液相色谱-四极杆飞行时间质谱法快速筛查与确证中华鳖中未知着色剂

建立了液相色谱-四极杆飞行时间质谱(LC-Q-TOF MS)对中华鳖中未知着色剂的快速筛查方法。20个中华鳖样品经过简易的乙腈提取净化后,利用液相色谱-二极管阵列检测器(LC-DAD)对未知着色剂进行定位。选定其中响应最强的样品S7,同时在线获取其在不同洗脱程序下未知着色剂定位时间段的质谱信息,经阴性样品扣除本底后匹配获得一对精确质量数差异在5 mDa以内的特征提取离子(分别为564.39773 Da和564.39561 Da)。通过质谱定性分析处理软件对上述特征提取离子对进行分子式生成,确认两者分子式为C₄₀H₅₂O₂,推测其同为未知着色剂。结合该未知着色剂的紫外-可见光谱信息与文献资料,推断该化合物可能为角黄素。通过角黄素标准品建立的飞行时间质谱"二级确证谱库"对样品中未知着色剂进行进一步的匹配确证,最终确证其为角黄素。本研究讨论了基于LC-Q-TOF MS方法的化合物筛查策略,实验表明其可快速对中华鳖中的未知着色剂进行筛查和确证。     

液相色谱-四极杆/飞行时间质谱快速筛查饲料中36种违禁药物

建立了饲料中β-受体激动剂、激素共36种违禁药物的液相色谱-四极杆/飞行时间质谱(LC-Q-TOF/MS)的快速筛查方法。均质饲料样品中加入乙腈和混合吸附剂,经涡旋分散、振荡提取、离心和浓缩步骤,实现了36种药物的同时提取和净化(改良的QuEChERS方法)。提取液以甲醇-0.1%甲酸为流动相进行梯度洗脱,C18色谱柱(150 mm×2.1 mm,2.7μm)分离,采用正离子模式检测分析。在100～1 000 Da质量范围内进行一级和二级质谱全扫描。以分子离子峰的精确质量数提取的色谱图峰面积定量,以二级质谱特征子离子和保留时间定性。36种药物的质量数误差绝对值小于7.3 ppm,在10.0～200.0μg/kg范围内线性关系良好,相关系数大于0.99。3个浓度水平的平均回收率为65%～120%,相对标准偏差不高于24%。该方法操作简便、结果准确,适用于饲料中违禁药物的高通量快速筛查分析。     

苯二氮卓类新精神活性物质Flubromazolam的快速检测

建立了气相色谱-质谱(GC-MS)和超高效液相色谱-串联四极杆飞行时间质谱(UPLC-Q-TOF MS)技术联合鉴定检材中flubromazolam的方法。未知样品用甲醇和水提取,取上清液,采用GC-MS和UPLC-Q-TOF MS进行分析。经GC-MS检测,保留时间为17.96 min的未知组分的质谱碎片主要特征离子峰有m/z 222,341,343,370,372,111,102,75。经UPLC-QTOF M S检测,保留时间为4.99 min的未知组分的准分子离子峰为m/z 371.0298,碰撞诱导解离(CID)模式下二级质谱主要离子有m/z 343.0114,302.9928,292.1118,263.0982,237.0951,223.0670。经美国缉毒署毒品分析谱库、缴获毒品分析科学工作组(SWGDRUG)分析谱库检索和文献查询获得的信息资料进行比对,确认目标物为flubromazolam。     

高效液相色谱-四极杆/飞行时间质谱鉴定阿莫西林克拉维酸钾干混悬剂中的未知组分

采用高效液相色谱-四极杆/飞行时间质谱(HPLC-QTOF/MS)建立了阿莫西林克拉维酸钾混悬剂(ACPS)中未知组分的鉴定方法,以BDS Hypersil C18(4.6 mm×250 mm,5μm)为色谱柱,以乙腈-水(0.1%甲酸)为流动相,流速为1 mL/min。比较了中国药典方法和HPLC-QTOF/MS方法的相关性;利用半制备液相色谱收集未知组分,并在HPLC-QTOF/MS体系中进行定位和确认,确定未知组分在液质体系中的出峰位置和准确分子量;筛查混合空白辅料成分,并通过与标准品比对,利用HPLC-QTOF/MS鉴定ACPS的未知组分为糖精钠。方法可为抗生素药品中未知组分的鉴定提供参考。     

基于质谱裂解机理的深加工羊肉制品中兽药残留非定向筛查技术研究

建立了一种基于质谱断裂机理的非定向筛查7类34种兽药残留的超高效液相色谱-四极杆-静电场轨道阱质谱(UHPLC-Q-Orbitrap MS)。采用数据非依赖采集模式进行质谱测定,基于标准化合物的保留时间、精确质量数、二级碎片离子信息进行定性筛选,通过解析分子离子的质谱碎裂过程与裂解机理,获得不同类别兽药的特征碎裂片段。结合特征离子,通过同位素离子峰信息与二级碎裂片段丰度比进行确证,构建非定向筛查方法。结果表明,34种兽药在各自的质量浓度范围内线性关系良好,相关系数(r~2)均大于0.99,检出限和定量下限分别为0.04～4.76μg/kg和0.07～8.24μg/kg,回收率为79.4%～110%,相对标准偏差为0.30%～7.5%。将所建方法应用于市售深加工羊肉制品中兽药残留的非定向筛查,检出样品含有磺胺二甲嘧啶以及标准数据库外的双氟沙星。该方法快速、准确、分析通量高,对于复杂基质中未知兽药残留鉴定具有重要意义。     

定性和定量分析磺胺氯吡嗪钠可溶性粉中的未知添加物

定性和定量分析了一批兽药磺胺氯吡嗪钠可溶性粉中的未知添加物。使用电位滴定法对该批磺胺氯吡嗪钠可溶性粉进行含量测定,发现滴定异常,根据标准进行的两项鉴别有一项不合格,因此怀疑添加了其他化合物。采用超高效液相色谱-四极杆-飞行时间质谱(UHPLC-Q/TOF MS)对该批样品进行筛查,发现疑似添加物,并使用高效液相色谱-二极管阵列检测(HPLC-DAD)法进行了双重确证和含量测定。该批样品中非法添加物为乙酰甲喹和磺胺二甲嘧啶,添加量分别为40.3和16.4 mg/g。通过总结该批样品非法添加物的发现、确证和含量测定的整个过程,得出一种较好的筛查未知物的模式,为兽药处方外非法添加筛查提供可借鉴的思路。     

液相色谱-离子阱-飞行时间质谱法定性分析未知着色剂

使用理化性质鉴别、紫外可见分光光度计、超快速液相色谱仪-二极管阵列检测器-离子阱-飞行时间串联质谱仪(UFLC-PDA-MS-IT-TOF)共同对用于"染色橙"的未知着色剂进行定性分析,并用超高效液相色谱-串联质谱(UPLC-MS/MS)进行确证。通过紫外光谱确定未知着色剂特征吸收波长,再用液相色谱分离,用PDA检测器可知其出峰时间,用质谱检测可知与其它干扰物质是否分离。在确定干扰物质与未知着色剂进行分离后,可以得到未知着色剂的分子离子峰和五级质谱碎片,根据碎片离子,推导出了裂解途径,并使用分子式软件预测了未知着色剂分子式。综合实验结果,最后定性了用于"染色橙"的未知着色剂为"橘红2号",其分子式为C18H16N2O3(m/z 309.1932)。用超高效液相色谱-串联质谱将未知着色剂与橘红2号标准品的保留时间、离子对m/z 309.3>153.3和m/z 309.3>278.3及离子比率进行比对,确证定性结果是准确的。本实验为未知物定性提供了一个有效的思路和方法。     

液相色谱-质谱法测定纺织品和皮革制品中痕量全氟辛烷磺酸盐

建立了纺织品和皮革制品中全氟辛烷磺酸盐(PFOS)的液相色谱-二级质谱(LC-MS2)测定方法。样品经0.1mol/L HCl和甲醇超声波振荡提取,高效液相色谱分离;色谱柱为Zorbax SB-C18;流动相为V(甲醇)∶V(10mmol/L乙酸铵水溶液)=70∶30,流速为0.3mL/min。采用负离子模式的电喷雾质谱检测。以一级质谱得到的准分子离子m/z499作为母离子,进行二级质谱(MS2)分析。选择MS2的碎片离子m/z169、230、280、330及419定性确证,MS2总离子流色谱(TIC)峰面积定量。实验优化了样品提取方法和色谱、质谱条件,并对二级质谱碎裂机理和特征离子进行了研究。结果表明,本法简便快速,准确可靠,相对标准偏差小于8.6%,回收率在90%~99%之间;检出限为1.5mg/kg,远低于欧盟指令50mg/kg的限量规定。本方法已成功应用于纺织品、皮革制品中痕量PFOS的测定。     

液相色谱/线性离子阱-静电场轨道阱高分辨质谱法快速筛查葡萄酒中的合成色素

基于液相色谱/线性离子阱-静电场轨道阱高分辨质谱(LC/LTQ-orbitrap MS)技术构建了合成色素的质谱数据库,利用精确质量数和该数据库中二级质谱图的匹配度分析筛查,建立了葡萄酒中15种水溶性合成色素的快速筛查方法。葡萄酒样品通过弱阴离子交换柱进行净化后经苯基色谱柱分离,然后用LTQ-orbitrap MS对样品中的色素进行筛查和定量检测。结果显示,葡萄酒中15种色素的检出限在0.00040~0.18 mg/L之间,3个加标水平的回收率在43.1%~127%之间,平均相对标准偏差均小于10%。加标样品的二级质谱图与数据库中标准样品二级质谱图的匹配度均达到98%以上。该方法可在无标准物质的情况下对葡萄酒中的15种合成色素进行筛查检测。     

同位素内标稀释液相色谱-串联质谱法测定鱼贝类组织中残留的环丙氟哌酸

建立了不同鱼贝类肌肉组织中以氘代同位素为内标测定环丙氟哌酸残留量的液相色谱-串联质谱(LC-MS/MS)方法。样品加入内标环丙氟哌酸-D8和磷酸盐缓冲溶液(pH 7.0)后进行匀质并用乙腈超声提取,经正己烷脱脂后采用Waters Oasis MAX小柱净化,在Cloversil-C18柱上,以乙腈-0.05%三氟醋酸(体积比为25∶75)为流动相,采用多反应监测(MRM)模式,液相色谱-电喷雾质谱法测定。根据环丙氟哌酸和氘代内标物的定量离子质量色谱图的峰面积比值,采用内标法定量。结果表明,环丙氟哌酸和内标的定量离子峰面积比值与环丙氟哌酸浓度在0.1～50.0 μg/kg范围内呈现良好的线性关系,相关系数为0.9991,方法的定量检测限为0.1 μg/kg,回收率为92.5%～98.1%,相对标准偏差(RSD)小于4.3%。将该方法用于市场上10种鱼和贝类样品的检测,结果表明该法具有灵敏、准确的优点,完全满足残留分析的确证检测要求。     

超高效液相色谱-电喷雾串联四极杆质谱法同时测定配合饲料中29种兽药

建立了同时测定配合饲料中喹诺酮类、磺胺类、大环内酯类和硝基呋喃类共计29种兽药的超高效液相色谱-电喷雾串联四极杆质谱(UPLC-ESI-MS/MS)检测方法。饲料样品用甲醇-乙腈(1:1, v/v)混合溶液提取,提取液经Oasis HLB固相萃取柱净化,采用UPLC-ESI-MS/MS检测。以甲醇和含0.1%(v/v)甲酸的水溶液作为流动相,进行梯度洗脱,用C18色谱柱分离,正离子模式扫描,多反应监测模式检测。29种兽药在0.01～5.0 mg/L范围内线性关系良好,相关系数(r)均大于0.99;在复合预混饲料、全价配合饲料、浓缩饲料中4个添加水平下29种兽药的平均回收率在61.2%～94.3%范围内,相对标准偏差(RSD)为2.2%～15.0%;方法的检出限(以信噪比大于10计)为0.01 mg/kg或0.05 mg/kg。该方法简便、快速、准确,重现性好,灵敏度高,适用于配合饲料中多种兽药的同时检测。     

超高效液相色谱-四极杆-飞行时间质谱法同时测定猪肉中多类兽药残留

建立了超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF MS)快速检测猪肉中6类33种兽药残留的分析方法。样品采用QuEChERS方法进行前处理(5%(v/v)乙酸乙腈溶液提取,C18和NH₂吸附剂净化),采用ZORBAX SB-C18色谱柱(100 mm×2.1 mm, 3.5 μm)分离,以乙腈-0.1%(v/v)甲酸水溶液(含5 mmol/L乙酸铵)为流动相,梯度洗脱,Q-TOF MS电喷雾正离子模式分析检测。在全扫描采集模式下,以准分子离子峰的峰面积定量,以化合物的色谱保留时间和精确质量数定性。在Target MS/MS采集模式下,通过碎片离子的精确质量数进一步确证化合物。33种化合物在各自的线性范围内均呈现良好的线性关系,相关系数均大于0.99, 33种化合物的定量限(S/N=10)为2.5~100 μg/kg,添加回收率为67.0%~109.0%,相对标准偏差(RSD,n=6)均不高于15.1%。该方法简便、快速、灵敏,适用于猪肉中多类兽药残留的同时检测。     

Determination of levamisole in feeds by liquid chromatography coupled to electrospray mass spectrometry on an ion trap

Test methods have to be developed by laboratories for official control to monitor possible misuse of veterinary drugs in animal productions, also through feeding stuff. A novel method for identification and quantification of levamisole in feeds by liquid chromatography coupled to electrospray mass spectrometry in an ion trap (LC/ESI‐MS/MS) is herein described; after a single‐step cleanup by liquid‐liquid extraction from the feed and separation by reversed‐phase liquid chromatography, levamisole was determined and unambiguously confirmed by tandem mass spectrometry, on the basis of two product ions. The method was in‐house validated, according to the Regulation 882/2004/EC, evaluating trueness, repeatability, within‐laboratory reproducibility, ruggedness, specificity, and the limit of quantification (LOQ). The method is reliable and specific for complete and complementary feeds for pigs, cattle, rabbits and poultry; very good mean recoveries (higher than 92 %) and precision (RSD values < 15.2%) were attained. The LOQ at 2.0 mg/kg was verified. Moreover, we describe how the method was developed to support Italian Police investigations regarding illegal treatments of pigs; in this case, since the drug(s) added to the feed were unknown, a preliminary untargeted analysis was performed by full scan mass spectrometry on an ion trap, from 50 up to 2000 m/z; the presence of levamisole was hypothesised, on the basis of the most abundant ion and its fragmentation pattern. Then, levamisole was unambiguously confirmed by the ion trap LC/ESI‐MS/MS method. Copyright © 2012 John Wiley & Sons, Ltd.     

高效液相色谱-串联质谱法测定食品中硝磺草酮

1 引 言 硝磺草酮(Mesotrione),化学名2-(4-甲磺酰基2硝基苯甲酰基)环己烷1,3二酮,又名甲基磺草酮、硝磺酮,是瑞士先正达公司发明的玉米田芽前和苗后广谱选择性除草剂,因具有低毒性、高活性、对环境友好等特点[1,2],是近几年广泛使用的除草剂.但最近研究发现,硝磺草酮具有高效的起始活性和残留活性,长期食用含有硝磺草酮残留的食物会对人畜产生致癌作用,或引起胎儿畸形[3,4].欧盟和世界贸易组织对浆果、亚麻籽、越橘、栗草料等物质中硝磺草酮的限量为0.05 mg/kg.而美国、加拿大等国对芦笋、草杆、草料等物质中硝磺草酮的限量为0.01 mg/kg[10-13].     

Comprehensive comparison of liquid chromatography selectivity as provided by two types of liquid chromatography detectors (high resolution mass spectrometry and tandem mass spectrometry): “Where is the crossover point?”

The selectivity of mass traces obtained by monitoring liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was compared. A number of blank extracts (fish, pork kidney, pork liver and honey) were separated by ultra performance liquid chromatography (UPLC). Detected were some 100 dummy transitions respectively dummy exact masses (traces). These dummy masses were the product of a random generator. The range of the permitted masses corresponded to those which are typical for analytes (e.g. veterinary drugs). The large number of monitored dummy traces ensured that endogenous compounds present in the matrix extract, produced a significant number of detectable chromatographic peaks. All obtained chromatographic peaks were integrated and standardized. Standardisation was done by dividing these absolute peak areas by the average response of a set of 7 different veterinary drugs. This permitted a direct comparison between the LC-HRMS and LC-MS/MS data. The data indicated that the selectivity of LC-HRMS exceeds LC-MS/MS, if high resolution mass spectrometry (HRMS) data is recorded with a resolution of 50,000 full width at half maximum (FWHM) and a corresponding mass window. This conclusion was further supported by experimental data (MS/MS based trace analysis), where a false positive finding was observed. An endogenous matrix compound present in honey matrix behaved like a banned nitroimidazole drug. This included identical retention time and two MRM traces, producing an MRM ratio between them, which perfectly matched the ratio observed in the external standard. HRMS measurement clearly resolved the interfering matrix compound and unmasked the false positive MS/MS finding.     

Ionization enhancement in atmospheric pressure chemical ionization and suppression in electrospray ionization between target drugs and stable-isotope-labeled internal standards in quantitative liquid chromatography/tandem mass spectrometry

The phenomena of ionization suppression in electrospray ionization (ESI) and enhancement in atmospheric pressure chemical ionization (APCI) were investigated in selected-ion monitoring and selected-reaction monitoring modes for nine drugs and their corresponding stable-isotope-labeled internal standards (IS). The results showed that all investigated target drugs and their co-eluting isotope-labeled IS suppress each other's ionization responses in ESI. The factors affecting the extent of suppression in ESI were investigated, including structures and concentrations of drugs, matrix effects, and flow rate. In contrast to the ESI results, APCI caused seven of the nine investigated target drugs and their co-eluting isotope-labeled IS to enhance each other's ionization responses. The mutual ionization suppression or enhancement between drugs and their isotope-labeled IS could possibly influence assay sensitivity, reproducibility, accuracy and linearity in quantitative liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). However, calibration curves were linear if an appropriate IS concentration was selected for a desired calibration range to keep the response factors constant.     

QuEChERS结合液相色谱-串联质谱法快速测定猪肉中多类兽药残留

采用改进的QuEChERS方法提取和净化猪肉样品,建立了同时测定磺胺类、磺胺类增效剂、β-受体激动剂、四环素类、喹诺酮类、金刚烷胺和性激素共7类35种兽药残留的液相色谱-串联质谱（LC-MS/MS）检测方法。样品经 Na₂EDTA（乙二胺四乙酸）-Mcllvaine缓冲液-2.5%（体积分数）乙酸乙腈溶液提取,提取液经盐析后取乙腈相,用氨基（NH₂）吸附剂分散固相萃取净化后,在电喷雾离子源正离子多反应监测（MRM）模式下进行测定,基质外标法定量。35种兽药在1.0～50.0 μg/L范围内线性关系良好,相关系数均大于0.996。在3个不同添加水平下的平均回收率为71.8%～113.5%,相对标准偏差为0.6%～9.8%（n=6）,检出限和定量限分别为0.01～1.01 μg/kg和0.04～3.37 μg/kg。该方法操作简单,净化效果好,灵敏度高,适用于猪肉中兽药多残留的同时快速定性、定量分析。     

利用固相萃取-气相色谱-负化学离子源质谱技术快速分析茶叶中3种杀螨剂和八氯二丙醚农药残留

建立了茶叶中3种杀螨剂及八氯二丙醚农药残留快速分析的固相萃取-气相色谱-负化学离子源质谱检测(GC-NCI-MSD)方法,并应用于出口欧盟茶叶中农残检测及基地监管.样品经正己烷-丙酮(1∶1,V∶V)提取后,用固相萃取柱(Agela)除去茶叶中干扰物质,以环氧七氯为内标物,经气相色谱-负化学离子源质谱分时段选择离子监测...     

Multi-class confirmatory method for analyzing trace levels of tetracyline and quinolone antibiotics in pig tissues by ultra-performance liquid chromatography coupled with tandem mass spectrometry

An ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC/MS/MS) method was developed to screen and confirm multi-class veterinary drug residues in pig tissues including pig kidney, liver and meat. Twenty-one drugs of two different classes including seven tetracyclines and four types of quinolones (quinoline, naphthyridine, pyridopyrimidine and cinoline) were determined simultaneously in a single run. The homogenized sample tissues were extracted with EDTA-McIlvaine buffer solution and further purified using a polymer-based Oasis HLB solid-phase extraction (SPE) cartridge. An ACQUITY UPLC BEH C18 column was used to separate the analytes followed by tandem mass spectrometry using an electrospray ionization source. MS data acquisition was performed in the positive ion multiple reaction monitoring mode, selecting two ion transitions for each target compound. Recovery studies were performed at different fortification levels. The overall average recoveries from pig muscle, kidney, and liver fortified with quinolones and tetracyclines at three levels ranged from 80.2 to 117.8% based on the use of matrix-fortified calibration with the coefficients of variation ranging from 2.1 to 17.8% (n=6). The limits of quantitation (LOQs) of quinolones and tetracyclines in different tissues ranged from 0.03-4.50 microg/kg and 0.16-10.00 microg/kg, respectively. The effects of the extraction solvent, SPE cartridge, elution solvent and sample matrix on the analyte recovery as well as the effects of the mobile phase composition and column temperature on the chromatographic behavior were also studied.     

高效液相色谱-串联质谱法测定蜂胶原胶中氯霉素的残留量

建立了高效液相色谱-串联质谱法(HPLC-MS/MS)测定蜂胶原胶中氯霉素残留量的分析方法。样品用叔丁基甲醚溶解,氢氧化钠溶液去除黄酮类等杂质,叔丁基甲醚层加正己烷降低氯霉素的溶解度,再用乙酸钠缓冲液反萃氯霉素,反萃溶液调至碱性后用乙酸乙酯萃取,经浓缩、复溶和过滤后,进行测定。采用甲醇-水(65∶35,体积比)为流动相,反相Atlantis T_3色谱柱进行液相色谱分离,电喷雾负离子电离(ESI-),多反应监测模式(MRM)进行检测,内标法定量。结果表明,氯霉素在0.1~5.0μg/L范围内线性关系良好;方法的定量下限(S/N≥10)为0.3μg/kg;在0.3、0.6、3.0μg/kg加标水平下,氯霉素的平均回收率为97.3%~103%,相对标准偏差为4.8%~6.4%。该法的灵敏度、准确度和精密度均符合兽药残留检测的要求。