固相萃取-高效液相色谱串联质谱测定牛奶中9种性激素残留

采用固相萃取-高效液相色谱质谱联用法(SPE-HPLC/MS),建立牛奶中9种性激素(雌酮、雌三醇、17α-雌二醇、诺龙、甲睾酮、丙酸睾酮、醋酸氯地孕酮、醋酸甲地孕酮、醋酸甲羟孕酮)残留的检测方法。样品经甲醇提取,过固相萃取柱净化,氮气吹干,残留物甲醇溶解后测定。其中雌激素(雌酮、雌三醇、17α-雌二醇)采用负模式;其余性激素为正模式,进行多反应监测(MRM)模式定性定量分析。雌激素检出限(LODs)为1.1~1.2μg/L,定量限(LOQs)为3.63~3.96μg/L;其余性激素检出限(LODs)为0.1~0.5μg/L,定量限(LOQs)为0.33~1.65μg/L;分别在20.0~500.0μg/L及2.5~100.0μg/L范围内线性关系良好(r20.994 4)。在50.0~100.0μg/L的添加水平上,9种性激素的平均回收率在82.7%~98.2%之间,变异系数(CV)为4.2%~11.2%。该法操作简单、灵敏度高,可用于牛奶中9种性激素的测定。     

分散固相萃取-高效液相色谱串联质谱法测定水产品中氯霉素类药物的残留量

本文采用分散固相萃取技术作为前处理手段,结合高效液相色谱串联质谱(HPLC-MS/MS)高灵敏度和高选择性的优势,建立了一种水产品中氯霉素类药物残留的检测方法。实验探讨和优化了以分散固相萃取净化样液过程中的提取条件、固体吸附剂的用量等。并优化检测方法的色谱、质谱条件,采用多反应监测模式(MRM)对目标物进行定性、定量分析。结果表明,目标物在一定的浓度范围内具有良好的线性关系;方法的检出限为0.07～0.10μg·kg~(-1)。对样品进行三个水平加标实验,目标化合物的回收率为88.81%～102.89%,相对标准偏差(RSD,n=6)为2.30%～4.87%。该方法定性定量准确,灵敏度高,有效去除基质干扰,适用于水产品中氯霉素类药物残留量的定性、定量分析。     

固相萃取-高效液相色谱法测定水中邻苯二甲酸酯类的方法研究

建立了固相萃取-高效液相色谱法测定水中5种邻苯二甲酸酯类的方法。通过正交实验确定了固相萃取的最优化条件：洗脱剂组成（乙醚：甲醇）19：1,洗脱速率1．0mL／min,洗脱体积9mL,清洗剂组成（甲醇：水）1：19。液相色谱的最佳条件：检测波长224nm,流速1．0mL／min,采用梯度洗脱,开始时甲醇-水（75：26,V／V）,保持6min,第7min甲醇比例上升到100％。结果,5种物质峰面积对浓度进行线性回归的相关系数均大于0．9992,该方法的最低检出限在（0．01～0．07）pg／L之间,加标回收率82．1％～97．4％,相对标准偏差（RSD）1．1％～2．4％。     

固相萃取-超高效液相色谱质谱联用法测定水产品中左氧氟沙星残留

建立了水产品中左氧氟沙星残留的超高效液相色谱串联质谱检测法。采用乙腈对样品中的待测物进行提取,正已烷除脂,浓缩后用固相萃取小柱进行净化,吹氮浓缩后采用超高效液相色谱质谱联用-电喷雾正离子和MRM多反应监测模式进行定性定量分析。检测浓度线性范围为0～100μg/kg,线性相关系数为0.9922,检出限为4.5μg/kg。在鳗鱼、虾和罗非鱼三种不同样品基质中进行添加浓度为10,20,50μg/kg的验证试验,该药物的回收率在72.5%～83.5%内,相对标准偏差(n=6)在7.9～11.4%之间,并对其质谱裂解和基质效应进行了研究。本检测方法快速,高效,灵敏度高,符合检测要求。     

固相萃取-液相色谱串联质谱法测定葡萄酒中27种农药残留

建立固相萃取-液相色谱串联质谱的分析方法同时检测葡萄酒中27种农药残留。葡萄酒样品经乙腈超声提取,进行40℃旋转蒸发后,使用CARB/PSA双层SPE小柱进行净化,采用C18色谱柱分离,以含甲酸的乙酸铵缓冲液和乙腈为流动相进行梯度洗脱,在质谱的正离子多反应监测(MRM)模式下进行检测。结果表明:该方法对空白葡萄酒加标水平下27种农药残留的测定线性良好,检测下限(10S/N)在2.5~10μg·kg-1之间,分别在不同3个浓度水平上用标准加入法进行回收试验,平均回收率在60~88%之间,相对标准偏差(n=6)在5.5到16.2%之间。该方法快速准确,灵敏度好,可满足葡萄酒产品的日常检测。     

固相萃取-高效液相色谱-串联质谱法同时测定尿液中16种羟基多环芳烃

建立固相萃取-高效液相色谱-串联质谱法同时测定人体尿液中16种羟基多环芳烃（OH-PAHs）的含量。试样经过β-葡萄糖苷酸酶/硫酸酯酶酶解,HLB小柱富集净化,氮吹浓缩后0.1%维生素C乙腈溶液复溶,Agilent Eclipse PAH(2.1 mm×100 mm, 1.8μm)分离,负离子多反应监测模式测定。各羟基多环芳烃线性范围良好,相关系数均>0.99,方法检出限范围为0.015～0.06 ng/mL,平均加标回收率范围为71.25%～114.07%。30份人体尿样检测结果显示2-OHNap、1-OHNap、2-OHFlu等10种均有检出,其检出率范围为23.33%～100%。该方法具有操作简便、灵敏度高、准确性好、适用性强、检测效率高、检测成本低等特点,可满足人体尿液中16种羟基多环芳烃含量的同时准确测定需要。     

分散固相萃取-高效液相色谱-串联质谱快速测定鸡肉中盐霉素残留

建立了分散固相萃取-超高效色谱-电喷雾串联质谱快速测定鸡肉中盐霉素残留的方法。样品经乙腈提取后,采用QuEChERS方法净化,氮吹转换溶剂后,采用Acquity BEH C18柱进行分离,0.3%甲酸水溶液-甲醇体系为流动相,梯度洗脱,电喷雾质谱正离子多反应监测模式测定,外标法定量。结果表明,在优化的条件下对样品进行分析检测,盐霉素的检出限为0.03μg·kg-1,添加水平为5.5~31.4μg·kg-1时,加标回收率为78.2-97.8%,RSD<2.0%(n=6),在0.630~25.2μg·L-1质量浓度范围内呈良好线性,相关系数R2>0.9989。该方法前处理步骤简单,具有较高灵敏度,可用于大批量样品的快速筛查检测。     

固相萃取-超高效液相色谱-串联质谱法测定育苗水中矮壮素和助壮素残留量及其消解动态

建立了育苗水中矮壮素和助状素的固相萃取-超高效液相色谱-串联质谱法(SPE-UPLC-MS/MS)测定方法。样品直接采用弱阳离子固相萃取柱净化;在粒径5μm的亲水作用色谱柱上用SeQuant ZLC-HILIC MEKCK色谱柱进行分离;电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测。以保留时间和特征离子定性、外标法定量。结果表明矮壮素和助状素在0.2~10 ng/mL的空白添加浓度范围内线性良好(r2>0.999),在2.0、5.0、10ng/mL的添加水平范围内,平均回收率分别为89.1.0%~107.1%和102.3%~105.4%,相对标准偏差(RSD)分别为8.5%~29.5%和5.5%~23.0%,矮壮素和助壮素的检出限(LOD)为0.005ng/mL,测定低限(LOQ)为0.02ng/mL,水体中矮壮素和助状素的消解动态研究结果表明,矮壮素和助状素在水体中消解速度缓慢,施药42天后才能减少到96%以上。     

超高效液相色谱-串联质谱法对鳗鱼及制品中禾草丹残留量的测定

本文建立了用超高效液相色谱-串联质谱法对鳗鱼及制品中禾草丹的检测方法。采用乙腈对样品中的禾草丹进行提取,浓缩后用固相萃取SPE小柱、氧化铝、无水硫酸钠进行净化,最后用超高效液相色谱-质谱联用法进行分离和定性定量分析。方法线性相关系数为0.9966,5-20μg/kg,加标样品的回收率在75%-85%之间,相对标准偏差在8.3%-12.7%,定量检出限可达到0.5μg/kg,该方法具有快速、高效、灵敏度高,符合出口检测限量的要求。     

分散固相萃取高效液相色谱质谱法测定烟叶中3种农药残留

本文建立超高压液相色谱-质谱法同时测定烟叶中吡虫啉、茚虫威、莠去津三种农药残留检验方法.烟叶样品经溶剂均质后采用可靠和安全的分散固相萃取(DisQuE净化管)技术提取、净化后备用.以0.08％甲酸+9.6 mmol/L乙酸铵水溶液—乙腈作为流动相,采用梯度洗脱,超高压液相色谱-质谱经条件优化后对标样进行测定,实验结果表...     

Multiclass determination of sunscreen chemicals in water samples by liquid chromatography-tandem mass spectrometry

A novel analytical method based on solid-phase extraction (SPE) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) for the determination of UV sunscreen agents in the water environment is presented. After a thorough investigation of SPE and LC-MS/MS conditions, it permits the enrichment and determination of nine of these compounds in a single methodology, including three very polar sulfonates (e.g., 2-phenylbenzimidazole-5-sulfonic acid, PBSA) and six other less polar compounds (e.g., benzophenone-3, BP-3; octocrylene, OC,...). Other important matters of concern in the determination of UV filters at trace levels in water, i.e., adsorption on glassware and blank contamination problems, have also been discussed and minimized. This methodology affords detection limits between 7 and 46 ng L-1 and SPE recoveries in the range 63-102% from different real water matrixes, except for butylmethoxydibenzoylmethane (BM-DBM), which was not determinable in wastewater samples due to adsorption problems. The application of the method allowed reporting the levels of benzophenone-4 (BP-4) in environmental water samples for the first time, where it was identified as one of the most important in concentration among the UV filters studied, particularly in wastewater (237-1481 ng L-1).     

Simultaneous detection and identification of O-GlcNAc-modified glycoproteins using liquid chromatography-tandem mass spectrometry

Glycoproteins carrying O-linked N-acetylglucosamine (O-GlcNAc) modifications have been isolated from a wide range of organisms ranging from trypanosomes to humans. Interest in this modification is increasing as evidence accumulates that it is an abundant and transient modification that is dynamic and responsive to cellular stimuli. Concurrent advances in biological mass spectrometry (MS) have facilitated high-sensitivity protein identification by tandem MS. In this study, we show that the lability of the O-GlcNAc moiety to low-energy collision in tandem MS offers a means of distinguishing such peptides from others that are not modified. The differential between the energy required to remove the O-GlcNAc group and the energy required to fragment the peptide chain allows the O-GlcNAc group to be detected and the peptide sequence, and therefore the protein, to be identified. This technique thus allows the simultaneous detection and identification of O-GlcNAc-modified peptides, even when present at low levels in complex mixtures. The method was initially developed and validated using a synthetic O-GlcNAc-modified peptide and then applied to the detection of an extremely low abundance O-GlcNAc-modified peptide from bovine alpha-crystallin. We believe that with further development this assay system may prove to be a useful tool for the direct investigation of intracellular O-GlcNAc levels, thus providing valuable insights into the physiological role of O-GlcNAc modified proteins.     

高效液相色谱-三重四级杆质谱法测定豆制品中二甲基黄、二乙基黄

建立一种同时测定豆制品中二甲基黄、二乙基黄的高效液相色谱-三重四级杆质谱(HPLC-MS/MS)方法。对提取溶剂及色谱条件进行优化,粉碎后的样品经乙腈提取,提取液以HPLC-MS/MS测定,外标法定量。二甲基黄、二乙基黄在3 min内流出并完全分离,两者在0.05~10μg/L范围内相关系数r2均大于0.999,二甲基黄在0.5~50μg/kg的加标回收率为90.0%~93.4%,RSD为0.5%~5.1%,二乙基黄在0.5~50μg/kg水平的加标回收率在84.6%~93.8%,RSD为1.1%~4.6%,检出限两者均为0.2μg/kg。该方法操作简捷、准确度和精密度高,适用于豆制品中二甲基黄、二乙基黄的检测。     

Analysis of water contaminants and natural water samples using two-step laser mass spectrometry

The applicability of two-step laser mass spectrometry (L2MS) to the analysis of water contaminants and environmental water samples is demonstrated. First, the ionization characteristics of a selection of naphthyl and carbamate pesticides and of phenol were determined. The ion signal of all compounds increased with ionization laser pulse energy, within the investigated range (20-200 microJ). Ion yields relative to an internal standard, benz[alanthracene, reached 30% for naphthyl pesticides ionized at 225 nm and 2-8% at 266 nm. At 266 nm, similar relative ion yields were found for phenol. Carbamate pesticides showed lower relative ion yields at all wavelengths, by a factor of approximately 10-100, but higher relative ion yields, on the order of 1%, were obtained when using short (ps) laser pulses for ionization. These data allow one to estimate the detection limits of these analytes in a variety of matrixes once they are known for one of the compounds. Second, the quantitative analysis of carbaryl, phenol, and polycyclic aromatic hydrocarbons in rainwater is demonstrated. The aqueous samples were frozen to permit direct L2MS analysis of organic pollutants without tedious sample preparation. Detection limits were in the low-microgram per liter concentration range and recoveries of phenol from spiked rainwater samples were above 90%. The specific advantages are exemplified with the investigation of dynamic washout processes of atmospheric organic pollutants with a resolution of 0.01 mm of precipitation.     

Simultaneous quantification of eleven thiopurine nucleotides by liquid chromatography-tandem mass spectrometry

The prodrugs azathioprine and 6-mercaptopurine, which are well-established anticancer and immunosuppressive agents, are extensively metabolized by activating and inactivating enzymes. Whereas the 6-thioguanine nucleotides (TGN) are currently being considered as major active metabolites, methylthioinosine nucleotides seem to contribute to the cytotoxic effect as well. Thiopurine-related adverse drug reactions and thiopurine failure are frequent. Thus, therapeutic monitoring of TGN and methylthioinosine derivatives has been suggested to improve thiopurine therapy, however with limited success. To elucidate systematically underlying molecular mechanisms as potential explanation for interindividual variability of thiopurine response, we developed a novel highly specific and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous quantitation of eleven mono-, di-, and triphosphates of thioguanosine, methylthioinosine, methylthioguanosine, and thioinosine. Using stable isotope-labeled analogues as internal standards obtained by chemical synthesis, an intra- and interassay variability below 8% and an accuracy of 92% to 107% were achieved in spiked quality control samples with known standards. All eleven metabolites could be determined in red blood cells from patients with inflammatory bowel diseases and long-term azathioprine therapy. Thus, our novel method opens a new avenue for the understanding of the thiopurine metabolism by quantitation of all important thiopurine nucleotide metabolites in one run.     

Simultaneous determination of five beta-lactam antibiotics in bovine milk using liquid chromatography coupled with electrospray ionization tandem mass spectrometry

A multiresidue method for the detection of five important beta-lactam antibiotics (amoxicillin, ampicillin, cloxacillin, oxacillin, penicillin G) in fresh milk is presented that allows quantitation of the analytes well below established legislative limits. The method avoids the use of acid during the extraction procedure and entails a cleanup step over a C18 cartridge. The analytes are separated and detected by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) using a stable isotope-labeled internal standard. Mass spectral acquisition is done in the positive ion mode by applying selected reaction monitoring of two or more fragmentation transitions per analyte to provide a high degree of sensitivity and specificity. The typical recoveries for all five beta-lactams in fresh milk ranged from 76 to 94% at a fortification level of 4 microg/kg. This study also addresses common problems encountered in the stability of penicillins during sample preparation as well as the employment of postcolumn infusion of a standard compound to verify potential matrix-induced signal suppression in ESI-MS.     

Analysis of pharmaceuticals in fish using liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening method has been developed targeting 23 pharmaceuticals and 2 metabolites with differing physicochemical properties in fish tissue. Reversed-phase separation of target compounds was achieved using a C18 column and a nonlinear gradient consisting of 0.1% (v/v) formic acid and methanol. Eluted analytes were introduced into the mass analyzer using positive or negative electrospray ionization, as appropriate. A variety of extraction solvents, differing in polarity, pH, or both, were investigated in order to assess recovery of target compounds from 1-g tissue homogenates. Among 10 solvents tested, a 1:1 mixture of 0.1 M aqueous acetic acid (pH 4) and methanol was identified as optimal, resulting in extraction recoveries for 24 of 25 compounds exceeding 60%. Tissue extracts were found to influence the LC-MS/MS response for several analytes. Consequently, matrix-matched calibration standards were employed to determine analyte concentrations in environmental samples. Statistically derived method detection limits were <6 ng/g for most analytes. The method was subsequently used to screen for target analytes in fish from an effluent-dominated stream. Diphenhydramine, diltiazem, carbamazepine, and norfluoxetine were detected in 11 of 11 environmental samples at concentrations ranging from 0.11 to 5.14 ng/g.     

液相色谱-串联质谱法同时测定饲料中矮壮素和缩节胺的残留

本文采用高效液相色谱-串联质谱(HPLC-MS/MS)同时测定饲料中的矮壮素和缩节胺残留。样品先用正己烷脱除油脂,后用缓冲溶液(含0.2%甲酸-0.05mol/L乙酸铵)提取,离心上清液用乙腈沉淀净化后进行测试。结果表明:两种化合物在1.0~50.0μg/L范围内线性关系良好;定量限(S/N=10)矮壮素为0.32μg/L,缩节胺为0.45μg/L;加标回收率为91.7%~94.3%;相对标准偏差3.9%~6.1%;实测有30%的样品中含有矮壮素或缩节胺,含量范围为:矮壮素11.2μg/kg-78.4μg/kg;缩节胺9.7μg/kg-126.6μg/kg。该方法简便、快速、灵敏和准确,适合饲料中这两种农药残留的快速检测和定量分析。     

固相萃取-高效液相色谱-荧光法测定人体尿液中单胺类神经递质

建立一种快速、准确测定人体尿液中肾上腺素、去甲肾上腺素、多巴胺及5-羟色胺4种单胺类神经递质的方法。尿液样品以Waters Oasis WCX固相萃取柱富集,依次用2 m L 20 mmol/L乙酸铵-甲醇溶液、2 m L甲醇淋洗杂质,最后用5 m L含2%甲酸的乙腈水溶液(85∶15,ν∶ν)提取被分析物。经Agilent C18色谱柱(250 mm×4.6 mm,5μm)分离,以甲醇与乙酸钠溶液的不同配比设置流动相梯度,在荧光检测激发波长280 nm,发射波长340 nm条件下,测定人体尿液中4种单胺类神经递质的含量。结果表明:4种单胺类神经递质的回收率为92.2%~104.8%,相对偏差为1.6%~3.1%,检出限为0.002~0.05μg/m L。该方法稳定、快速、简便,能满足人体尿液中多种单胺类神经递质的含量测定。     

Hydrophilic interaction liquid chromatography-tandem mass spectrometry determination of estrogen conjugates in human urine

We report a hydrophilic interaction liquid chromatography (HILIC) separation with tandem mass spectrometry (MS) detection method for analysis of seven urinary estrogen conjugates. HILIC separation employing a mobile phase with high organic solvent content resulted in enhanced electrospray ionization efficiency and MS sensitivity compared with reversed-phase (RP) LC-MS methods. Solid-phase extraction (SPE) was used to further improve the limit of detection and to eliminate interferences for the analysis of urine samples. No hydrolysis or derivatization was required in the sample pretreatment. This SPE/HILIC-MS/MS method provided limits of quantification (LOQs at S/N = 10) for the seven conjugates ranging from 2 to 1000 pg/mL with only 1 mL of urine sample, representing an improvement of 1 order of magnitude over the RPLC tandem MS methods previously reported. This method provided a linear dynamic range of 3 orders of magnitude, recovery of 92-109%, intraday accuracy of 84-109%, intraday precision of 1-14%, interday accuracy of 80-111%, and interday precision of 1-22%. We have successfully applied this technique to determine the seven estrogen conjugates in urine samples of a pregnant woman and found unique concentration changes of six estrogen conjugates at different stages of pregnancy while the concentration of estriol-3-glucuronide (E3-3G) remained constant. We further studied the profiles of individual estrogen conjugates in breast cancer patients before and after treatment and found patient-dependent effects of aromatase inhibitor treatment on estrogen phase-II metabolism, which have not been reported previously. This study demonstrates the potential clinical application of the HILIC-MS/MS technique for sensitive monitoring of the changes of urinary estrogen conjugates in a clinical setting.