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American Journal of Analytical Chemistry 2011年第2期2卷 217-222页

作者： Hanwen Sun Lixin Li 不详

Lead and cadmium in herbal medicines are highly toxic to living organisms even in low concentrations. An effective method is developed for analysis of trace lead and cadmium in Chinese herbal medicines and their decoctions by graphite furnace atomic absorption spectrometry (GFAAS). The effects of analytical conditions on absorbance were investigated and optimized. A water-dissolving capability for Pb and Cd was investigated, and the contents of different species in five Chinese herbal medicines and their decoctions were analyzed. The content ratios (kow) of n-octanol-soluble Pb or Cd to water-soluble Pb or Cd were evaluated, and the distribution of Pb and Cd in water decoction at stomach and intestine acidities was developed, in the first time. The contents of water-soluble Pb and Cd, n-octanol-soluble Pb and Cd, and their content ratios were related with the kind of medicine and the acidity of the decoction. The proposed method has the advantages of simple operation, high sensitivity and high speed, with 3 σ detection limits of 4.2 pg for Pb and 0.1 pg for Cd.

关键词： Distribution Lead Cadmium Herbal Medicines Decoctions Graphite Furnace Atomic Absorption spectrometry

Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence spectrometry

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American Journal of Analytical Chemistry 2014年第12期5卷 766-774页

作者： Sung-Mo Jung Graduate Institute of Ferrous Technology Pohang University of Science and Technology Pohang Korea

A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.

关键词： FeMo Alloys X-Ray Fluorescence spectrometry Borate Fusion Pre-Oxidation Calibration Standard Quantification

Characterization of Tars from the Thermal Processing of Baganuur and Tavan Tolgoi Coals from Mongolia, Using SEC, UV-F, IR and Mass spectrometry

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Advances in Chemical Engineering and Science 2013年第2期3卷 130-144页

作者： Barnasan Purevsuren Yadamsuren Davaajav Sanjaa Batbilig Jargalsaikhan Namkhainorov Fatma Karaca Trevor J. Morgan Patricia Alvarez Rodriguez Feng H. Tay Sergei Kazarian Alan A. Herod Rafael Kandiyoti Institute of Chemistry and Chemical Technology Mongolian Academy of Sciences Ulaanbaatar Mongolia

Tars from two Mongolian coals (Tavan Tolgoi and Baganuur) produced by simple distillation have been characterized using size exclusion chromatography (SEC) with elution in both 1-methyl-2-pyrrolidinone (NMP) and a mixed solvent (NMP and chloroform), UV-fluorescence in chloroform and NMP, gas chromatography (GC), mass spectrometry (GC-MS, probe-MS and LD-MS with thin layer chromatography) and infra-red spectroscopy. The SEC chromatograms using NMP and the solvent mixture NMP: chloroform indicates that similar conclusions can be drawn from using either eluent. The synchronous UV-fluorescence spectra were shifted to longer wavelengths in chloroform solution than in NMP and chloroform may be the better solvent for these tars prepared without extensive secondary thermal treatment. Infra-red spectra indicated differences between the two coal tars that reflected their different ranks, with more oxygenate groups in the lower rank Baganuur coal. Mass spectrometry (GC-MS and probe-MS) of both coal tars confirmed the presence of aliphatic components as well as aromatics and the relatively extensive alkylation of aromatics. Molecular mass ranges indicated for Baganuur tar by SEC compared well with the mass range by LD-MS although the LD-MS extended to higher mass values. The high mass fractions of the tars were revealed by fractionation by thin layer chromatography with the relevant sections of the developed plates inserted directly into the mass spectrometer;laser desorption was directly from the surface of the plate. LD-MS of the unfractionated samples failed to detect the high mass components because of mass discrimination effects. The high mass components were carried over in the distillation by mass transfer of vapours into the condenser.

关键词： Mongolian Coals Tar Preparation Characterization Laser Desorption Mass spectrometry Thin Layer Chromatography

Measuring Conditions for the Determination of Lead in Iron-Matrix Samples Using Graphite Atomizers with/without a Platform in Graphite Furnace Atomic Absorption spectrometry

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American Journal of Analytical Chemistry 2011年第6期2卷 710-717页

作者： Syun Morimoto Tetsuya Ashino Kazuaki Wagatsuma 不详

In graphite furnace atomic absorption spectrometry (GF-AAS), the atomization process of lead occurring in graphite atomizers with/without a platform plate was investigated when palladium was added to an iron-matrix sample solution containing trace amounts of lead. Absorption profiles of a lead line were meas- ured at various compositions of iron and palladium. Variations in the gas temperature were also estimated with the progress of atomization, by using a two-line method under the assumption of a Boltzmann distribu- tion. Each addition of iron and palladium increased the lead absorbance in both the atomizers, indicating that iron or palladium became an effective matrix modifier for the determination of lead. Especially, palladium played a significant role for controlling chemical species of lead at the charring stage in the platform-type atomizer, to change several chemical species to a single species and eventually to yield a dominant peak of the lead absorbance at the atomizing stage. Furthermore, the addition of palladium delayed the peak after the gas atmosphere in the atomizer was heated to a higher temperature. These phenomena would be because the temperature of the platform at the charring stage was elevated more slowly compared to that of the furnace wall, and also because a thermally-stable compound, such as a palladium-lead solid solution, was produced by their metallurgical reaction during heating of the charring stage. A platform-type atomizer with palladium as the matrix modifier is recommended for the determination of lead in GF-AAS. The optimum condition for this was obtained in a coexistence of 1.0 × 10–2 g/dm3 palladium, when the charring at 973 K and then the atomizing at 3073 K were conducted.

关键词： Graphite Furnace Atomic Absorption spectrometry Platform Atomizer Gas Temperature Matrix Modifier Lead Iron Palladium

Gel Permeation Chromatography Purification and Gas Chromatography-Mass spectrometry Detection of Multi-Pesticide Residues in Traditional Chinese Medicine

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American Journal of Analytical Chemistry 2012年第1期3卷 24-32页

作者： Wan-E Zhuang Zhen-Bin Gong 不详

The measurement of 23 organochlorine, organophosphorus, and pyrethroid pesticides in typical traditional Chinese medicine (TCM), flos lonicerae, was made using gel permeation chromatography (GPC) purification and gas chroma- tography-mass spectrometry (GC-MS) detection. The pesticides were extracted with ultrasonic device and 5.0 mL mixture of ethyl acetate and cyclohexane (1:1, v/v). Coextractants from sample matrices which may have interfere to the qualitative and quantitative analysis, such as pigments, were removed using GPC purification. Simultaneous full scan and selective ion monitor (scan/SIM) mode for GC-MS was used for qualitative and quantitative analysis, which pro- vided retention time and characteristic fragments ratio for each pesticide so as to positively identify each analyte. Rela- tive standard deviations (RSDs) were within 7.7% (5.0 - 22.5 μg/kg, n = 3). The recoveries of pesticide standards at the spiked concentration of 5.0 - 22.5 μg/kg were between 87.1% and 110.9%. Limits of detection (LODs) for the analytes were 0.16 - 3.2 μg/kg, which could meet the demand of routine analysis and TCM quality control.

关键词： Traditional Chinese Medicine Multi-Pesticide Residue Flos Lonicerae Gel Permeation Chromatography Gas Chromatography-Mass spectrometry

<i>In Situ</i>Analysis of Copper Alloys by Femtosecond Laser Ablation Inductively Coupled Plasma Mass spectrometry: Constrains on Matrix Effects

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American Journal of Analytical Chemistry 2018年第3期9卷 150-161页

作者： Germán Velásquez Anastassia Y. Borisova Sandrine Baron Luc Robbiola Advanced Mining Technology Center (AMTC) FCFM Universidad de Chile Santiago Chile Universidad Central de Venezuela Instituto de Ciencias de la Tierra Caracas Venezuela Géosciences Environnement Toulouse Université de Toulouse UPS OMP-CNRS Toulouse France Geological Department Lomonosov Moscow State University Moscow Russia Université de Toulouse CNRS Laboratoire TRACES (UMR 5608) Toulouse France

Direct analysis of copper-base alloys using laser ablation techniques is an increasingly common procedure in cultural heritage studies. However, main discussions remain focused on the possibility of using non-matrix matched external reference materials. To evaluate the occurrence of matrix effects during in situ microanalysis of copper-base materials, using near infrared femtosecond laser ablation techniques (NIR fs-LA-ICP-MS), two bronzes, i.e., (Sn-Zn)-ternary and (Sn)-binary copper-matrix reference materials, as well as a reference synthetic glass (NIST-SRM-610) have been analyzed. The results have been compared to data obtained on a sulfide-matrix reference material. Similar values in relative sensitivity averages of 63Cu, 118Sn and 66Zn, as well as in 118Sn/63Cu and 66Zn/63Cu ratios were obtained, for all analyzed matrix types, i.e., copper-base-, silicate-, and sulfide-reference materials. Consequently, it is possible to determinate major and minor element concentrations in copper alloys, i.e., Cu, Sn and Zn, using silicate and sulfide reference materials as external calibrators, without any matrix effect and over a wide range of concentrations (from wt.% to ppm). Equally, Cu, Sn and Zn concentrations can be precisely determined in sulfides using homogeneous alloys (reference) materials as an external calibrator. Thus, it is possible to determine Cu, Sn and Zn in copper-base materials and their ore minerals, mostly sulfides, in a single analytical session, without requiring specific external calibrators for each matrix type. In contrast, immiscible elements in copper matrix, such as Pb and Fe show notable differences in their relative sensitivity values and ratios for different matrix-materials analyzed, implying that matrix-matched external calibrations remain to be applied for their trace quantification.

关键词： Copper Alloys Reference Material Matrix Effect In-Situ Metal Determinations Near-Infrared Femtosecond Laser Ablation-Inductively Coupled Plasma-Mass spectrometry (NIR fs-LA-ICP-MS)

Reduction of Internal Standard Signals in Quantitative MALDI-TOF Mass spectrometry

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Journal of Analytical Sciences, Methods and Instrumentation 2012年第3期2卷 120-125页

作者： Walter B. Wilson Dickson M. Wambua Norman H. L. Chiu Department of Chemistry and Biochemistry University of North Carolina at Greensboro Greensboro USA Department of Chemistry and Biochemistry University of North Carolina at Greensboro Greensboro USA 2Department of Nanoscience Joint School of Nanoscience and Nanoengineering Greensboro USA. Department of Nanoscience Joint School of Nanoscience and Nanoengineering Greensboro USA.

The advantages of combining qualitative and quantitative analysis on a single analytical technique have further extended the applications of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to the quantitation of various biomolecules. To achieve absolute quantitation, it is necessary to perform a calibration with standard dilutions. For the purpose of measuring DNA samples, a pure DNA oligonucleotide at different concentrations was chosen as a standard to perform the calibration of MALDI-TOF MS. In order to overcome the variation of signal intensity from repeated measurements of each DNA standard dilution, fixed amount of an internal standard was added into each DNA standard dilution. Instead of maintaining at a constant level, the signals of fixed amount of internal standard were decreased 73% from its initial level while the signals of DNA standard continued to increase within a linear dynamic range for quantitation from 0.20 μM to 12.5 μM of DNA. Attempts to identify the cause of signal reduction were systematically carried out. This is the first report on the extent of signal reduction in quantitative MALDI-TOF MS. These results represent a limitation on using MALDI-TOF MS to monitor the changes in concentration of two different compounds within a chemical or biological system.

关键词： MALDI Mass spectrometry Quantitation

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

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Science China(Life Sciences) 2000年第6期43卷 561-568页

作者：车发云邵晓霞夏其昌 Shanghai Institute of Biochemistry Chinese Academy of Sciences Shanghai 200031 China

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.

关键词： high performance liquid chromatography-ion trap mass spectrometry phosphorylation site identification.

Determination of 24 Allergens in Perfume with High Performance Liquid Chromatography Tandem Mass spectrometry

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China Detergent & Cosmetics 2019年第1期4卷 40-46页

作者： Wang Yujian Liang Zhengang Fu Lingmei Dong Cunzhu Technology Center of Hainan Entry-Exit Inspection and Quarantine Bureau China China College of Environment and Plant Protection Hainan UniversityChina

A method of 24 allergens determination in cosmetics were established with high performance liquid chromatography tandem mass spectrometry. The targeted compounds were extracted with acetonitrile and determined with LC-MS/MS (MRM mode) with external method. The linearity between concentrations and peak area ratio was obtained from 1.0~5.0 mg/L. The limits of detection were 1.0 mg/L for the instrument and 5.0 mg/kg for the method respectively. The LOQ was 15.0 mg/L. The average recoveries of 24 allergens were between 85.9% and 110.0% at spiked levels of 5, 10 and 20 mg/kg with relative standard derivation (RSDs) of 5.5%~12.0%(n=10). The method could be used as a reliable means for simultaneous quantitative determination of allergens in cosmetics.

关键词： perfume allergens flavor high performance liquid chromatography tandem mass spectrometry

Importance of quality control in lipidomics profiling based on mass spectrometry

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Oil Crop Science 2017年第4期2卷 217-224页

作者： Ya Xie Huifang Ma Fang Wei Xin Lyu Zongyuan Wu Bangfu Wu Shuling Xu Xuyan Dong Hong Chen Fenghong Huang Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences Key Laboratory of Oilseeds Processing of Ministry of Agriculture Key Laboratory of Biology and Genetic Improvement of Oil Crops of Ministry of Agriculture P. R.China Hubei Key Laboratory of Lipid Chemistry and Nutrit

As a current analytical instrument for lipidomics profiling with high sensitivity, selectivity, and throughput, mass spectrometry (MS) has been widely used in the field of clinical medicine, nutrition, bromatology, botany and etc. During the routine use of shotgun- MS and high performance liquid chromatography-MS (HPLC-MS) in lipid analysis, an important problem to be solved is the defective repeatability and stability resulting from signal attenuation or drifts in LC-peak shape and retention time of MS platform. To remove or minimize the influence, extensively accepted and applied QC (quality control) samples must be performed. In this review, we emphasize the importance of the application of QC samples, which could 1) provide the ability to equilibrate the analytical platform at the beginning; 2) act as a quality assurance (QA) procedure during the analytical process; 3) perform signal correction in the data handling with the purpose of reducing analytical variation and improving the precision of quantitative analysis; 4) the data between different laboratories can be compared through the incorporation of particular QC samples-Standard Reference Material (SRM) 1950. In addition, we display 4 types and requirements of QC samples during quality control in lipidomics profiling. Lipidomics profiling based on MS strongly requires commonly accepted guidelines for quality control to perform routine, large-scale researches, so as to integrate data from different scientists for more information.

关键词： quality control lipidomics mass spectrometry correction standardization