HPLC-DAD和LC-MS/MS法对各种芦荟样品中蒽醌类成分的分析研究

采用HPLC-DAD和LC-MS／MS对各种芦荟样品中蒽醌类成分进行鉴定,在此基础上建立了同时测定各种芦荟样品中芦荟苷与芦荟大黄素含量的方法。采用Nucleodur-silica色谱柱（250mm＊4．6mm,5μm）,流动相A为甲醇-醋酸（500：1．70）,B为水．醋酸（500：1．70）,梯度洗脱,流速1．0mL／min,DAD扫描波长范围为190～370nm,紫外检测波长为254和356nm。质谱离子源为ESI,采用全扫描一级质谱和选择离子全扫描二级质谱两种方式同时测定。结果表明：各种芦荟样品中主要的蒽醌类成分为芦荟苷A、B与芦荟大黄素,未检测到大黄素、大黄酸、大黄素甲醚、大黄酚;芦荟干粉中所含的芦荟苷含量最高。该法准确、可靠、重现性好,可行性高。     

Identification of quercetin glucuronides in human plasma by high-performance liquid chromatography–tandem mass spectrometry

After intake of food or herbal medicinal products containing quercetin glycosides, the systemic availability of the genuine glycoside, as well as the systemic occurrence of the aglycone or conjugates of this polyphenol has been a matter of dispute. Consequently, we designed this study to develop a reliable method for determination of quercetin and its metabolites. Following consumption of fried onions five different glucuronides of quercetin could be identified in human plasma samples by means of HPLC–UV–MS/MS. Selective determination of the target compounds was achieved by simultaneous UV (254 nm) and MS/MS detection with selected reaction monitoring experiments using positive mode electrospray ionisation. In contrast, neither the free flavonol nor the genuine glycoside could be detected in plasma. Identification of the quercetin glucuronides detected in vivo was confirmed by comparison with authentic reference compounds synthesised enzymatically using glucuronyl transferase from rabbit liver.     

Tandem mass spectrometric assay of succinylacetone in urine for the diagnosis of hepatorenal tyrosinemia

We describe an isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of succinylacetone (SA) in urine for the diagnosis of hepatorenal tyrosinemia (HT1). The method used 15N-labeled 5(3)-methyl-3(5)-isoxazole propionic acid as internal standard. Urine samples were oximated with hydroxylamine hydrochloride at 80 degrees C, extracted by solvent-solvent extraction, and followed by derivatization of the butyl ester. The butylated isoxazole derivatives of SA and its internal standard were detected and quantified using positive ion electrospray LC-MS/MS with selected reaction monitoring. The turnaround time between injections was 10 min. Calibration curves were linear over the range of 0.0633-63.3 micromol/L. The intra- and interday assay variations were less than 7%. Mean recoveries of SA at three different concentrations ranged from 96 to 109%. During the course of this study, we identified 12 new patients with HT1 and applied this method to follow up the treatment of 4 of these patients as well as previously diagnosed HT1 patients.     

LC-MS/MS法测定人血浆中伊伐布雷定浓度及药动学

目的：建立人血浆中伊伐布雷定的液相色谱-质谱-质谱联用测定方法,研究健康人体药代动力学。方法：以地西泮为内标物,采用液相色谱-质谱-质谱联用法,电喷雾电离源选择性正离子峰检测。测30名健康志愿者单剂量口服盐酸伊伐布雷定片的体内血药浓度,获得药动学参数。结果：伊伐布雷定在0.101-101 ng·mL-1浓度范围内呈良好的线性关系（r=0.998）,最低检测浓度为0.101 ng·mL-1。高、中、低浓度的方法提取回收率分别为93.2%、86.6%、87.5%,日内、日间精密度RSD均小于15%。结论：LC-MS/MS方法灵敏度高,专属性强,准确,简便,适用于盐酸伊伐布雷定片的人体药代动力学研究。     

Liquid chromatography-tandem mass spectrometry analysis of urinary fluticasone propionate-17beta-carboxylic acid for monitoring compliance with inhaled-fluticasone propionate therapy

Background

Inhaled corticosteroids including fluticasone propionate (FP) are the most effective treatment for persistent-asthma. Noncompliance ranging from 20% to 80% of treated patients is associated with substantial health care costs, morbidity and fatalities. A noninvasive test to assess FP treatment compliance is needed. The major metabolite of FP is FP-17beta-carboxylic acid (FP17βCA) and is excreted in urine. This study demonstrates the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay to measure FP17βCA in urine and evaluation of FP17βCA urinary elimination.

Experimental

Fluorometholone was used as the internal standard. After acetonitrile precipitation, samples were extracted with dichloromethane, washed and dried. Reconstituted extract (60 μL) was subjected to reversed-phase chromatography and positive-ion mode LC-MS/MS analysis. Assay precision, linearity, recovery and sample stability were determined. Elimination evaluation included measurement of FP17βCA in urine collected daily from human subjects before (day 1), during treatment (days 2-5; dose FP-110 μg 2 puffs/day), and following cessation of FP therapy (days 6-14; n = 4).

Results

Linear range of the FP17βCA assay was 10.3-9510 pg/mL. Limit of quantitation (LOQ) was 10.3 pg/mL and recovery ranged from 85.8% to 111.9%. Inter-assay CVs were 7.4-12.0% for FP17βCA concentrations of 11.1-5117 pg/mL. Urine FP17βCA was absent in subjects prior to FP therapy, detectable (180-1991 ng FP17βCA/g creatinine) throughout the dosing period and reached below the LOQ at 6 days after therapy cessation.

Conclusions

Measurement of FP17βCA by LC-MS/MS has acceptable analytical performance for clinical use. These data support the clinical utility of measuring FP17βCA in urine to monitor patient compliance with FP therapy.     

Analysis of the site-specific N-glycosylation of beta1,6 N-acetylglucosaminyltransferase V

N-acetylglucosaminyltransferase V (GnT-V) catalyzes the addition of a beta1,6-linked GlcNAc to the alpha1,6 mannose of the trimannosyl core to form tri- and tetraantennary N-glycans and contains six putative N-linked sites. We used mass spectrometry techniques combined with exoglycosidase digestions of recombinant human GnT-V expressed in CHO cells, to identify its N-glycan structures and their sites of expression. Release of N-glycans by PNGase F treatment, followed by analysis of the permethylated glycans using MALDI-TOF MS, indicated a range of complex glycans from bi- to tetraantennary species. Mapping of the glycosylation sites was performed by enriching for trypsin-digested glycopeptides, followed by analysis of each fraction with Q-TOF MS. Predicted tryptic glycopeptides were identified by comparisons of theoretical masses of peptides with various glycan masses to the masses of the glycopeptides determined experimentally. Of the three putative glycosylation sites in the catalytic region, peptides containing sites Asn 334, 433, and 447 were identified as being N-glycosylated. Asn 334 is glycosylated with only a biantennary structure with one or two terminating sialic acids. Sites Asn 433 and 447 both contain structures that range from biantennary with two sialic acids to tetraantennary terminating with four sialic acids. The predominant glycan species found on both of these sites is a triantennary with three sialic acids. The appearance of only biantennary glycans at site Asn 433, coupled with the appearance of more highly branched structures at Asn 334 and 447, demonstrates that biantennary acceptors present at different sites on the same protein during biosynthesis can differ in their accessibility for branching by GnT-V.     

LC-MS/MS 法测定人血浆中伊伐布雷定浓度及药动学

目的:建立人血浆中伊伐布雷定的液相色谱-质谱-质谱联用测定方法,研究健康人体药代动力学.方法:以地西泮为内标物,采用液相色谱-质谱-质谱联用法,电喷雾电离源选择性正离子峰检测.测30名健康志愿者单剂量口服盐酸伊伐布雷定片的体内血药浓度,获得药动学参数.结果:伊伐布雷定在0.101-101 ng·mL-1浓度范围内呈良好的线性关系(r=0.998),最低检测浓度为0.101 ng·mL-1.高、中、低浓度的方法提取回收率分别为93.2%、86.6%、87.5%,日内、日间精密度RSD均小于15%.结论:LC-MS/MS方法灵敏度高,专属性强,准确,简便,适用于盐酸伊伐布雷定片的人体药代动力学研究.     

植物凝集素串联法富集纯化血清多个亚糖蛋白质组

蛋白质糖基化修饰是哺乳动物中最为常见的一种翻译后修饰,蛋白质的寡糖侧链具有重要的生物学意义,如蛋白质分子间及细胞间相互作用、识别、肿瘤侵袭与转移等.本实验应用寡甘露糖型亲合层析柱、唾液酸型层析柱和O-连接糖蛋白亲合层析柱从血清中序列性提取寡甘露糖型、唾液酸型的N-连接糖蛋白及O-连接的糖蛋白,一维和二维电泳图谱显示血清...     

LogViewer: A Software Tool to Visualize Quality Control Parameters to Optimize Proteomics Experiments using Orbitrap and LTQ-FT Mass Spectrometers

Visualization tools that allow both optimization of instrument''s parameters for data acquisition and specific quality control (QC) for a given sample prior to time-consuming database searches have been scarce until recently and are currently still not freely available. To address this need, we have developed the visualization tool LogViewer, which uses diagnostic data from the RAW files of the Thermo Orbitrap and linear trap quadrupole-Fourier transform (LTQ-FT) mass spectrometers to monitor relevant metrics. To summarize and visualize the performance on our test samples, log files from RawXtract are imported and displayed. LogViewer is a visualization tool that allows a specific and fast QC for a given sample without time-consuming database searches. QC metrics displayed include: mass spectrometry (MS) ion-injection time histograms, MS ion-injection time versus retention time, MS² ion-injection time histograms, MS² ion-injection time versus retention time, dependent scan histograms, charge-state histograms, mass-to-charge ratio (M/Z) distributions, M/Z histograms, mass histograms, mass distribution, summary, repeat analyses, Raw MS, and Raw MS². Systematically optimizing all metrics allowed us to increase our protein identification rates from 600 proteins to routinely determine up to 1400 proteins in any 160-min analysis of a complex mixture (e.g., yeast lysate) at a false discovery rate of <1%. Visualization tools, such as LogViewer, make QC of complex liquid chromotography (LC)-MS and LC-MS/MS data and optimization of the instrument''s parameters accessible to users.     

LC-MS/MS检测癫痫患者神经递质类氨基酸

目的：建立液相色谱串联质谱同位素内标法检测神经递质类氨基酸并用于癫痫患者临床评价。方法：选用AAA-C18柱色谱柱,以乙腈水（含有0.01%七氟丁酸、0.1%甲酸）为流动相,采用梯度洗脱进行分离,血浆样品用iTRAQ-115衍生化试剂处理后,加入iTRAQ-114衍生化的氨基酸内标并进样,选用3200QTRAP型质谱仪的多重反应监测（MRM）扫描方式进行检测。疾病组与健康组的统计采用t检验和主成份分析。结果：疾病组和健康组氨基酸测定结果显示：Trp、GABA两组间没有显著性差异（P〉0.05）,Arg、Gly、Ser、Tau、Asp、Glu、EtN、两组间有显著性差异（P〈0.05）,通过PCA分析显示,疾病组与健康组之间差异明显,Asp、Glu、Ser等是引起差异的主要氨基酸。结论：试验方法灵敏、专属性强,并初步的用于癫痫患者体内氨基酸评价。     

Development of an LC-MS/MS method for the simultaneous quantification of aripiprazole and dehydroaripiprazole in human plasma

A selective, sensitive, and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of aripiprazole and its active metabolite dehydroaripiprazole in human plasma has been developed using papaverine as internal standard (IS). LC-MS/MS analysis was carried out on a Finnigan LC-TSQ Quantum mass spectrometer using positive ion electrospray ionization (ESI⁺) and selected reaction monitoring (SRM). The assays for aripiprazole and dehydroaripiprazole were linear over the ranges of 0.1 to 600 ng/ml and 0.01 to 60 ng/ml, respectively. The average recoveries in plasma samples both were better than 85%. The intra- and interrun precision and accuracy values were found to be within the assay variability criteria limits according to the US Food and Drug Administration guidelines. The developed method was proved to be suitable for use in a clinical pharmacokinetic study after a single oral administration of a 5-mg aripiprazole tablet in healthy Chinese volunteers.     

Metaproteomics reveals the structural and functional diversity of Dermatocarpon miniatum (L.) W. Mann. Microbiota

Metaproteomics is a strategy to understand the taxonomy, functionality and metabolic pathways of the microbial communities. The relationship among the symbiotic microbiota in the entire lichen thallus, Dermatocarpon miniatum, was evaluated using the metaproteomic approach. Proteomic profiling using one-dimensional SDS-PAGE followed by LC-MS/MS analysis resulted in a total of 138 identified proteins via Mascot search against UniRef100 and Swiss-Prot databases. In addition to the fungal and algal partners, D. miniatum proteome encompasses proteins from prokaryotes, which is a multifarious community mainly dominated by cyanobacteria and proteobacteria. While proteins assigned to fungus were the most abundant (55 %), followed by protists (16 %), bacterial (13 %), plant (11 %), and viral (1 %) origin, whereas 4 % remained undefined. Various proteins were assigned to the different lichen symbionts by using Gene Ontology (GO) terms, e.g. fungal proteins involved in the oxidation-reduction process, protein folding and glycolytic process, while protists and bacterial proteins were involved in photosynthetic electron transport in photosystem II (PS II), ATP synthesis coupled proton transport, and carbon fixation. The presence of bacterial communities extended the traditional concept of fungal-algal lichen symbiotic interaction.     

2种检测灯盏花素血药浓度方法的比较

目的：建立测定Beagle犬血浆中灯盏花素浓度的反相高效液相色谱法和液相-质谱联用法,并将其进行多参数的两两比较。方法：采用液-液萃取法处理血清,反相高效液相色谱法测定,流动相为甲醇-水（pH3．0）=42：58,EclipseXDB-C18为固定相;将同样的样品用液相-质谱法开展平行检测;将所测得的数据做两两对比,采用SPSS统计软件进行分析。结果：2种方法测定的数据具有良好的相关性（r=0．982,P〉0．05）;最低检测限前者为0．05μg／mL,后者为0．01μg／mL,反相高效液相色谱法的最低检测限和灵敏度不及液相-质谱联用法。结论：反相高效液相色谱法可用于灯盏花素毒代动力学研究,与液相-质谱联用法检测结果无显著差异,且费用较低,不失为-种低成本且行之有效的检测方法。     

An LC-MS/MS method for determination of forsythiaside in rat plasma and application to a pharmacokinetic study

A highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of forsythiaside in rat plasma using epicatechin as internal standard. The analytes were extracted by solid-phase extraction and chromatographied on a C₁₈ column eluted with a gradient mobile phase of acetonitrile and water both containing 0.2% formic acid. The detection was performed by negative ion electrospray ionization in multiple reaction monitoring mode, monitoring the transitions m/z 623 → 161 and m/z 289 → 109 for forsythiaside and epicatechin, respectively. The assay was linear over the concentration ranges of 2.0–50.0 and 50.0–5000.0 ng/mL with limits of detection and quantification of 0.2 and 1.0 ng/mL, respectively. The precision was <10.8% and the accuracy was >91.9%, and extraction recovery ranged from 81.3% to 85.0%. This method was successfully applied to a pharmacokinetic study of forsythiaside in rats after intravenous (20 mg/kg) and oral (100 mg/kg) administration, and the result showed that the compound was poorly absorbed with an absolute bioavailability being approximately 0.5%.     

GC/MS-SCAN to follow the fate of crude oil components in bioreactors set to remediate contaminated soil

In this paper GC/MS-SCAN was used to identify the crude oil components that persist after bioremediation treatment of contaminated soil and the metabolites generated during this process. The soil was treated in bioreactors inoculated with an adapted bacterial population. In the first of two sets of conditions used, the water phase of the reactor was circulated continuously at a flow rate of 7 l day⁻¹, and in the other case, it was circulated for a short period once a day to give the equivalent of 0.5 l day⁻¹. Data showed that acyclic, n- and substituted alkanes C₁₂ were still present after one year of remediation, while the majority of substituted derivatives of polycyclic and aromatic hydrocarbons could not be detected by GC/MS-SCAN analysis. The number of components identified was about one-half of that initially observed. After treatment the same number of components was detected at the top and bottom of the reactor in which the water phase was circulated continuously, whereas a smaller number of metabolites were observed at the top rather than at the bottom of the reactor with discontinuous circulation. The analysis has pointed to the importance of n-alkanes, their substituted derivatives and polycyclic aromatic hydrocarbons as the most significant pollutants.     

LC-MS/MS 检测癫痫患者神经递质类氨基酸

目的:建立液相色谱串联质谱同位素内标法检测神经递质类氨基酸并用于癫痫患者临床评价.方法:选用AAA-C18柱色谱柱,以乙腈水(含有0.01%七氟丁酸、0.1%甲酸)为流动相,采用梯度洗脱进行分离,血浆样品用iTRAQ-115衍生化试剂处理后,加入iTRAQ-114衍生化的氨基酸内标并进样,选用3200QTRAP型质谱仪的多重反应监测(MRM)扫描方式进行检测.疾病组与健康组的统计采用t检验和主成份分析.结果:疾病组和健康组氨基酸测定结果显示:Trp、GABA两组间没有显著性差异(P＞0.05),Arg、Glv、Ser、Tau、Asp、Glu、EtN、两组间有显著性差异(P＜0.05),通过PCA分析显示,疾病组与健康组之间差异明显,Asp、Glu、Ser等是引起差异的主要氨基酸.结论:试验方法灵敏、专属性强,并初步的用于癫痫患者体内氨基酸评价.