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Determination of lead in botanicals/Chinese prepared medicines by using microwave digestion with flow injection-inductively coupled plasma-mass spectrometry

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JOURNAL OF AOAC INTERNATIONAL 2000年第2期83卷 382-389页

作者： Ong, ES Yong, YL Woo, SO Dept Sci Serv Inst Sci & Forens Med Singapore 169078 Singapore

A simple, sensitive, and rapid method was developed for the determination of lead in botanicals and Chinese prepared medicines (CPM) by using closed-vessel microwave digestion with flow injection-inductively coupled plasma-mass spectrometry. The limits of detection and quantitation for the method, based on 0.5 g digested sample, were calculated to be 0.10 and 0.61 mg/kg, respectively. A simple approach was proposed for calibration by multiple linear regression (MLR) with Pb-207, Pb-206, and Pb-204 for the determination of lead in botanical and CPM samples. The results from calibration by MLR were compared with those obtained by conventional modes using Pb-207 and the sum of Pb-207 and Pb-206. Th, results obtained by the different modes of calibration were in good agreement for botanical and CPM samples. The method was found to have good accuracy for the analysis of botanical reference materials. Method precision based on analyses of different types of CPM samples by different analysts on different days for different levels of lead was between 3.0 and 8.0 % (relative standard deviation, n = 6). The effect of possible matrix interference caused by nitric acid and the extent of digestion was investigated with the method of standard additions. Significant matrix interference was not observed for the CPM samples analyzed. MLR was used to examine the effect of variation in isotopic abundance, which was found to present no significant problem in the determination of lead in the botanical and CPM samples.

关键词：校准中草药/分析同位素铅/分析线性模型质谱分析法/方法微波硝酸植物药用/化学敏感性与特异性

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Stable isotope incorporation triples the upper mass limit for determination of elemental composition by accurate mass measurement

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JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2000年第10期11卷 835-840页

作者： Rodgers, RP Blumer, EN Hendrickson, CL Marshall, AG Florida State Univ Natl High Magnet Field Lab Ctr Interdisciplinary Magnet Resonance Tallahassee FL 32310 USA

By comparing electrospray ionization Fourier-transform ion cyclotron resonance (FT-ICR) mass spectra and collision-induced dissociation (CID) FT-ICR mass spectra of a phospholipid (851 Da) extracted from natural abundance and 99% C-13 bacterial growth media, we are able to reduce its number of possible elemental compositions (based on +/-10 ppm externally calibrated mass accuracy and biologically relevant compositional constraints) from 394 to 1. The basic idea is simply that the mass of a molecule containing N carbon atoms increases by N Da when C-12 is replaced by C-13. Once the number of carbons is known, the number of possible combinations of other atoms in the molecule is greatly reduced. We demonstrate the method for a stored-waveform inverse Fourier transform-isolated phospholipid from an extract of membrane lipids from Rhodococcus rhodochrous hydrocarbon-degrading bacteria grown on either natural abundance or 99% C-13-enriched mixtures of n-hexadecane and n-octadecane. We project that this method raises the upper mass limit for unique determination of elemental composition from accurate mass measurement by a factor of at least 3, thereby extending "chemical formula" determination to identification and sequencing of larger synthetic and bio-polymers: phospholipids, oligopeptides of more than three to four amino acids, DNA or RNA of more than two nucleotides, oligosaccharides of more than three sugars, etc. The method can also be extended to determination of the number of other atoms for which heavy isotopes are available (e.g., N-15, S-34, O-18, etc.). (J Am Soc Mass Spectrom 2000, 11, 835-840) (C) 2000 American Society for Mass Spectrometry.

关键词：碳同位素培养基/分析傅里叶分析质谱分析法/方法氮同位素磷脂类/化学红球菌属/化学

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A microdevice with integrated liquid junction for facile peptide and protein analysis by capillary electrophoresis/electrospray mass spectrometry

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ANALYTICAL CHEMISTRY 2000年第5期72卷 1015-1022页

作者： Zhang, BL Foret, F Karger, BL Northeastern Univ Barnett Inst Boston MA 02115 USA Northeastern Univ Dept Chem Boston MA 02115 USA

A novel microfabricated device was implemented for facile coupling of capillary electrophoresis with mass spectrometry (CE/MS), The device was constructed from glass wafers using standard photolithographic/wet chemical etching methods. The design integrated (a) sample inlet ports, (b) the separation channel, (c) a liquid junction, and (d) a guiding channel for the insertion of the electrospray capillary, which was enclosed in a miniaturized subatmospheric electrospray chamber of an ion trap MS. The replaceable electrospray capillary was precisely aligned with the exit of the separation channel by a microfabricated guiding channel. No glue was necessary to seal the electrospray capillary. This design allowed simple and fast replacement of either the microdevice or the electrospray capillary. The performance of the device was tested for CE/MS of peptides, proteins, and protein tryptic digests. On-line tandem mass spectrometry was used for the structure identification of the protein digest products. High-efficiency/high-resolution separations could be obtained on a longer channel (11 cm on-chip) microdevice, and fast separations (under 50 s) were achieved with a short (4.5 cm on-chip) separation channel. In the experiments, both electrokinetic and pressure injections were used. The separation efficiency was comparable to that obtained from conventional capillary electrophoresis.

关键词：电泳毛细管/方法质谱分析法/方法肽类/分析蛋白质类/分析动物人类

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Applications of hyphenated LC-MS techniques in pharmaceutical analysis

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BIOMEDICAL CHROMATOGRAPHY 2000年第6期14卷 373-383页

作者： Ermer, J Vogel, M Aventis Pharma Deutsch GmbH Global Pharmaceut Dev Analyt Sci D-65926 Frankfurt Germany

In pharmaceutical analysis, ie the analytical development and quality control of drug substances and dosage forms, mass spectrometry (MS) combined with chromatographic separation is perhaps the most powerful technique for the monitoring, characterization and identification of impurities. The addition of further dimensions to chromatographic separations by hyphenated techniques offers unique possibilities of efficiently supporting pharmaceutical development and ensuring the quality and safety of pharmaceuticals. However, the ionization process in MS involves some characteristics which have to be recognized and taken into account for an appropriate application as well as the evaluation of the results. Chromatographic method development and validation can be supported very effectively by MS detection, eg in the investigation of coelution and peak purity. Chiral amino acid analysis is largely facilitated by the mass-specific detection of the derivatized amino acid enantiomers, which ignores all other interfering substance peaks. Examples are presented for the use of LC-MS-MS fragmentation and high-resolution MS in the structural elucidation of degradation products and impurities. LC-MS is systematically applied to monitor impurity profiles during pharmaceutical development and scaling up and supports the safety evaluation of batches used in clinical studies. Copyright (C) 2000 John Wiley & Sons, Ltd.

关键词：氨基酸类/分析化学药物色谱法液相/方法药物污染质谱分析法/方法药用制剂/分析

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Optimization of the isotope-coded affinity tag-labeling procedure for quantitative proteome analysis

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ANALYTICAL BIOCHEMISTRY 2001年第1期297卷 25-31页

作者： Smolka, MB Zhou, HL Purkayastha, S Aebersold, R Inst Syst Biol Seattle WA 98105 USA Univ Estadual Campinas Inst Biol Dept Bioquim Campinas SP Brazil Appl Biosyst Inc Framingham MA 01701 USA

The combination of isotope coded affinity tag (ICAT) reagents and tandem mass spectrometry constitutes a new method for quantitative proteomics. It involves the site-specific, covalent labeling of proteins with isotopically normal or heavy ICAT reagents, proteolysis of the combined, labeled protein mixture, followed by the isolation and mass spectrometric analysis of the labeled peptides. The method critically depends on labeling protocols that are specific, quantitative, general, robust, and reproducible. Here we describe the systematic evaluation of important parameters of the labeling protocol and describe optimized labeling conditions. The tested factors include the ICAT reagent concentration, the influence of the protein, SDS, and urea concentrations on the labeling reaction, and the reaction time. We demonstrate that using the optimized conditions specific and quantitative labeling was achieved on standard proteins as well as in complex protein mixtures such as a yeast cell lysate. (C) 2001 Academic Press.

关键词：亲和力标记物/分析亲和力标记物/化学合成亲和力标记物/代谢半胱氨酸/分析电泳凝胶双向电泳聚丙烯酰氨凝胶同位素标记/方法乳清蛋白/化学乳清蛋白/代谢质谱分析法/方法分子量肽碎片/化学肽碎片/代谢蛋白质组/分析蛋白质组/化学蛋白质组/代谢酵母菌酿酒/化学酿酒酵母蛋白质类/化学十二烷硫酸钠/代谢时间因素胰蛋白酶/代谢尿素/代谢

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On-line sample clean-up and chromatography coupled with electrospray ionization mass spectrometry to characterize the primary sequence and disulfide bond content of recombinant calcium binding proteins

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BIOMEDICAL CHROMATOGRAPHY 1999年第1期13卷 37-45页

作者： Johnson, KL Veenstra, TD Londowski, JW Tomlinson, AJ Kumar, R Naylor, S Mayo Clin & Mayo Fdn Biomed Mass Spectrometry Facil Rochester MN 55905 USA Mayo Clin & Mayo Fdn Nephrol Res Unit Rochester MN 55905 USA Mayo Clin & Mayo Fdn Dept Med Rochester MN 55905 USA Mayo Clin & Mayo Fdn Dept Biochem & Mol Biol Rochester MN 55905 USA Mayo Clin & Mayo Fdn Dept Pharmacol Rochester MN 55905 USA Mayo Clin & Mayo Fdn Clin Pharmacol Unit Rochester MN 55905 USA

We have used on-line sample clean-up, concentration, and chromatography with electrospray ionization mass spectrometry (ESI-MS), to characterize and determine the presence of disulfide bonds in recombinant full-length rat brain calbindin D-28K and two deletion mutants of the protein, one lacking EF-hand 2 (calbindin Delta 2) and the other lacking EF-hands 2 and 6 (calbindin Delta 2,6). The molecular weights of the expressed proteins dissolved in biological buffers were determined with high accuracy using a low-flow, pressurized chamber infusion system, that allows on-line protein clean-up by removing buffers/salts incompatible with ESI-MS. The molecular weight determinations showed that the amino-terminal methionine residues had been cleaved during the expression and isolation of the recombinant proteins. Approximately 85-90% of the protein sequences were confirmed by on-line HPLC-ESI-MS analysis of peptides generated by a lysyl endoproteinase C digestion. Comparisons of ESI-MS spectra of native and reduced calbindin D-28K and Delta 2 show that the full length- and Delta 2 mutant-protein contain one disulfide bond. Molecular mass determinations of calbindin Delta 2,6 showed that this protein contains a highly active cysteine residue that covalently binds a mercaptoethanol group, or forms a homodimer via a disulfide bond. The results show surprising differences amongst the deletion mutants of calbindin D28K With respect to the formation of disulfide bonds. These differences are not readily detected by other techniques and show that ESI-MS is a powerful, rapid method by which to detect disulfide linkages for intact proteins. Copyright (C) 1999 John Wiley & Sons, Ltd.

关键词：氨基酸序列色谱法高压液相/方法二硫化物类/分析质谱分析法/方法分子序列数据分子量重组蛋白质类/化学动物大鼠

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Narrow-band collisional activation technique for ion trap mass spectrometers

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ANALYTICAL CHEMISTRY 1999年第14期71卷 2945-2950页

作者： Baker, AG Alexander, A Novotny, MV Indiana Univ Dept Chem Bloomington IN 47405 USA

Narrow-bandwidth signals were applied to the end caps of an ion trap mass spectrometer to excite ions during collisional activation. Excitation waveforms were created from a single-frequency component and a random noise component using a multiplier circuit. Tandem and higher order mass spectrometry experiments (MS3) can be performed without optimization of the supplemental frequency applied to the end cap electrodes. The usefulness of this method of ion excitation is demonstrated using singly and multiply protonated peptide ions as well as sodium-cationized carbohydrates.

关键词：氨基酸序列血管紧张素Ⅱ/化学碳水化合物序列质谱分析法/方法分子序列数据寡糖类/化学

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Binding of nucleotides to guanylate kinase, p21^ras, and nucleoside-diphosphate kinase studied by nano-electrospray mass spectrometry

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JOURNAL OF BIOLOGICAL CHEMISTRY 1999年第50期274卷 35337-35342页

作者： Prinz, H Lavie, A Scheidig, AJ Spangenberg, O Konrad, M Max Planck Inst Mol Physiol D-44227 Dortmund Germany Max Planck Inst Biophys Chem D-37070 Gottingen Germany

The binding of nucleotides to three different nucleotide-binding proteins and to a control protein was studied by means of nano-electrospray mass spectrometry applied to aqueous nondenaturing solutions. The method leads to unambiguous identification of enzyme complexes with substrates and products but does not allow the determination of dissociation constants or even stoichiometries relevant to the binding in solution. For guanylate kinase (EC 2.7.4.8), the transfer of HPO3 between nucleotides was observed whenever a ternary complex with adenylate or guanylate nucleotides was formed. Guanosine 5'-tetraphosphate was generated after prolonged incubation with GDP or GTP, Mg2+ binding was considerably enhanced in functional high affinity complexes, such as observed between guanylate kinase and its bisubstrate inhibitor P-1-(5'-guanosyl)-P-5-(5'-adenosyl) pentaphosphate or with the tight nucleotide-binding protein p21(ras) and GDP. Nucleoside-diphosphate kinase (EC 2.7.4.6) itself was phosphorylated in accordance to its known ping-pong mechanism. All nucleotide-binding proteins were shown to bind sulfate (SO42-) with presumably high affinity and slow exchange rate. The binding of phosphate (PO43-) could be inferred indirectly from competition with SO42-.

关键词：结合部位鸟嘌呤核苷酸类/代谢鸟苷二磷酸/化学鸟苷二磷酸/代谢鸟苷四磷酸/代谢鸟苷三磷酸/化学鸟苷三磷酸/代谢动力学质谱分析法/方法核苷二磷酸激酶/化学核苷二磷酸激酶/代谢核苷一磷酸激酶/化学核苷一磷酸激酶/代谢磷酸盐类/代谢原癌基因蛋白质p21(ras)/化学原癌基因蛋白质p21(ras)/代谢重组蛋白质类/化学重组蛋白质类/代谢酿酒酵母菌/酶学硫酸盐类/代谢人类

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Detection of the dipicolinic acid biomarker in Bacillus spores using Curie-point pyrolysis mass spectrometry and fourier transform infrared spectroscopy

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ANALYTICAL CHEMISTRY 2000年第1期72卷 119-127页

作者： Goodacre, R Shann, B Gilbert, RJ Timmins, ÉM McGovern, AC Alsberg, BK Kell, DB Logan, NA Univ Wales Inst Biol Sci Aberystwyth SY23 3DD Ceredigion Wales Univ Wales Dept Comp Sci Aberystwyth SY23 3DB Ceredigion Wales Glasgow Caledonian Univ Sch Biol & Biomed Sci Glasgow G4 0BA Lanark Scotland

Thirty-six strains of aerobic endospore-forming bacteria confirmed by polyphasic taxonomic methods to belong to Bacillus amyloliquefaciens, Bacillus cereus, Bacillus licheniformis, Bacillus megaterium, Bacillus subtilis (including Bacillus niger and Bacillus globigii), Bacillus sphaericus,and Brevi laterosporus were grown axenically on nutrient agar, and vegetative and sporulated biomasses were analyzed by Curie-point pyrolysis mass spectrometry (PyMS) and diffuse reflectance-absorbance Fourier-transform infrared spectroscopy (FT-IK), Chemometric methods based on rule induction and genetic programming were used to determine the physiological state (vegetative cells or spores) correctly, and these methods produced mathematical rules which could be simply interpreted in biochemical terms. For PyMS it was found that m/z 105 was characteristic and is a pyridine ketoniun ion (C6H3ON+) obtained from the pyrolysis of dipicolinic acid (pyridine-2,6-dicarboxylic acid;DPA), a substance found in spores but not in vegetative cells;this was confirmed using pyrolysis-gas chromatography/mass spectrometry, In addition, a pyridine ring vibration at 1447-1439 cm(-1) from DPA was found to be highly characteristic of spores in FT-IR analysis. Thus, although the original data sets recorded hundreds of spectral variables from whole cells simultaneously, a simple biomarker can be used for the rapid and unequivocal detection of spores of these organisms.

关键词：芽孢杆菌属/化学芽孢杆菌属/分类芽孢杆菌属/遗传学热温度质谱分析法/方法吡啶羧酸类/分析谱学傅里叶变换红外孢子细菌/化学孢子细菌/分类孢子细菌/遗传学

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Analysis of in vivo-derived amyloid-β polypeptides by on-line two-dimensional chromatography-mass spectrometry

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ANALYTICAL BIOCHEMISTRY 2001年第1期298卷 32-39页

作者： Clarke, NJ Crow, FW Younkin, S Naylor, S Mayo Clin & Mayo Fdn Dept Chem & Mol Biol Biomed Mass Spectrometry & Funct Proteom Facil Rochester MN 55905 USA Mayo Clin & Mayo Fdn Dept Pharmacol Rochester MN 55905 USA Mayo Clin & Mayo Fdn Clin Pharmacol Unit Rochester MN 55905 USA Mayo Clin Dept Pharmacol Jacksonville FL 32224 USA

The presence of senile plaques composed of amyloid-beta (A beta) polypeptides within brain tissue is normally used as a definitive postmortem diagnosis for Alzheimer's Disease (AD). Therefore, these polypeptides have been investigated as potential biomarkers of the disease state. However, at present, there is a lack of a robust assay for the detection of such polypeptides derived from in vivo sources. Such an assay is essential for analysis of biological samples from model AD systems. To overcome this problem we have developed a new single-step assay utilizing two dimensional-chromatography in conjunction with mass spectrometry. The method consists of on-line size-exclusion chromatography (SEC) to provide initial separation of analytes from the sample (based on their molecular weight) coupled with sample preconcentration prior to analysis by microbore high-performance liquid chromatography-mass spectrometry (HPLC-MS). This provides an extremely versatile and powerful assay which can separate specific analytes from cell lysate in a single step without further sample handling. The use of mass spectrometry as the detection system yields much more structural information than can be obtained from traditional ELISA and sandwich ELISA antibody assays. Furthermore, the on-line sample cleanup protocol minimizes sample handling and facilitates assay automation. Utilizing this new assay we have been able to detect A beta 1-40 and A beta 1-42 at cellular concentration levels directly from cell lysates. Moreover, we have detected multiple peptide responses within the same analysis, some of which have been tentatively identified as other ragged C-termini A beta polypeptides derived from A beta 1-42, based on their molecular weight, as well as oxidized A beta polypeptides. (C) 2001 Academic Press.

关键词：淀粉样β蛋白/分析淀粉样β蛋白/化学合成脑/细胞学脑化学细胞培养的/化学细胞培养的/细胞学色谱法凝胶/仪器和设备色谱法高压液相/仪器和设备培养基条件性/化学质谱分析法/仪器和设备质谱分析法/方法联机系统/仪器和设备肽碎片/分析肽碎片/化学合成动物豚鼠

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