高效液相色谱-串联质谱法测定豆芽中4-氯苯氧乙酸钠

目的建立豆芽中4-氯苯氧乙酸钠的液相色谱-串联质谱测定方法。方法豆芽样品均质后以0.01mol/L氢氧化钠溶液提取,提取液经酸化后再用乙酸乙酯萃取,收集经离心分层的有机相,浓缩后用甲醇溶解进行测定分析。以甲醇和0.1%甲酸(FA)水溶液为流动相,采用Hypersil GOLD a Q(100 mm×2.1 mm,3μm)色谱柱分离,电喷雾电离负离子条件下以选择反应监测模式(SRM)检测。结果该方法检出限0.005 mg/kg,在1~100 ng/m L范围内具有良好线性,相关系数为0.9998。回收率为79.1%~104.7%,相对标准偏差低于5%(n=6)。结论该方法前处理简单快速,定性准确,灵敏度好,适用于豆芽中4-氯苯氧乙酸钠的残留检测。     

液相色谱-电喷雾串联质谱法定量葱蒜类植物中Se-甲基-硒半胱氨酸的最佳提取条件研究

目的研究适于液相色谱-电喷雾串联质谱法(LC-MS/MS)定量测定富硒葱蒜类植物中Se-甲基-硒半胱氨酸(MSeC)的提取液的最佳制备条件。方法用4种提取剂(纯水、甲醇、丙酮和乙酸乙酯)、2种提取方法(超声提取和沸水提取)、不同水提取温度(70、80、90和100℃)和时间(45、60、75和90min)对富硒大蒜中的MSeC的最佳提取条件依次筛选研究,获得满足最大量测得MSeC的样品制备方法。按照选择条件提取洋葱、韭葱和大葱加标粉制剂,并采用LC-MS/MS测定MSeC含量,计算加标回收率。结果4种提取剂的超声提取对比分析发现,纯水提取蒜粉中MSeC的量最大,沸水浴加热比单独超声处理能够提高蒜粉中MSeC的提取率。水加热提取温度和时间二因素正交设计优选实验证实,蒜粉中MSeC最佳提取制备条件为100℃提取90min,该提取条件处理其他葱蒜类粉制剂的MSeC加标回收率在91%～108%之间。结论沸水提取90min适用于LC-MS/MS在线定量分析葱蒜类植物中MSeC的待测液的制备。     

高效液相色谱-电喷雾串联质谱法测定保健食品中水苏糖含量

目的以质谱定性定量,测定保健品中水苏糖含量。方法采用高效液相色谱/电喷雾质谱联用法(HPLC-ESI/MS),色谱柱:瑞典KromasilNH2柱;流动相:甲醇+乙腈+0.1%甲酸氨水溶液=8+52+40(体积比);流速1.0ml/min。质谱采用电喷雾正离子模式(ESI+),对m/z689进行选择离子监测,扫描范围(m/z):620～700amu。结果水苏糖在80～120μg/ml范围内,峰面积和浓度呈良好的线性关系(r=0.9992);相对标准偏差(RSD)为0.73%;在3个添加水平下的回收率均在93.0%～105.8%。结论本方法快速、选择特异性高、分析时间短且无需衍生处理,抗干扰能力强,能准确快速测定水苏糖的含量。     

Quantitative determination of ceftiofur-related residues in bovine raw milk by LC-MS/MS with electrospray ionization

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of ceftiofur-related metabolites that retain the ß-lactam structure, expressed as desfuroylceftiofur free acid has been developed and validated for raw bovine milk. The method described is based on the cleavage of the disulfide and/or thioester bonds between the metabolites and their sulfur-containing moiety, using dithioerythritol to yield desfuroylceftiofur and further stabilization to desfuroylceftiofur-acetamide (DCA) using iodacetamide. The final extract containing the DCA derivative was cleaned up by a simple solid-phase extraction step prior to separation on a phenylether reversed phase HPLC-column. Chromatography was performed using a formic acid/methanol gradient. Collision induced dissociation with argon was used for fragmentation of the pseudomolecular ion [M+H]⁺ to achieve the required specificity of the method. The new EU guidelines for identification and quantification were fulfilled.     

超高效液相色谱-质谱法测定果酱中纳他霉素残留

目的建立了果酱中纳他霉素的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。方法样品加入0.5g氯化钠、经10ml丙酮萃取,以甲醇-水溶液为流动相进行梯度洗脱,经BEHC18色谱柱分离,通过多反应监测模式(MRM)进行测定。结果纳他霉素在蓝莓果酱、葡萄树莓果酱、香蕉草莓果酱、黄桃果酱、苹果果酱和山楂草莓果酱中的线性范围分别为0.5～25.0、0.5～25.0、1.0～25.0、1.0～25.0、0.5～25.0和1.0～25.0μg/kg,相关系数(R2)均大于0.99。6种果酱中目标化合物的定量限为0.5～1.0μg/kg,3个浓度水平的加标回收率为80.1%～113.3%,相对标准偏差(RSD,n=5)小于20%。结论该方法快速、准确、操作简便,可用于果酱中纳他霉素的确证和定量分析。     

Azaspiracid shellfish poisoning: unusual toxin dynamics in shellfish and the increased risk of acute human intoxications

A number of recent acute human intoxications in Europe from the consumption of Irish mussels have been attributed to the presence of a new class of toxins named azaspiracids. The study demonstrates that azaspiracids behave differently from other polyether toxins, and this accounts for most false-negative results in the mouse bioassay employed by regulatory agencies to detect azaspiracids. Typically, polyether toxins are concentrated in the digestive glands of shellfish, but this is not always the situation with azaspiracids. Liquid chromatography-mass spectrometry (LC-MS), especially multiple tandem MS methods, have been applied to demonstrate that azaspiracid (AZA1) and its methyl- and demethyl- analogues, AZA2 and AZA3 respectively, are distributed throughout shellfish tissues. Using conventional mouse bioassay protocols, only 0-40% of the total azaspiracid content of shellfish was used in the assay, which could directly account for false-negative results. It was also observed that the toxin profiles differed significantly in various mussel tissues with AZA1 as the predominant toxin in the digestive glands and AZA3 predominant in the remaining tissues.     

QuEChERS结合高效液相色谱-串联质谱法测定粮谷中16种真菌毒素

建立了QuEChERS结合高效液相色谱-串联质谱仪(HPLC-MS/MS)同时测定粮谷中16种真菌毒素残留量的方法,样品经乙腈-水-乙酸(84∶15∶1,v/v)溶液超声提取,提取液采用C18、MgSO4净化,净化液过0.22μm微孔滤膜,用HPLC-MS/MS分析检测。Acquity UPLC BEH C18柱为分析柱,甲醇/乙腈(4+6)-0.1%甲酸水溶液为流动相进行梯度洗脱,采用电喷雾正负离子(ESI+、ESI-)模式同时电离,多反应监测(MRM)模式检测,外标法定量。结果表明,16种真菌在相应的浓度范围内线性关系良好(相关系数r2>0.995),方法定量限为0.3~3.5μg/kg,在低、中、高3个不同浓度的添加水平下,平均回收率为90.6%~106.5%,相对标准偏差≤8.8%(n=6),满足日常检测要求。该方法前处理简单,测定快速、准确,灵敏度高,适用于粮谷中16种真菌毒素残留的定性和定量分析。     

液相色谱-串联质谱法同时测定玉米粉中6种真菌毒素

建立了同时测定玉米粉中6种真菌毒素的液相色谱-串联质谱法.采用乙腈-0.3%乙酸水溶液超声提取样品中的待测物,吹干有机溶剂后,提取液经HLB固相萃取小柱净化,浓缩吹干后用流动相定容,LC-MS/MS检测.该方法检出限低,在0.03～4.0μg/kg添加水平内,回收率在66.7%～90.2%之间,变异系数在7.1%～11.7%.结果表明,该法灵敏,准确,适用于玉米粉中6种真菌毒素含量的同时测定.     

Analysis of ochratoxin A in pig kidney and rye flour using liquid chromatography tandem mass spectrometry (LC/MS/MS)

A liquid chromatography electrospray tandem mass spectrometric (LC/MS/MS) method is described for analysis and confirmation of ochratoxin A in pig kidney and rye flour using derivatization of ochratoxin A to the methyl ester. Ochratoxin A methyl(d₃)ester is used as internal standard. The method works well, the detection limit is 0.02 μ g/kg and the repeatability (coefficient of variation) is between 6% and 16% in the contamination range 0.5 to 8 μ g/kg.     

Screening assay of angiotensin-converting enzyme inhibitory activity from complex natural colourants and foods using high-throughput LC-MS/MS

Inhibition of angiotensin-converting enzyme (ACE) by various foods decreases the blood pressure. ACE inhibitors derived from natural components may be of therapeutic value in preventive medicine. In this study, we report a novel screening assay of ACE inhibitors from complex natural colourants and foods that employ solid phase extraction (SPE), high-throughput liquid chromatography (LC) separation, and stable isotope dilution electrospray tandem mass spectrometry (SID-ESI-MS/MS). When a target sample was subjected to N-Hippuryl-His-Leu (HHL) and ACE in phosphate buffer (pH 7.4), generated hippuric acid (HA) was extracted by SPE. LC/SID-ESI-MS/MS detection of HA allowed us to accurately identify the effects of complex substances such natural colourants and foods that inhibit the ACE of HHL. The major HA and HA-d₅ fragment ions at m/z 180 → 105 and 185 → 110 in the multiple reaction monitoring (MRM) mode can quantify levels that are lower than other methods. The LC/SID-ESI-MS/MS method described here is a rapid, selective, sensitive, and highly reproducible method for the determination of HA in various samples. Based on the assay developed, all samples such as natural colourants, infant formula, soy paste, ketchup, mayonnaise, wheat flour, orange juice, supplement drink, tea, and coffee could be accurately measured for ACE inhibition in various matrices. High-throughput LC/SID-ESI-MS/MS assay has no limitations in the evaluation of inhibition activity in various natural samples such as colour, high-matrix, and processed foods.     

HPLC/ESI-MS测定减肥保健食品中的双去甲基西布曲明

目的建立高效液相色谱质谱联用技术(HPLC/ESI-MS)的测定方法,测定保健食品中双去甲基西布曲明。方法色谱条件为Johnson Spherigel C18色谱柱(4.6mm×250mm,5μm);流动相:流动相A液(0.25%乙酸+20mmol/L乙酸铵),流动相B液(甲醇)=25+75(体积比),流速1ml/min,检测波长223nm。质谱采用电喷雾正离子模式(ESI+),分子离子峰m/z252。结果双去甲基西布曲明在0.01~1.20mg/ml范围内,浓度与峰面积呈良好的线性关系,最低检出限为0.95μg/ml(S/N=3)。结论本方法流动相简单,分析时间短且试样预处理简单,灵敏度高,借助质谱的定性能力,可大大提高方法可靠性和抗干扰能力,能准确快速地测定保健食品中的双去甲基西布曲明。     

Screening assay of residual antibiotics in livestock samples by LC-MS/MS

A LC-MS/MS screening assay of multi-class antibiotics was developed for 19 residual antibiotics in livestock samples. Sample preparation employed the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach using 0.5% formic acid in acetonitrile-methanol (8 : 2), with salting-out using magnesium sulfate, trisodium citrate and sodium chloride. Recovery values from 5 different livestock samples ranged from 45.5 to 121.6%, and the RSDs were under 18% at two concentration levels. The limit of quantification values of 19 analytes were under 10 μg/kg in all livestock samples, and the procedure can detect almost all analytes under the MRL. Screening capability was confirmed by employing spiked samples. This new screening assay for residual antibiotics in livestock samples is expected to be useful for routine laboratory tests.     

液相色谱-质谱法测定保健食品中的三价铬及六价铬含量

目的建立液相色谱-质谱法测定保健食品中总铬、三价铬及六价铬含量的分析方法,并与原子吸收法的检测结果进行比较。方法利用液相色谱-质谱法测定提取和氧化反应前后样品溶液中六价铬,分别计算总铬、三价铬和六价铬的量。结果 8批样品(3批胶囊,5批片剂)测定六价铬和总铬含量分别为188.7~257.8mg/kg和189.1~257.4 mg/kg。该方法可以实现保健食品中总铬、三价铬和六价铬的测定,六价铬的方法检出限为0.03 mg/kg,RSD=3.72%(n=5),定量限为1.0 mg/kg,RSD=3.07%(n=5)。结论该方法简便易行,与原子吸收法测定总铬的结果一致,可用于保健食品中铬及其形态的测定。     

全碳标记稳定同位素内标-超高效液相色谱-串联质谱法测定粮食中16种真菌毒素

考察高效液相色谱-串联质谱-全碳标记的稳定同位素内标法精确测定小麦和玉米中16种真菌毒素方法的适用性。样品经提取稀释、加入内标,高效液相色谱-串联质谱测定。结果表明,16种真菌毒素线性相关系数大于0.997,3个水平的添加回收率为83%~114.3%,相对标准偏差为0.9%~13%,定量限为0.5~200μg/kg,通过检测FAPAS04223质控样品和小麦、玉米样品验证了方法的准确性和适用性,能够快速、批量、准确的测定小麦和玉米中16种真菌毒素,为我国粮食真菌毒素污染监测提供便利。     

Structural characterization of metabolites after the microbial degradation of type A trichothecenes by the bacterial strain BBSH 797

Contamination of feed with trichothecenes, a group of Fusarium mycotoxins, leads to losses in performance due to their immunosupressive effects and the negative effect on the gastrointestinal system in animal production. A possible way of detoxification is microbial degradation, which was the focus of this study. A bacterial strain - BBSH 797 - which can degrade some mycotoxins of the trichothecene group, has already been isolated. It transforms deoxynivalenol (DON) into its metabolite DOM-1, the non-toxic deepoxide of DON. Analogous to the microbial degradation of DON, the transformation of six different type A trichothecenes was observed. The metabolites appearing were characterized by GC-MS after derivatization with TRI-SIL®TBT. Two metabolites were additionally identified by liquid chromatography-mass spectrometry with particle beam interface (LC-PB-MS) with electron impact (EI)-ionization mode. The major finding was that scirpentriol was completely transformed into its non-toxic metabolite deepoxy scirpentriol, while the mycotoxin T-2 triol underwent a more complicated metabolism. According to the study, T-2-triol was degraded into its non-toxic deepoxy form and into T-2 tetraol, which was then further metabolized to deepoxy T-2 tetraol. GC-MS after derivatization with TRI-SIL®TBT was suitable for the structural characterization of trichothecenes and their degradation products. Besides the mass spectra of already known degradation products, spectra of new metabolites could be recorded by LC-PB-MS.     

Analysis of glyphosate residues in cereals using liquid chromatography-mass spectrometry (LC-MS/MS)

A fast and specific method for the determination of glyphosate in cereals is described. The method is based on extraction with water by ultrasonication. The samples are cleaned up and separated by high-performance liquid chromatography on a polystyrene-based reverse-phase column (clean-up) in series with an ion chromatography column (separation) using NaHCO₃ as eluent. A micro-membrane suppressor was inserted after the separator column to remove the Na⁺ ions before detection by electrospray ionization mass spectrometry in the negative-ion mode. In MS/MS, mode the following transitions were monitored m/z 168 →150 (glyphosate) and 170 →152 (internal standard 2-¹³ C¹⁵N-glyphosate) for quantification. The mean recovery was 85% (n=32) at spiking levels from 0.03 to 0.33 mg kg^-1. From 1998 to 2001, from the analysis of about 50 samples per annum, a reduction in the glyphosate residues was observed owing to a Danish trade decision not to use grain with glyphosate residues for milling or bread production.     

烟气中烟草特有亚硝胺LC-MS/MS分析方法的改进

为更加快速准确地测定不同类型卷烟烟气中TSNAs含量,进行了液相色谱串联质谱(LC-MS/MS)法测定条件改进试验。结果表明:①10 mmol/L乙酸铵水溶液可以替代100 mmol/L乙酸铵水溶液作萃取剂;②萃取液经0.45μm水相滤膜过滤后可直接进行LC-MS/MS仪分析;③同时用NNN-d4,NNK-d4,NAT-d4,NAB-d4作内标定量结果更为准确;④TSNAs的检出限为0.06~0.14 ng/mL,回收率91%~100.6%,RSD 0.76%~5.42%。该方法适用于混合型、烤烟型卷烟样品主流烟气中TSNAs的定量分析。     

粮谷中三环唑残留量的液相色谱-质谱/质谱检测

本文建立了玉米、大麦、糙米、大米、小麦五种粮谷基质中三环唑残留量的液相色谱-质谱／质谱检测方法。样品经丙酮涡旋振荡提取,再经中性氧化铝固相萃取柱净化后,由液相色谱-质谱／质谱检测,外标法定量。方法的定量限为0.01 mg/kg,标准品浓度在2.5 ng/mL~80 ng/mL呈良好的线性关系,相关系数大于0.99。 粮谷样品在0.01、0.02和3.00 mg／kg添加水平的回收率范围分别为72.1%~95.6%,73.0%~95.4%,80.1%~99.2%,相对标准偏差范围在2.2%~7.4%。本方法方便、快速、溶剂消耗低、灵敏度高、回收率稳定,可以满足进出口粮谷中三环唑残留量的检测需求。     

Development and Application of a Method for the Analysis of 9 Mycotoxins in Maize by HPLC‐MS/MS

A reliable and sensitive liquid chromatography/tandem mass spectrometry (LC‐MS/MS) method was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA), fumonisin B₁ (FB₁), and T2‐toxin in maize. The samples were first extracted using acetonitrile: water: acetic acid (79 : 20 : 1), and then further cleaned‐up using OASIS HLB cartridge. Optimum conditions for the extraction and chromatographic separation were investigated. The mean recoveries of mycotoxins in spiked maize ranged from 68.3% to 94.3%. Limits of detection and quantification ranged from 0.01 to 0.64 μg/kg and from 0.03 to 2.12 μg/kg, respectively. The LC‐MS/MS method has also been successfully applied to 60 maize samples, which were collected from Shaanxi Province of China. Twenty‐four of the total 60 samples (40%) were contaminated with at least 1 of these 9 mycotoxins. Occurrence of mycotoxins were 6.7%, 1.7%, 3.3%, 6.7%, 1.7%, 23.3%, and 3.3% for AFB₁, AFB₂, OTA, ZEA, DON, FB₁, and T2‐toxin, respectively. The results demonstrated that the procedure was suitable for the simultaneous determination of these mycotoxins in maize matrix.