The Detection of THCA Using 2-Dimensional Gas Chromatography-Tandem Mass Spectrometry in Human Fingernail Clippings: Method Validation and Comparison with Head Hair

Marijuana use as well as abuse is a significant public health and public safety concern in the United States and using hair to identify marijuana users and abusers has been gaining acceptance in a number of venues including workplace, court ordered, and substance abuse treatment monitoring. After the presentation of a fully validated 2-dimensional gas chromatography-tandem mass spectrometry method for the detection of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCA), the chief metabolite of the main psychoactive compound in marijuana, Δ9-tetrahydrocannabinol (THC), we evaluated the usefulness of fingernail clippings as an alternative specimen type to hair by the analysis of a set of 60 matched pairs of head hair and fingernail clippings. The limit of detection was 10 fg/mg, the limit of quantitation was 20 fg/mg, and the assay was linear from 20 fg/mg to 500 fg/mg. The intra- and inter-assay imprecision and bias studies at 4 different concentrations (50, 100, 500, and 1000 fg/mg) were acceptable where all % Target observations were within 16% of their expected concentrations and all %CV calculations were less than 13.5%. THCA was detectable in more fingernail specimens (53.3%) than hair specimens (46.7%) and the mean concentrations in nails were on average 4.9 times higher than in hair (1813 fg/mg and 364 fg/mg, respectively). The THCA concentrations in hair and nail were strongly associated (r = 0.974, P < 0.01, n = 60) and the association was significant. The study demonstrated that fingernail clippings are a suitable alternative specimen type to hair to monitor for marijuana use and abuse.

Determination of 8 Diuretics and Probenecid in Human Urine by Gas Chromatography-Mass Spectrometry: Confirmation Procedure

A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in human urine using gas-chromatography with mass spectrometric detection is described. The extraction of the substances as function of the nature of organic solvent, mixing time and pH of aqueous phase was studied. The tandem mass spectrometry was used to increase selectivity of diuretics determination due to elimination of background interferences. Fragmentation reactions were studied for each compound and their collision energies were optimized to obtain the best selectivity. The results of method’s validation demonstrate its suitability in routine analysis for confirmation purposes.

Trace-Level Analysis of Hexavalent Chromium in Lake Sediment Samples Using Ion Chromatography Tandem Mass Spectrometry

The analysis of hexavalent chromium, Cr(VI), in soil and sediment samples has been predominantly carried out in materials containing elevated levels. Reliable analysis of trace-level of Cr(VI) in sediment samples remains challenging. Cr(VI) analyses with multipoint calibration and speciated isotope dilution (SID) adapted from U.S. EPA method 6800 were used to measure lower-level Cr(VI) on an ion chromatograph coupled with a tandem mass spectrometer (IC-MS/MS). Lake sediment samples were collected from various locations in Northern Ontario and Cr(VI) was extracted using both alkaline digestion and ethylene diaminetetraacetic acid (EDTA) extraction. Certified reference materials were extracted and analyzed by IC-MS/MS and UV-VIS detection. The SID-MS approach allowed for the quantification of Cr(VI) in samples with concentration levels below 0.5 μg.g-1 wet weight.

Studies on Fragmentation Pathways of N-Ethoxy(phenyl) phosphoryl Amino Acids by Electrospray Ionization Tandem Mass Spectrometry

The positive and negative ESI-MS/MS spectra of N-ethoxy（phenyl） phosphoryl amino acids（EPP-AA） were investigated by electrospray ionization（ESI） ion trap mass spectrometry. The fragmentation pathways of [ M ＋ Na]^＋ and [ M - H]^- ions are proposed and rationalized. The observation may have some potential applications in the interpretation of the MS/MS spectra of novel N-phosphoryl compounds. The complexity of MS/MS spectra of EPP-AA [ M ＋ Na]^＋ ions is decreased compared with that of N-dialkyloxyphosphoryl amino acid. Therefore, the new phosphonamidate method may be considered one of the superior methods that can be used in sequencing peptides and proteins extensively.

Screening and Identifying of Nephrotoxic Compounds in Lithospermum erythrorhizon Using Live-cell Fluorescence Imaging and Liquid Chromatography Coupled with Tandem Mass Spectrometry

In order to identify the potential nephrotoxic compounds in traditional Chinese medicine Lithospermum erythrorhizon,it was separated into serial fractions according to their polarities.An in vitro method was utilized to determine the nephrotoxicity of these fractions with the help of fluorescence image analysis.As a result,the primary fraction A05 and its secondary fractions C06 ＂C09 and C12 ＂C14 were found to have significant toxicity to LLC-PK1 cell line,as determined by the survive rate less than 20% after they were treated with these fractions.These potential nephrotoxic fractions were further analyzed by multistage and high resolution mass spectrometry.The main compounds in these fractions were tentatively identified to be acetylshikonin,isobutyrylshikonin,β,β＇-dimethyla-cryloylshikonin,and isovalerylshikonin,which may bring nephrotoxicity.

基于UFLC-QTrap-MS/MS结合多元统计分析的不同产地、不同部位乌药中核苷和氨基酸类成分分析

本研究建立了一种超快速液相色谱-三重四极杆/线性离子阱-串联质谱(UFLC-QTrap-MS/MS)同时测定乌药中11种核苷类和14种氨基酸类成分的分析方法,并结合多元统计分析比较不同产地、不同部位乌药的质量。采用Waters XBridge Amide色谱柱(2.1 mm×100 mm×3.5μm),以0.2%甲酸水溶液(A)-0.2%甲酸乙腈溶液(B)为流动相进行梯度洗脱;在电喷雾正离子模式下,以多反应监测(MRM)进行质谱检测;基于各成分的质量浓度,用方差分析(ANOVA)、主成分分析(PCA)、正交偏最小二乘法判别分析(OPLS-DA)、层次聚类分析(HCA)、逼近理想解排序法(TOPSIS)以及灰色关联度分析(GRA),对不同产地、不同部位乌药样品进行综合评价。结果表明,所测成分在一定浓度范围内具有良好的线性关系,相关系数均大于0.9924;精密度、重复性、稳定性良好,平均加样回收率为94.86%~106.47%,相对标准偏差(RSD)均小于4.55%。不同产地、不同部位乌药样品间存在一定的差异,HCA和PCA 2种方法均将样品分为3类。OPLS-DA模型分析通过VIP值共筛选得到6个差异性化合物,分别为尿苷、丙氨酸、胞嘧啶、黄嘌呤、腺嘌呤、鸟嘌呤。该方法简便、灵敏度高、重现性好,可用于乌药中核苷和氨基酸类成分的同时测定,为药材质量评价和综合利用提供方法参考。

基于UHPLC-QTRAP-MS/MS的淫羊藿中多元活性成分动态累积的分析与评价

建立了超高效液相色谱-三重四极杆线性离子阱串联质谱(UHPLC-QTRAP-MS/MS)同时测定淫羊藿中黄酮类、生物碱类、酚酸类、氨基酸类及核苷类共50种活性成分的分析方法,并对其多元活性成分的动态累积进行分析与评价。采用Agilent ZORBAX Extend-C18(2.1 mm×100 mm,1.8μm)色谱柱,以水(含0.2%甲酸)-乙腈为流动相梯度分离,流速0.3 mL/min,柱温40℃。质谱配备电喷雾离子源,在正、负离子模式下采用多反应监测模式(MRM)进行测定;采用单因素实验及响应面法优化样品制备条件,灰色关联度分析(GRA)对不同采收期淫羊藿样品进行分析与评价。结果显示,50种目标成分在一定范围内线性关系良好(r2≥0.9990),精密度、重复性和稳定性良好,平均加标回收率为94.5%~107%,相对标准偏差(RSD)均小于5.0%。淫羊藿中多元活性成分累积量在7月中旬出现峰值,不同类别成分累积规律具有一定差异性。6月下旬至7月下旬所采收的淫羊藿药材综合质量较好,与当地传统采收期基本吻合。该研究所构建的方法准确、可靠,可为探究淫羊藿中多元活性成分动态累积规律及确定适宜采收期提供依据,同时也箭叶淫羊藿药材质量的综合评价和整体控制提供方法参考。

Fragmentation study of two brassinolides by ion trap tandem mass spectrometry

The fragmentation pathways of two isomers of brassinosteroids,28-homobrassinolide(28-h-BL)and 28-epihomobrassinolide(28-eh-BL),have been investigated by tandem mass spectrometry(MSn,n=1,2,3,4)with the electrospray ionization(ESI) source.The ESI mass spectrometric fragmentation pathways of protonated 28-h-BL and 28-eh-BL were comprehensively elucidated,and the principles revealed in this investigation could potentially be used to identify and distinguish brassinosteroids and their isomers.

自主研制四极杆-线形离子阱质谱仪测定血清中甲氨蝶呤

本研究基于自主研制的QLIT-6610MD液相色谱-四极杆-线形离子阱-质谱联用仪,建立了准确测量血清中甲氨蝶呤的同位素稀释质谱法。采用甲醇沉淀血清样品的蛋白后测定上清液。通过基质匹配标准曲线定量,在10~5000μg/L浓度范围内,甲氨蝶呤的线性系数R^(2)>0.9990,定量限为10μg/L,质控品精密度优于6.94%,血清样本添加回收率为86.39%~97.84%,变异系数(CV)≤8.04%。应用QLIT-6610MD与AB QTRAP 6500+液相色谱-质谱联用仪同时测定70例临床血清样本,并采用Pearson系数与BLand-ALtman法进行比较。结果表明,2台仪器所测结果一致,QLIT-6610MD可达到三重四极杆质谱仪定量测定血清中甲氨蝶呤的水平,能够满足临床诊断需求,为临床质谱分析提供了一种新的国产仪器选择。此外,本研究还初步探讨了多级碎裂技术(MSn)测定血清中甲氨蝶呤的可能性,为后续研究奠定基础。

A Systematical Analysis of Tryptic Peptide Identification with Reverse Phase Liquid Chromatography and Electrospray Ion Trap Mass Spectrometry

In this study we systematically analyzed the elution condition of tryptic peptides and the characteristics of identi?ed peptides in reverse phase liquid chromatogra- phy and electrospray tandem mass spectrometry (RPLC-MS/MS) analysis. Fol- lowing protein digestion with trypsin, the peptide mixture was analyzed by on-line RPLC-MS/MS. Bovine serum albumin (BSA) was used to optimize acetonitrile (ACN) elution gradient for tryptic peptides, and Cytochrome C was used to retest the gradient and the sensitivity of LC-MS/MS. The characteristics of identi?ed peptides were also analyzed. In our experiments, the suitable ACN gradient is 5% to 30% for tryptic peptide elution and the sensitivity of LC-MS/MS is 50 fmol. Analysis of the tryptic peptides demonstrated that longer (more than 10 amino acids) and multi-charge state (+2, +3) peptides are likely to be identi?ed, and the hydropathicity of the peptides might not be related to whether it is more likely to be identi?ed or not. The number of identi?ed peptides for a protein might be used to estimate its loading amount under the same sample background. Moreover, in this study the identi?ed peptides present three types of redundancy, namely iden- ti?cation, charge, and sequence redundancy, which may repress low abundance protein identi?cation.

基质溶剂校正结合高温离子源GC-MS/MS同时分析烟气中16种多环芳烃

本研究建立了高温离子源气相色谱-三重四极杆串联质谱(GC-MS/MS)法结合基质溶剂校正,使用样品萃取溶液直接进样,同时测定卷烟主流烟气中16种多环芳烃(PAHs)。考察了常温和高温离子源对目标物响应情况的影响,探究基质溶剂制备方法及基质效应对目标物定量结果的影响,分析市售不同圆周卷烟烟气的释放分布情况。结果表明,16种PAHs的定量工作曲线在各自线性范围内的相关系数R2为0.996 4~0.999 8,检出限为0.29~1.48 ng/支,定量限为0.95~4.94 ng/支,在低、中、高3个不同添加水平下的平均回收率为87.71%~123.26%,精密度为1.58%~9.45%。通过分析参比卷烟3R4F,该方法的检测结果与文献报道结果无明显差异。采用该方法检测市售58个品牌卷烟样品中的PAHs,总释放量为742.76~1 505.99 ng/支,并随卷烟焦油量减少而下降。该方法具有前处理简便,准确及重复性好的优点,适用于卷烟主流烟气中痕量PAHs的定量分析。

LTQ-Orbitrap组合式高分辨质谱法快速筛查毛发中7种毒品及代谢物

采用超高压液相色谱-二维线性离子阱结合静电场轨道阱组合式高分辨质谱联用技术(Accela U HPLC/LTQ Orbitrap XL),建立了人毛发中吗啡、O^6-单乙酰吗啡、可待因、乙酰可待因、氯胺酮、去甲氯胺酮和美沙酮毒品及代谢物快速筛查方法。取毛发样品经表层清洗后冷冻研磨粉碎,置于硼酸盐缓冲液(pH 9.2)中超声90 min,离心取上清液,用Oasis HLB柱固相萃取制备。通过静电场轨道阱全扫描得到毒品及其代谢物的精确相对分子质量,同时进行7种毒品及其代谢物的快速筛查。高分辨率质谱可有效去除毛发基质干扰,毒品及其代谢物筛查检出限在0.001～0.02 ng/mg,在0.05～50 ng/mg范围内存在良好线性关系(r>0.9975);本方法平均加标回收率为76.1%～109.6%;日内及日间精密度RSD≤14.9%。本方法灵敏度高,样品制备简便,适用于常见毒品的快速筛查。

定量磷酸化蛋白质组解析17β-雌二醇致死效应的细胞调控过程

17β-雌二醇(E2)是人体内一种重要的内分泌激素,在生理浓度下(0.2~1.0 nmol/L)对生殖系统、乳腺等靶器官的生长发育起着重要的调节作用。但很多研究表明,高剂量(μmol/L~mmol/L)的E2能够诱导肿瘤组织消退和细胞凋亡,其具体调控机制尚不明确。本工作聚焦于高剂量(μmol/L)的E2致死效应,首先分析了μmol/L水平的E2对HeLa细胞表型的影响,发现在1~10μmol/L下E2以浓度依赖的形式抑制HeLa细胞增殖,并诱导HeLa细胞发生死亡,其中,用5μmol/L E2处理2天后可使约74%的HeLa细胞增殖受到抑制,并引起约50%的HeLa细胞死亡。在此基础上,为了探究高剂量E2诱导细胞死亡的内在调控过程,将基于固相萃取(SPE)的固定化钛离子亲和色谱技术(Ti 4+-IMAC)与基于数据非依赖采集模式(DIA)的蛋白质组定量技术结合,用于筛选HeLa细胞内参与高剂量(μmol/L)E2致死效应调控过程的磷酸化位点。最终,在5μmol/L E2和二甲基亚砜(DMSO)处理的HeLa细胞中共鉴定到超过10000个磷酸化位点;t检验分析发现,在E2处理后,有924个磷酸化位点(对应599个蛋白质)的丰度发生了显著变化(显著性水平(p)<0.01,|log 2(倍数变化)|≥1),推测其可能参与调控E2致死效应过程。此外,有453个磷酸化位点(对应325个蛋白质)仅单独发生在E2或DMSO处理后的HeLa细胞样品中,表明这些磷酸化位点在E2处理后发生了磷酸化或去磷酸化,也可能参与E2致死效应的调控过程。分别对以上两种方式筛选的E2调控的磷酸化蛋白质进行富集分析,发现这些磷酸化蛋白质主要参与细胞分裂、核糖体/核质转运、信使核糖核酸(mRNA)加工/剪接及转录等过程,表明高剂量的E2可能通过调控核糖体及mRNA加工等过程影响蛋白质转录,进而诱导细胞发生死亡。此外,我们发现表皮生长因子受体(EGFR)和丝裂原活化蛋白激酶(MAPK)家族蛋白(包括MAPK1、MAPK4和MAPK14)上多个磷酸化位点的修饰水平在高剂量E2处理后发生了明显变化,表明EGFR和MAPK信号通路可能在雌激素诱导的细胞死亡中起着重要调控作用。本实验得到的磷酸化蛋白质组定量结果有助于进一步了解高剂量E2的内在调控过程,为后续解析高剂量E2的作用机制及疾病的治疗提供了参考。

Identification of phosphorylation sites of proteins by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry

The phosphorylation sites of two phosphorylated proteins, bovine β-casein and myelin basic protein (MBP), were identified by high performance liquid chromatography-electrospray ionization-quadrupole ion trap mass spectrometry (HPLC-ESI-QITMS). The tryptic digest of each protein was separated by HPLC, the molecular weight of each peptide was determined by ESI-QITMS on line, and MS/MS spectrum of each peptide was simultaneously obtained by the combination of collision-induced desorption (CID) technique and tandem mass spectrometry (MS/MS) of QITMS. The phosphorylated peptide was identified by looking into whether the difference between the observed and predicted molecular weights of a peptide is 80 u or its integral multiple. Then the phosphorylation site was identified through manual interpretation of the MS/MS spectrum of the phosphorylated peptide or automatic SEQUEST data base-searching.

混合型离子交换反相吸附固相萃取-超高效液相色谱-三重四极杆质谱法测定水中23种非甾体抗炎药的残留

非甾体抗炎药(NSAIDs)作为一种新型有机污染物,在环境水体中普遍检出,对生态系统及人体健康造成潜在的威胁,开发准确、可靠的测定水中痕量非甾体抗炎药的检测方法至为重要.本文采用Oasis MCX固相萃取柱对水样进行富集,建立测定水中23种非甾体抗炎药的超高效液相色谱-三重四极杆质谱分析方法.采用酸性条件(pH=4)萃取水样,上样的流速为2 mL·min^(−1),用4 mL甲醇-4 mL5%氨水甲醇进行洗脱,浓缩定容后用ACQUITY UPLCTM BEH C18柱(2.1 mm×100 mm,1.7μm),以2 mmol·L^(−1)乙酸铵+0.05%(V/V)甲酸水溶液-乙腈作为流动相进行梯度洗脱,多反应选择离子监测(MRM)模式进行检测,内标法定量.23种NSAIDs在相关线性范围内线性良好(r=0.9951—0.9992),回收率为80.2%—120%,相对标准偏差为0.4%—12.5%,方法检出限为0.20—4.84 ng·L^(−1).将该方法应用于10份地表水的检测,结果显示有10种NSAIDs检出,质量浓度在ND—83.5 ng·L^(−1)之间.该方法简单、灵敏、高效,可应用于环境水体中NSAIDs的检测.

UHPLC-LTQ-Orbitrap HRMS法结合特征裂解途径分析鉴定薄荷水提物中4种类群化学成分

采用超高效液相色谱-线性离子阱-串联静电轨道阱高分辨质谱(UHPLC-LTQ-Orbitrap HRMS)法对薄荷水提物中4种类群化学成分进行分析鉴定。选取Acquity UPLC~BEH C18色谱柱(2.1mm×100mm×1.7μm),以乙腈-0.1%甲酸水溶液为流动相,流速0.30mL/min,梯度洗脱分析。根据高分辨质谱提供的准分子离子峰和碎片离子信息,获取目标化合物的相对分子质量和结构信息,并结合保留时间、对照品分析、参考文献数据和ClogP值等相关信息,鉴定了85种化学成分,包括38种黄酮、16种酚酸、7种苯丙素和24种萜类。结果表明,采用UHPLC-LTQ-Orbitrap HRMS技术能够提高中药化学成分的分析效率,该方法可为合理开发薄荷的药用和食用价值奠定化学基础。

基于UHPLC-LTQ/Orbitrap MS法的苦荬菜内酯Z和11,13α-二氢苦荬菜内酯Z的大鼠肝微粒体体外代谢产物鉴定

苦荬菜内酯Z和11,13α-二氢苦荬菜内酯Z是苦碟子(Ixeris sonchifolia(Bunge)Hance)中2种重要的倍半萜内酯类成分。为研究它们在大鼠肝微粒体中的代谢产物,采用Waters Acquity UPLC BEH C18色谱柱(2.1mm×50mm×1.7μm)分离,以0.1%甲酸水(A)-乙腈(B)为流动相进行梯度洗脱,采用高效液相色谱-线性离子阱静电轨道场质谱(UHPLC-LTQ/Orbitrap MS)技术,在ESI负离子模式下分析样品。筛选出18个化合物(包括苦荬菜内酯Z和11,13α-二氢苦荬菜内酯Z,及其16个代谢产物),并对其中15个代谢产物进行结构鉴定。结果表明,苦荬菜内酯Z和11,13α-二氢苦荬菜内酯Z经大鼠肝微粒体主要发生了羟基化、加氢和脱氢的Ⅰ相代谢反应。该结果初步阐明了苦荬菜内酯Z和11,13α-二氢苦荬菜内酯Z在大鼠肝微粒体中的代谢规律,可为新药、毒理学研究提供支持。

UPLC-LTQ-Orbitrap-MS快速识别驱虫斑鸠菊中多酚类化合物

目的:对驱虫斑鸠菊乙醇提取物中的化学成分进行分析鉴定。方法:采用超高效液相色谱-线性离子阱/静电场轨道阱组合式高分辨质谱(UPLC-LTQ-Orbitrap-MS)联用技术,总结驱虫斑鸠菊中黄酮类和咖啡酰奎宁酸类化合物的质谱裂解规律,建立其乙醇提取物中多酚类成分的快速识别方法,并对其中的化学成分进行识别。结果:从其乙醇提取物中初步鉴定出43种多酚类化合物,其中包括30种黄酮类成分和13种酚酸类成分。结论:有26种化合物是首次在驱虫斑鸠菊中发现。

Q TRAP在药物代谢研究中的应用

三重四极杆质谱仪在定量分析方面较优,而离子阱质谱仪则在定性分析方面较优。Q TRAP质谱仪将三重四极杆质谱仪和离子阱质谱仪的功能以一种新的方式结合在一起,既保留了串联四极杆质谱仪的优点,如母离子扫描、中性丢失扫描、选择反应监测的功能,又克服了传统3D离子阱质谱仪诸如低质量截止点(1/3效应)等缺点,是一台集定性与定量功能于一体的质谱仪。该文介绍了QTRAP四极杆-线性离子阱质谱仪的基本原理和分析策略,并简述其在药物代谢研究方面的应用。

高效液相色谱-三重四极杆/复合线性离子阱质谱法同时测定液态发酵食品中14种生物胺及其代谢物

目的基于高效液相色谱-三重四极杆/复合线性离子阱质谱法(high performance liquid chromatography-triple quadrupole/composite linear ion trap mass spectrometry,HPLC-QTRAP MS)建立同时测定液态发酵食品中14中生物胺及其代谢物的分析方法。方法采用Waters Atlantis Premier BEH Z-HILIC色谱柱(100mm×2.1mm,1.7μm),以0.025%(V/V)甲酸水和0.1%(V/V)甲酸乙腈进行梯度洗脱,电喷雾离子源(electrospray ionization,ESI)正离子模式、多反应监测(multiple reaction monitoring,MRM)离子扫描模式、信息依赖性采集(information dependent acquisition,IDA)、增强子离子扫描(enhanced ion scanning,EPI)和EPI谱库搜索的复合模式进行测定。结果在0.05~200.00μg/L质量浓度范围内,14种生物胺及其代谢物的线性关系良好,相关系数均大于0.99;方法检出限(S/N=3)为0.15~6.00μg/L;在不同添加质量浓度(2.0、10.0、50.0μg/L)下,其回收率为75.2%~107.9%,相对标准偏差在1.98%~9.07%之间。结论该方法具有操作简便、快速、准确、灵敏等优点,可满足液态类发酵食品中14种生物胺的定性定量分析需要,为液态发酵类食品中生物胺的检测分析奠定基础。