏,适用于人参中多农药残留的筛选与测定。     

气相色谱-质谱法测定水产品中15种邻苯二甲酸酯类塑化剂的残留量

建立了同时测定水产品中15种邻苯二甲酸酯类塑化剂残留的气相色谱-质谱(GC-MS)分析方法。样品经二氯甲烷-正己烷(1∶1)混合溶液超声萃取,中性氧化铝玻璃层析柱净化,用正己烷、二氯甲烷-正己烷(1∶9)混合液、乙酸乙酯-正己烷(1∶4)混合液和乙酸乙酯依次洗脱目标物,洗脱液经浓缩后正己烷定容,气相色谱-质谱测定。结果显示,15种邻苯二甲酸酯的线性范围为0.05～1.0 mg/L,相关系数(r)不小于0.999 1,检出限(LOD,S/N=3)为0.04～1.18μg/kg,定量下限(LOQ,S/N=10)为0.20～4.00μg/kg,不同水产品样品中添加2、50、200μg/kg的15种PAEs,平均加标回收率为81%～123%,相对标准偏差(RSDs,n=3)均小于15%。该方法稳定、可靠、操作简便,适用于鱼肉等水产品中多种PAEs的同时检测与确证。     

加速溶剂萃取/GC-MS法对辐照肉类食品中2-十二烷基环丁酮的检测

应用加速溶剂萃取(ASE)/气相色谱-质谱(GC-MS)技术建立了辐照肉类食品中2-十二烷基环丁酮(2-DCB)的检测方法.采用加速溶剂萃取法从辐照过的肉类样品中提脂,萃取液加入乙腈后冰箱冷冻去除脂肪,LC-Si固相萃取小柱净化,氮气吹干后加入内标定容,于GC-MS仪上测定,在0.1 ～0.4 μg/g(以脂肪计)范围内的回收率为78% ～92%,RSD小于11%,定量下限为0.1 μg/g(以脂肪计).同时采用该方法对辐照剂量为1 ～8 kGy的猪肉、鸡肉和鱼肉进行检测,再次证明了辐照剂量与脂肪中2-DCB含量存在线性相关关系.     

Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with pressurized liquid extraction for simultaneous quantification and confirmation of cyromazine, melamine and its metabolites in foods of animal origin

Simple and sensitive methods have been developed for simultaneous detection of cyromazine, melamine and their metabolites (ammeline, ammelide and cyanuric acid) in samples of animal origins. These include a high performance liquid chromatography (HPLC) method and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and are useful in regular monitoring and in toxicity studies of these molecules. Representative samples used in this study include muscles and livers of swine, bovine, sheep and chicken, kidneys of swine, bovine and sheep, and milk powder. A new sample preparation procedure with pressurized liquid extraction (PLE) at 1400psi and 70°C was investigated. Quantification of these five compounds by HPLC was achieved using an APS-2 column with UV detection at 230 nm. Limit of detection (LOD) was at 10 μgkg(-1), and limit of quantification (LOQ) was at 40 μgkg(-1). Recoveries of the five analytes in spiked samples ranged from 72.2% to 115.4% with RSD less than 12%. Confirmatory analysis of the analytes was performed using LC-MS/MS in selected reaction monitoring (SRM) mode. The LOD and LOQ were 5 μgkg(-1) and 15 μgkg(-1), respectively. This is the first simultaneous analysis of cyromazine, melamine, ammeline, ammelide and cyanuric acid residues in complex tissue samples using PLE and HPLC. It is expected that these methods will find many practical applications in evaluating the safety of cyromazine, melamine and their metabolites.     

气相色谱-质谱/质谱法检测蔬菜中的毒死蜱及其代谢物

建立了蔬菜中毒死蜱及其代谢物3,5,6-三氯-2-羟基吡啶（3,5,6-trichloro-2-pyridinol,TCP)的气相色谱-质谱/质谱分析方法。蔬菜样品采用丙酮提取,浓缩后TCP用N-甲基-N-叔丁基二甲基硅基三氟乙酰胺(MTBSTFA)衍生,再经氟罗里硅土固相萃取柱净化。采用三重四极杆质谱电子轰击多反应监测(MRM)模式测定。采用内标法对毒死蜱定量,方法的检出限为1 μg/kg,加标回收率为75.57%～106.41%,相对标准偏差(RSD)为8.33%～17.58%。采用外标法对TCP定量,方法的检出限为0.5 μg/kg,加标回收率为69.11%～108.43%,RSD为5.20%～19.42%。在2～100 μg/L范围内,两种被测物的线性关系良好（r＞0.99）。该方法可用于蔬菜中毒死蜱及其代谢物的检测。     

Preparation of a magnetic molecularly imprinted polymer with pseudo template for rapid simultaneous determination of cyromazine and melamine in bio-matrix samples

A magnetic molecularly imprinted polymer (M-MIP) for cyromazine and melamine was prepared by simple suspension polymerization using a pseudo template, 2-(4,6-diamino-1,3,5-triazin-2-ylamino)ethanethiol disulfide. The M-MIP was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and vibrating sample magnetometry. Molecular recognition properties and binding capability to cyromazine and melamine were evaluated by adsorption testing, which showed the M-MIP had better affinity and selectivity than the magnetic non-imprinted polymer (M-NIP) for cyromazine and melamine. A method based on molecularly imprinted solid-phase extraction assisted by magnetic separation was developed for extraction of cyromazine and melamine from bio-matrix samples. Various conditions, for example desorption conditions, amount of M-MIP, extraction time, and sample pH were optimized. High-performance liquid chromatography with UV detection was used to determine cyromazine and melamine after extraction. The proposed method was successfully applied to determination of cyromazine and melamine in egg and milk samples. Recovery of standard spiked cyromazine and melamine from these samples was between 71.86 and 80.57%, with intraday and interday relative standard deviation ranging from 3.45 to 6.39% and from 3.95 to 7.84%, respectively. The results indicate that the pseudo template M-MIP can be used for preconcentration, purification, and analysis of cyromazine and melamine in bio-matrix samples.     

Residue determination of cyromazine and its metabolite melamine in chard samples by ion-pair liquid chromatography coupled to electrospray tandem mass spectrometry

A method has been developed for the sensitive and selective determination of cyromazine and its metabolite melamine in chard samples. Both compounds are small polar basic molecules, making their determination at residue levels complicated. The method involves an extraction procedure with phosphate buffer and methanol using high-speed blender, the addition of tridecafluoroheptanoic acid (TFHA) as ion-pair reagent and the injection of the five-fold diluted extract on liquid chromatography coupled to electrospray tandem mass spectrometry (LC–ESI–MS/MS). The method has been validated for chard samples, spiked at 0.05 and 0.5 mg kg⁻¹. Quantification was carried out by using matrix-matched standards calibration and recoveries were satisfactory, with mean values for cyromazine of 103% and 93%, and relative standard deviations lower than 7%. In the case of melamine, recoveries were 89% and 86%, with relative standard deviations lower than 13%. A limit of quantification of 0.05 mg kg⁻¹ was obtained for both compounds, with the limit of detection below 0.01 mg kg⁻¹. The method, with very little sample handling and good sensitivity, was applied to the rapid determination of low residue levels of these compounds in chards from field residue trials. All the quality controls included during the analysis were satisfactory with average recoveries of 92% and 78% for cyromazine and melamine, respectively.     

Optimization of QuEChERS method for the analysis of organochlorine pesticides in soils with diverse organic matter

A QuEChERS method has been developed for the determination of 14 organochlorine pesticides in 14 soils from different Portuguese regions with wide range composition. The extracts were analysed by GC-ECD (where GC-ECD is gas chromatography-electron-capture detector) and confirmed by GC-MS/MS (where MS/MS is tandem mass spectrometry). The organic matter content is a key factor in the process efficiency. An optimization was carried out according to soils organic carbon level, divided in two groups: HS (organic carbon >2.3%) and LS (organic carbon <2.3%). The method was validated through linearity, recovery, precision and accuracy studies. The quantification was carried out using a matrix-matched calibration to minimize the existence of the matrix effect. Acceptable recoveries were obtained (70-120%) with a relative standard deviation of ≤16% for the three levels of contamination. The ranges of the limits of detection and of the limits of quantification in soils HS were from 3.42 to 23.77 μg kg(-1) and from 11.41 to 79.23 μg kg(-1), respectively. For LS soils, the limits of detection ranged from 6.11 to 14.78 μg kg(-1) and the limits of quantification from 20.37 to 49.27 μg kg(-1) . In the 14 collected soil samples only one showed a residue of dieldrin (45.36 μg kg(-1) ) above the limit of quantification. This methodology combines the advantages of QuEChERS, GC-ECD detection and GC-MS/MS confirmation producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.     

气相色谱-串联质谱法同时测定锂离子电池电解液中13种有机磷阻燃剂的含量

建立了一种可同时测定锂离子电池电解液中13种有机磷阻燃剂含量的气相色谱-串联质谱分析方法,以乙酸乙酯为萃取溶剂,超声萃取锂离子电池电解液中的有机磷阻燃剂,萃取液经浓缩、定容、过滤后进行气相色谱-串联质谱分析,外标法定量。结果显示,13种有机磷阻燃剂在一定浓度范围内线性良好,相关系数不低于0.999 3,方法的检出限(S/N=3)为0.3~30μg/kg,定量下限(S/N=10)为1~100μg/kg。在低、中、高3个加标水平下的平均回收率为80.4%~94.6%,相对标准偏差(RSD)为3.8%~10%。该方法简单快捷,灵敏度高,定量下限低,可满足锂离子电池电解液中有机磷阻燃剂含量日常检测需要。     

Fast quantitative determination of melamine and its derivatives by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

A simple, sensitive and fast method for the determination of melamine and its derivatives in milk powder using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was developed. Neither time-consuming sample preparation, nor special target plates, or other extra equipment are necessary. The common matrix sinapinic acid (SA) was used with a dried-droplet preparation. Detection limits (signal-to-noise (S/N) ratio = 3) for standard solutions of melamine, ammeline and cyanuric acid were 10, 25 and 10 μg/L, respectively. The limit of quantification (LOQ) for melamine was 25 μg/L and excellent linearity (R(2): 0.9990) was maintained over the range of 10-2000 μg/L. Ammeline and cyanuric acid were analyzed with an LOQ of 50 μg/L and also excellent linearity (R(2): 0.9997 and R(2): 0.9998). Good accuracy and precision were obtained for all concentrations within the range of the standard curve. The developed method was successfully used for the determination of melamine, ammeline and cyanuric acid in milk powder samples with a simple sample preparation. The LOQ of melamine was 0.5 μg/g. Ammeline and cyanuric acid were detectable at 0.5 and 5 μg/g. This method showed excellent accuracy, precision and linearity and significantly reduces the needed analysis time, as only approximately 10 s/sample measuring time is required. To the authors' knowledge, this is the first published method to quantify melamine and derivatives by MALDI-TOF-MS.     

分散固相萃取-气相色谱-串联质谱法测定蔬菜中107种农药的残留量

采用分散固相萃取-气相色谱-串联质谱(QuEChERS-GC-MS/MS)建立了蔬菜中107种农药残留量的分析方法。样品由含1%冰醋酸的正己烷饱和乙腈提取、分散固相萃取法净化,采用气相色谱-串联质谱方法在分时段选择反应监测模式下进行测定,外标法定量。所有农药在0.05～1 mg/L范围内线性关系均良好;所有农药的方法定量限(LOQ)均低于10 μg/kg;在10 μg/kg的添加水平下,大蒜、青刀豆、萝卜和菠菜4种基质中绝大多数农药的平均回收率处于60%～130%之间,相对标准偏差(RSD)不大于15.3%。该方法不仅能用于多种蔬菜基质中107种农药残留的检测,而且还能较好地解决本底成分相当复杂的大蒜基质极易出现的干扰问题。     

Determination of melamine residue in liquid milk by capillary electrophoresis with solid-phase extraction

A novel solid-phase extraction-capillary electrophoresis (SPE-CE) method was developed for the determination of melamine residue in liquid milk. The conditions of SPE and CE were investigated and optimized. A 1% trichloroacetic acid plus 2.2% lead acetate solution were used for the extraction of analyte and the removal of protein. A Cleanert PCX SPE cartridges column was used for clean up. The 50 mM sodium dihydrogenphosphate running buffer (pH adjusted to 3.2 with citric acid) was used as a running buffer. The linearity is satisfactory in the range of 0.8-100 μg/mL with a correlation coefficient of 0.9998. Under the optimal conditions, the method limit of detection (LOD) and method limit of quantification were 0.12 mg/kg and 0.37 mg/kg, respectively. The recovery of melamine from different liquid milk samples was in the range of 89.5-98.5% with a relative standard deviation of 1.8-3.5%. The intra- and inter-day assay precision was 2.8% (n = 6) and 4.1% for five days, respectively. The developed method has been applied successfully for the determination of melamine residue in liquid milk samples. The results obtained by the proposed method agree with those obtained by high-performance liquid chromatographic method. The proposed method enables the quantitative determination of melamine residues at levels as low as 0.37 mg/kg in different liquid milk.