@article {doi:10.1002/elps.201900456, title = {Application of multisegment injection on quantification of creatinine and standard addition analysis of urinary 5-hydroxyindoleacetic acid simultaneously with creatinine normalization}, journal = {ELECTROPHORESIS}, volume = {41}, number = {n/a}, year = {2020}, pages = {183-193}, abstract = {

Abstract In this paper, the development of a simple dilute-and-shoot method for quantifying urinary creatinine by CE\–ESI\–MS was described. The creatinine analysis time was about 7\ min/sample by conventional single injection (SI) method and can be significantly reduced to less than 2\ min/sample with multi-segment injection (MSI). In addition, the standard addition analysis of 5-hydroxyindole-3-acetic acid (5-HIAA) and creatinine normalization was performed within one run by the MSI technique, and the total analysis time was 14-min faster compared to the SI method for analyzing the same set of samples. The uses of isotopic and non-isotopic internal standards (ISs) were compared. Creatinine-(methyl-13C) and 5-hydroxyindole-4,6,7-D3-3-acetic-D2 acid (5-HIAA-D5) used as isotopic ISs can provide both accurate and precise results. In contrast, 1,5,5-trimethylhydantoin (1,5,5-TH) used as the non-isotopic IS for creatinine may cause a bias of over 13\% in SI method and even worse when the MSI technique was used. Another compound, 2-methyl-3-indoleacetic acid (2-MIAA), was determined not suitable for MSI analysis of 5-HIAA due to endogenous interferences despite its acceptable performance in conventional methods of analysis.

}, keywords = {capillary electrophoresis, creatinine normalization, MASS SPECTROMETRY, multisegment injection, urinary 5-hydroxyindoleacetic acid}, doi = {10.1002/elps.201900456}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/elps.201900456}, author = {Huang, Zi-Ao and Scotland, Kymora B. and Li, Yueyang and Guo, Jian-Ping and McGeer, Patrick L. and Lange, Dirk and Chen, David D. Y.} } @article {JIANG2020116591, title = {Combining online size exclusion chromatography and electrospray ionization mass spectrometry to characterize plant polysaccharides}, journal = {Carbohydrate Polymers}, volume = {246}, year = {2020}, month = {06/2020}, pages = {116591}, type = {Research}, chapter = {116591}, abstract = {

Characterizing polysaccharides with large molecular weights and isomeric heterogeneity with mass spectrometry (MS) is generally difficult. In this work, we demonstrate how coupling size exclusion chromatography (SEC) and high-resolution MS with source-induced dissociation (SID) can be used for the separation and direct structural evaluation of intact polysaccharides. The analytical method was successfully developed using dextran standards up to 3755\ kDa. This method was used to separate naturally occurring plant polysaccharides based on size, after which numerous polysaccharide fragments were identified from the resulting MS spectra. The results provided strong evidence for structural diversity, complexity, and heterogeneity among polysaccharides. MS showed superior sensitivity and reliability for the polysaccharides in eluted fractions when compared to a refractive index detector. Putative compositions for the fragments were proposed based on exact mass values. The work demonstrated that SEC-SID-MS is a feasible alternative for obtaining valuable structural information from the analysis of intact polysaccharides.

}, keywords = {MASS SPECTROMETRY, Plant polysaccharides, size exclusion chromatography, source-induced dissociation}, issn = {0144-8617}, doi = {https://doi.org/10.1016/j.carbpol.2020.116591}, url = {http://www.sciencedirect.com/science/article/pii/S0144861720307657}, author = {Qing Jiang and Ying Wang and Hongli Li and David D.Y. Chen} } @article {HUANG2020122107, title = {Determination of urinary prostaglandin E2 as a potential biomarker of ureteral stent associated inflammation}, journal = {Journal of Chromatography B}, volume = {1145}, year = {2020}, pages = {122107}, abstract = {Ureteral stents are the most widely used surgical implant in urology. However, they may cause adverse effects to patients, including pain, discomfort, and inflammation. In this work, the inflammatory effect of stent placement and the associated elevation of cyclooxygenase-2 (COX-2) expression were observed. Furthermore, a capillary electrophoresis mass spectrometry (CE-MS) based approach was subsequently developed to quantify urinary prostaglandin E2 (PGE2), a COX-2 metabolite known to contribute to inflammatory renal diseases, to further interrogate the role of this pathway. Urine samples were cleaned and preconcentrated by solid-phase extraction (SPE), and an on-line sample stacking method was used for the enrichment of analytes. The accuracy, precision, and specificity of this method were validated. Standard addition methods were performed to assess the reliability of using deuterated internal standards (IS) in compensating the remaining matrix effect after SPE as well as the detector fluctuation. Through the analysis of 32 pig urine samples, a statistically significant increase of PGE2 was observed in the stented group compared to the unstented (P~=~0.01) and the recovered (P~=~0.004) groups. This work determined that stent placement may contribute to COX-2-dependent inflammation and developed a reliable CE-MS based methodology to quantify PGE2 in stented individuals that may further understand the biology of stent-associated inflammation and inform urologic patient management.}, keywords = {capillary electrophoresis, Cyclooxygenase-2, MASS SPECTROMETRY, Prostaglandin E, Ureteral stent associated inflammation}, issn = {1570-0232}, doi = {https://doi.org/10.1016/j.jchromb.2020.122107}, url = {http://www.sciencedirect.com/science/article/pii/S1570023220302981}, author = {Zi-Ao Huang and Kymora B. Scotland and Yueyang Li and Jiahua Tan and Sonia H.Y. Kung and Ben H. Chew and David D.Y. Chen and Dirk Lange} } @article {YANG202060, title = {A hydrophilic two-dimensional titanium-based metal-organic framework nanosheets for specific enrichment of glycopeptides}, journal = {Analytica Chimica Acta}, volume = {1119}, year = {2020}, pages = {60 - 67}, abstract = {

A hydrophilic two-dimensional titanium-based metal-organic framework (MOF) nanosheets were prepared and applied to improve the glycopeptides enrichment efficiency. Seventeen N-linked glycopeptides from horseradish peroxidase (HRP) tryptic digests were readily identified and the results showed highly improved signal intensities. As the molar ratio of the mixture of tryptic digests of HRP, glycoprotein (HRP), and nonglycoprotein (BSA) reached 1:800:800, good selectivity of the Ti-MOF nanosheets were still clearly observed. As to human serum samples, 41 glycoproteins and 66 glycopeptides corresponding to 68\ N-glycosylation sites were finally detected, which showed the good ability of the nanosheets material to enrich N-linked glycopeptides from complex human serum samples. Moreover, the Ti-MOF nanosheets exhibited unique stability and reusability even after being regenerated and reused for five times. It also performed a high sensitivity (1\ \×\ 10\−10\ M HRP), a good enrichment capacity (250\ mg/g) for glycopeptides enrichment and a high enrichment recovery of 78\%, suggesting a great application prospect for the enrichment of N-linked glycopeptides and the analysis glycoproteomic research.

}, keywords = {Enrichment, Glycopeptides, MASS SPECTROMETRY, Metal-organic frameworks, Nanosheets}, issn = {0003-2670}, doi = {https://doi.org/10.1016/j.aca.2020.04.056}, url = {http://www.sciencedirect.com/science/article/pii/S0003267020304839}, author = {Shi-Shu Yang and Chen Wang and Xizhong Yu and Wenbin Shang and D. D. Y. Chen and Zhi-Yuan Gu} } @article {doi:10.1002/elps.201900195, title = {Analysis of four therapeutic monoclonal antibodies by online capillary isoelectric focusing directly coupled to quadrupole time-of-flight mass spectrometry}, journal = {ELECTROPHORESIS}, volume = {40}, year = {2019}, month = {08/2019}, pages = {2899-2907}, abstract = {

Abstract Capillary isoelectric focusing (cIEF) was online coupled to a Q-TOF MS by a flow-through microvial interface for the analysis of therapeutic mAb. Intact molecular weights obtained from the mass spectrum deconvolution of separated charge variants provided information on the structural heterogeneity of therapeutic mAbs. A sandwich cIEF\–MS configuration composed of anolyte, sample, and catholyte segments sequentially injected into a neutrally coated capillary was used for the charge heterogeneity separation of four mAbs. Acetic acid and ammonium hydroxide were used in places of the non-volatile acids and bases commonly used for IEF but are incompatible with online MS detection. Glycerol was added as the anti-convective reagent. A chemical modifier was mixed with the cIEF effluent in the flow-throw microvial to maintain the ESI stability and to mitigate ion suppression from the co-eluted carrier ampholytes and glycerol. Analysis of mAb samples have shown relative populations of two basic variants originating from C-terminal lysine process and acidic variant of deamidation. The lysine clippings, deamidation, and sialic acid modification in oligosaccharide chains were revealed in infliximab. Two lysine clipping variants and a deamidated variant were observed in adalimumab. The duplicate analyses of a reference mAb demonstrated five charge variants separated by cIEF due to some unidentified modifications, as their mass spectra shared close similarities. The mAb analyses demonstrated the feasibility of the cIEF\–MS method, and they demonstrated how charge and structural variants and minor differences in therapeutic mAbs are observed with this technology. Online cIEF\–MS is an information rich technology with high throughput, demonstrated by the initial data presented here.

}, keywords = {Capillary isoelectric focusing, Charge heterogeneity, MASS SPECTROMETRY, Monoclonal antibodies}, doi = {10.1002/elps.201900195}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/elps.201900195}, author = {Wang, Lingyu and Chen, D.D.Y.} } @article {WANG201894, title = {Optimization of dynamic pH barrage junction focusing for weakly alkaline or zwitterionic analytes in capillary electrophoresis}, journal = {Journal of Chromatography B}, volume = {1095}, year = {2018}, pages = {94 - 102}, abstract = {

Dynamic pH junction focusing prior to electrophoretic separation has been widely used for online pre-concentration of biologically important analytes, which are mostly weakly alkaline/acidic or zwitterionic species such as neurotransmitters, peptides, and proteins. A pH junction is formed when background electrolytes with different pH values are injected sequentially into the separation column of a capillary electrophoresis (CE) system. Unlike the traditional dynamic pH junction configuration with analyte molecules located in a different chemical environment to the separation background electrolyte (BGE), the pH barrage junction has a separate high pH (or low pH) region containing no analyte. Based on Simul 5 Complex simulations and experimental verification with three series of electrolyte combinations, four basic principles for pH barrage junction focusing were identified for its optimization. First, the peak shape after focusing is slightly asymmetric, but this has negligible influence on the analysis result. Second, longer length of the barrage segment is needed for complete focusing with lower concentration of the buffering species. Third, this technique is more advantageous for analytes with relatively high electrophoretic mobility in a capillary without electroosmotic flow. Fourth, provided the analyte region and pH junction buffering species are separated, this quantitative technique is compatible with both optical and mass spectrometric detection.

}, keywords = {capillary electrophoresis, MASS SPECTROMETRY, pH barrage junction, Sample stacking}, issn = {1570-0232}, doi = {https://doi.org/10.1016/j.jchromb.2018.07.023}, url = {http://www.sciencedirect.com/science/article/pii/S1570023218307906}, author = {Lingyu Wang and Wenjun Tong and Chen, David D. Y.} } @article {ELPS:ELPS6157, title = {Improved sensitivity by post-column chemical environment modification of CE-ESI-MS using a flow-through microvial interface}, journal = {ELECTROPHORESIS}, volume = {38}, year = {2017}, month = {06/2017}, pages = {1644{\textendash}1648}, type = {Research}, keywords = {capillary electrophoresis, electrospray ionization, MASS SPECTROMETRY, Peak symmetry, Post-column modification, SENSITIVITY}, issn = {1522-2683}, doi = {10.1002/elps.201600545}, url = {http://dx.doi.org/10.1002/elps.201600545}, author = {Risley, Jessica May and Chen, David Da Yong} } @article {2658, title = {Composition of secondary alcohols, ketones, alkanediols, and ketols in Arabidopsis thaliana cuticular waxes}, journal = {Journal of Experimental Botany}, volume = {60}, number = {6}, year = {2009}, note = {ISI Document Delivery No.: 437ZCTimes Cited: 0Cited Reference Count: 25Wen, Miao Jetter, Reinhard}, month = {Apr}, pages = {1811-1821}, type = {Article}, abstract = {Arabidopsis wax components containing secondary functional groups were examined (i) to test the biosynthetic relationship between secondary alcohols and ketols and (ii) to determine the regiospecificity and substrate preference of the enzyme involved in ketol biosynthesis. The stem wax of Arabidopsis wild type contained homologous series of C-27 to C-31 secondary alcohols (2.4 mu g cm(-2)) and C-28 to C-30 ketones (6.0 mu g cm(-2)) dominated by C-29 homologues. In addition, compound classes containing two secondary functional groups were identified as C-29 diols (similar to 0.05 mu g cm(-2)) and ketols (similar to 0.16 mu g cm(-2)). All four compound classes showed characteristic isomer distributions, with functional groups located between C-14 and C-16. In the mah1 mutant stem wax, diols and ketols could not be detected, while the amounts of secondary alcohols and ketones were drastically reduced. In two MAH1-overexpressing lines, equal amounts of C-29 and C-31 secondary alcohols were detected. Based on the comparison of homologue and isomer compositions between the different genotypes, it can be concluded that biosynthetic pathways lead from alkanes to secondary alcohols, and via ketones or diols to ketols. It seems plausible that MAH1 is the hydroxylase enzyme involved in all these conversions in Arabidopsis thaliana.}, keywords = {BRASSICA-OLERACEA, chain lengths, CHROMATOGRAPHY, cytochrome P450, ECERIFERUM MUTANTS, EPICUTICULAR WAXES, fatty acid derivatives, GAS, HYDROXYLATION, LEAF WAXES, LEAVES, MAH1, MASS SPECTROMETRY, neutral lipids, plant surface composition, RESISTANT, ULTRASTRUCTURE, wax}, isbn = {0022-0957}, url = {://000265524400023}, author = {Wen, M. and Jetter, R.} } @article {2103, title = {Current approaches for global post-translational modification discovery and mass spectrometric analysis}, journal = {Analytica Chimica Acta}, volume = {627}, number = {1}, year = {2008}, note = {ISI Document Delivery No.: 358IYTimes Cited: 13Cited Reference Count: 77Hoffman, Michael D. Sniatynski, Matthew J. Kast, JuergenSp. Iss. SI}, month = {Oct}, pages = {50-61}, type = {Review}, abstract = {More and more attention is being focused on the analysis of post-translational modifications (PTMs) on proteins as researchers are continually learning how essential they are for proper cellular function. As there are hundreds of different types of known PTMs, traditional methods of modification analysis are incapable of comprehensively monitoring for post-translational modifications, a task which is a necessity for truly understanding a cell{\textquoteright}s biology. This review highlights recent developments in novel multiplexed methods of PTM analysis including: fluorescent stain and immuno-based methods, hardware-based mass spectrometric methods and computational-based mass spectrometric methods. Many of these techniques show great promise and will likely be a valuable resource for the biological community. (C) 2008 Elsevier B.V. All rights reserved.}, keywords = {computational, glycosylation, IDENTIFICATION, IONIZATION, marker ion, MASS SPECTROMETRY, MODIFIED PEPTIDES, neutral loss, post-translational modifications, protein array, PROTEIN-PHOSPHORYLATION, PROTEOMIC ANALYSIS, S-NITROSYLATION, SEQUENCES, SIGNALING NETWORKS, SPECTRA}, isbn = {0003-2670}, url = {://000259911600005}, author = {Hoffman, M. D. and Sniatynski, M. J. and Kast, J.} } @article {2180, title = {Twenty years of interface development for capillary electrophoresis-electrospray ionization-mass spectrometry}, journal = {Analytica Chimica Acta}, volume = {627}, number = {1}, year = {2008}, note = {ISI Document Delivery No.: 358IYTimes Cited: 22Cited Reference Count: 76Maxwell, E. Jane Chen, David D. Y.Sp. Iss. SI}, month = {Oct}, pages = {25-33}, type = {Review}, abstract = {Capillary electrophoresis-electrospray ionization-mass spectrometry has the potential to become a preferred tool for the analysis of biological mixtures and other complex samples. The development of improved interfaces in the past twenty years has been critical in demonstrating the feasibility of this technique. However, a compromise still exists between interfaces that give optimal performance and those that are practical for commercial applications. The first section of this review focuses on the technological advances in CE-ESI-MS as they relate to the key interface features for both sheath-flow and sheathless systems: delivery of the sheath liquid, shaping of the emitter tip, formation of electrical contact, and practicality in terms of ease of use and lifetime. In the second section, we review the fundamental processes that affect interface performance. Because of the complex natures of both capillary electrophoresis and electrospray ionization, flow rate, arrangement of the electrical circuit, electrochemistry, tip geometry and location of electrical contact must all be carefully managed in the design of a successful interface. (C) 2008 Elsevier B.V. All rights reserved.}, keywords = {BEVELED EDGE, capillary electrophoresis, DESIGN, electrospray ionization, EMITTERS, FLOW NANOSPRAY, FUSED-SILICA CAPILLARY, interface development, JUNCTION INTERFACE, LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY, MASS SPECTROMETRY, MICRO-ELECTROSPRAY, SHEATHLESS CAPILLARY, ZONE-ELECTROPHORESIS}, isbn = {0003-2670}, url = {://000259911600003}, author = {Maxwell, E. J. and Chen, D. D. Y.} } @article {2276, title = {Utility of formaldehyde cross-linking and mass spectrometry in the study of protein-protein interactions}, journal = {Journal of Mass Spectrometry}, volume = {43}, number = {6}, year = {2008}, note = {ISI Document Delivery No.: 319PPTimes Cited: 22Cited Reference Count: 54Sutherland, Brent W. Toews, Judy Kast, Juergen}, month = {Jun}, pages = {699-715}, type = {Article}, abstract = {For decades, formaldehyde has been routinely used to cross-link proteins in cells, tissue, and in some instances, even entire organisms. Due to its small size, formaldehyde can readily permeate cell walls and membranes, resulting in efficient cross-linking, i.e. the formation of covalent bonds between proteins, DNA, and other reactive molecules. Indeed, formaldehyde cross-linking is an instrumental component of many mainstream analytical/cell biology techniques including chromatin immunoprecipitation (ChIP) of protein-DNA complexes found in nuclei; immunohistological analysis of protein expression and localization within cells, tissues, and organs; and mass spectrometry (MS)-compatible silver-staining methodologies used to visualize low abundance proteins in polyacrylamide gels. However, despite its exquisite suitability for use in the analysis of protein environments within cells, formaldehyde has yet to be commonly employed in the directed analysis of protein-protein interactions and cellular networks. The general purpose of this article is to discuss recent advancements in the use of formaldehyde cross-linking in combination with MS-based methodologies. Key advantages and limitations to the use of formaldehyde over other cross-linkers and technologies currently used to study protein-protein interactions are highlighted, and formaldehyde-based experimental approaches that are proving very promising in their ability to accurately and efficiently identify novel protein-protein and multiprotein interaction complexes are presented. Copyright (c) 2008 John Wiley \& Sons, Ltd.}, keywords = {ANTIGEN-RETRIEVAL, CHROMATIN IMMUNOPRECIPITATION, COMPLEXES, CROSS-LINKING, FORMALDEHYDE, IDENTIFICATION, IMMUNOHISTOCHEMISTRY, INTERACTION NETWORKS, MASS SPECTROMETRY, PARAFFIN-EMBEDDED TISSUE, protein interactions, PROTEOMICS, review, SURFACE-TOPOLOGY, THROUGHPUT}, isbn = {1076-5174}, url = {://000257176400001}, author = {Sutherland, B. W. and Toews, J. and Kast, J.} } @article {724, title = {Characterization of copper-complexing ligands in seawater using immobilized copper(Il)-ion affinity chromatography and electrospray ionization mass spectrometry}, journal = {Marine Chemistry}, volume = {83}, number = {1-2}, year = {2003}, note = {ISI Document Delivery No.: 743RZTimes Cited: 13Cited Reference Count: 44Ocean Sciences Meeting 2002FEB 11-15, 2002HONOLULU, HAWAII}, month = {Oct}, pages = {47-58}, type = {Proceedings Paper}, abstract = {Electrochemical studies show that copper and other bioactive trace metals are associated almost exclusively with dissolved organic ligands in surface seawater. Some of these ligands may be released by photosynthetic marine organisms to control metal uptake. However, new analytical approaches are needed to determine the chemical composition and ecological significance of these compounds. We have combined immobilized metal-ion affinity chromatography (IMAC) with electrospray ionization mass spectrometry (ESI-MS) to selectively extract and characterize copper-complexing ligands in seawater. Samples taken from British Columbia coastal waters were filtered through mixed cellulose membranes (0.45 mum) using nitrogen overpressure. Compounds with an affinity for copper were then extracted using Cu(II)-IMAC and eluted in acidified seawater. The eluant was monitored using UV absorption (255 nm), which showed that IMAC extracts from river and surface waters contained the highest concentrations of U-V-absorbing organic matter. Fractions were collected and analyzed by flow-injection (FI) negative ion ESI-MS using a custom made XAD-16 column, which gave 82\% recovery and a detection limit of 1.6 pmol for salicylic acid in acidified seawater. Low-molecular-weight compounds containing nitrogen were detected in the IMAC extracts of highest UV absorbance. These compounds followed an elution profile similar to the corresponding UV chromatogram. Measured masses of 265 and 259 Da are consistent with peptides containing, respectively, one thiol and two primary amino groups, characteristics associated with copper-complexing ligands detected in marine algal cultures and surface seawater using other methods. However, the absence of positive ions under experimental conditions suggests that the extracted compounds are predominantly acidic, and may therefore be hydroxamic acids or other nitrogen-containing compounds. The use of alternative resins and FI solvents to improve recovery, increase ionization efficiency, and permit structural (MS/MS) analysis of compounds extracted by IMAC is now being investigated. (C) 2003 Elsevier B.V All rights reserved.}, keywords = {CHROMATOGRAPHY, COMPLEXATION, CU, DISSOLVED COPPER, electrospray ionization, ESTUARINE WATER, iron, LIGANDS, marine environment, MARINE-BACTERIA, MASS SPECTROMETRY, OCEAN, organic compounds, ORGANIC-LIGANDS, PHYTOPLANKTON, SPECIATION, stress}, isbn = {0304-4203}, url = {://000186588500006}, author = {Ross, A. R. S. and Ikonomou, M. G. and Orians, K. J.} } @article {427, title = {Arsenic speciation in whelks, Bucciunum undatum}, journal = {Applied Organometallic Chemistry}, volume = {16}, number = {8}, year = {2002}, note = {ISI Document Delivery No.: 582FYTimes Cited: 6Cited Reference Count: 2510th International Symposium on Natural and Industrial Arsenic of the Japanese-Arsenic-Scientists-SocietyNOV 29-30, 2001TOKYO, JAPANJapanese Arsen Scientists Soc}, month = {Aug}, pages = {458-462}, type = {Proceedings Paper}, abstract = {The arsenic species present in the foot muscle of whelks, Buccinum undatum, collected from Newfoundland, Canada, were characterized by using high-performance liquid chromatography-inductively coupled plasma mass spectrometry. All samples contain high amounts of arsenic, mostly over 100 mug g(-1) (as arsenic, dry weight basis), and one sample contained up to 1360 mug g(-1). These values are considerably higher than those reported in other gastropods. Speciation studies of representative samples revealed arsenobetaine as the major water-soluble arsenic compound, together with trace amounts of an arsenosugar. No inorganic arsenic species were detected in the sample extracts, indicating that consumption of the whelks poses little human risk. Copyright (C) 2002 John Wiley Sons, Ltd.}, keywords = {arsenic, arsenobetaine, arsenosugar, HPLC, ICP-MS, LIQUID-CHROMATOGRAPHY, MASS SPECTROMETRY, SPECIATION, whelks}, isbn = {0268-2605}, url = {://000177340200011}, author = {Lai, V. W. M. and Beach, A. S. and Cullen, W. R. and Ray, S. and Reimer, K. J.} } @article {4852, title = {Antimony species in environmental samples}, journal = {International Journal of Environmental Analytical Chemistry}, volume = {77}, number = {2}, year = {2000}, note = {ISI Document Delivery No.: 335VQTimes Cited: 17Cited Reference Count: 33}, pages = {111-131}, type = {Article}, abstract = {Antimony was extracted from environmental biota samples from Yellowknife, NWT and Meager Creek, BC, Canada. Extraction efficiencies ranged from 0.7 to 37\% for all samples except for a cattail sample, from which 95\% of antimony was extracted. Speciation analysis was carried out by using hydride generation-gas chromatography-atomic absorption spectrometry (HG-GC-AAS). The major antimony species in all samples, including biota extracts and water, was Sb (V). Sb (III) and methylated antimony species were detected in some samples as well. The presence of methylated antimony species in moss from Yellowknife and a water sample from Yellowknife was confirmed by using HG-GC-AAS at a second absorption wavelength, increasing the likelihood that the peaks obtained are due to the presence of antimony compounds. A headspace HG-GC-mass spectrometric (MS) method was developed for the speciation of antimony compounds and this was used to successfully confirm methylantimony species in the headspace following HG of extracts of moss and snail samples from Yellowknife.}, keywords = {ANTIMONY, ATOMIC-ABSORPTION SPECTROMETRY, GENERATION GAS-CHROMATOGRAPHY, HYDRIDE GENERATION, MASS SPECTROMETRY, PERFORMANCE LIQUID-CHROMATOGRAPHY, PLANTS, SCOPULARIOPSIS-BREVICAULIS, snails, SPECIATION, WATERS}, isbn = {0306-7319}, url = {://000088265800002}, author = {Koch, I. and Wang, L. X. and Feldmann, J. and Andrewes, P. and Reimer, K. J. and Cullen, W. R.} } @article {4921, title = {Characterization of dissolved tannins and their metal-ion complexes by electrospray ionization mass spectrometry}, journal = {Analytica Chimica Acta}, volume = {411}, number = {1-2}, year = {2000}, note = {ISI Document Delivery No.: 305EYTimes Cited: 25Cited Reference Count: 51}, month = {May}, pages = {91-102}, type = {Article}, abstract = {Electrospray mass spectrometry was used to characterize metal-complexing ligands derived from tannic acid, a component of natural dissolved organic matter. Complexes formed by tannin ligands with copper and other biogeochemically important metals were identified from the mass-to-charge ratios of the corresponding deprotonated molecular ions, allowing stoichiometry and metal oxidation state to be determined. Ligand ion intensities were proportional to tannic acid concentration, with detection limits on the order of 5 nM for individual compounds in 50:50 water/acetonitrile. The relative abundance of free ligand and complex ions indicated the degree of complexation under different solution conditions (metal concentration, pH, ionic strength). Using tandem mass spectrometry, the structure and principal copper binding site for one of the tannins were also determined, providing unique information with regard to metal complexation by these polyfunctional ligands. The technique can be combined with high performance liquid chromatography for on-line separation of dissolved organic compounds. Results demonstrate the potential of this approach for characterizing the different classes of metal-complexing ligands found in natural waters. (C) 2000 Elsevier Science B.V. All rights reserved.}, keywords = {AFFINITY-CHROMATOGRAPHY, CHROMATOGRAPHY, COMPLEXATION, copper, electrospray ionization, high performance liquid, iron, LIGANDS, MASS SPECTROMETRY, metal-ion complexes, NATURAL ORGANIC-LIGANDS, ORGANIC, PERFORMANCE, PROTEINS, REGIOSELECTIVE MONO-OXIDATION, SPECIATION, STOICHIOMETRY, tannins, TOXICITY, trace metals}, isbn = {0003-2670}, url = {://000086527500011}, author = {Ross, A. R. S. and Ikonomou, M. G. and Orians, K. J.} } @article {4255, title = {Complementary use of capillary gas chromatography mass spectrometry (ion trap) and gas chromatography inductively coupled plasma mass spectrometry for the speciation of volatile antimony, tin and bismuth compounds in landfill and fermentation gases}, journal = {Analyst}, volume = {123}, number = {5}, year = {1998}, note = {ISI Document Delivery No.: ZN568Times Cited: 40Cited Reference Count: 183rd International Symposium on Speciation of Trace Elements in Biological, Environmental and Toxicological SciencesSEP 15-19, 1997PORT DOUGLAS, AUSTRALIAUniv New S Wales, Natl Inst Occupat Hlth, McMaster Univ, Inst Environ \& Hlth, MAFF, CSL, Food Sci Lab}, month = {May}, pages = {815-820}, type = {Proceedings Paper}, abstract = {ICP-MS is very sensitive and has limited matrix effects when used as an element-specific detector for GC in order to identify volatile metal or metalloid species, GC-MS is not very sensitive or selective in the electron ionization (EI) mode, but provides molecular information about volatile species. In this work, an ion trap EI-MS-MS and an ICP-MS system were used as two different detectors for the same GC system to provide complementary information about volatile organometallic species in the complex matrices of landfill and sewage sludge fermentation gases. A simple robust GC separation method with cryotrapping was adequate for the separation of the different metal(loid) containing volatile compounds, and was directly coupled to the ICP-MS system, In addition, gas samples from this GC system were collected in evacuated vials. These fractions were further separated on a capillary column and detected in an ion trap mass spectrometer. For the first time, parent ions, fragmentation patterns, isotopic ratios for Sb and Sn, and MS-MS data were used to identify positively Me3Sb, Me4Sn and Et2Me2Sn in landfill gas and Me3Sb and Me3Bi in fermentation gas.}, keywords = {ELEMENTS, fermentation gas, gas chromatography-inductively coupled, ion trap mass spectrometry, landfill gas, MASS SPECTROMETRY, METAL, MS, organometallics, ORGANOTIN COMPOUNDS, trimethylbismuthine, trimethylstibine, VOLATILE, WASTE DEPOSITS}, isbn = {0003-2654}, url = {://000073658900010}, author = {Feldmann, J. and Koch, I. and Cullen, W. R.} } @article {3642, title = {Reaction of methanol with perfluorotetracyclobuta-1,3,5,7-cyclooctatetraene}, journal = {Journal of Fluorine Chemistry}, volume = {76}, number = {2}, year = {1996}, note = {ISI Document Delivery No.: UA116Times Cited: 4Cited Reference Count: 13}, month = {Feb}, pages = {121-124}, type = {Article}, abstract = {Perfluorotetracyclobuteno-1,3,5,7-cyclooctatetraene (PCOT) is a planar and centrosymmetric molecule which possesses an extraordinary electron affinity due to the planarity of the eight pi-electron system and the cumulative electron-withdrawing effects of the 16 fluorine atoms. An improved method for the synthesis of PCOT and the product resulting from the spontaneous reaction of PCOT with excess alcohol is reported. Crystal structures of the methyl (1) and ethyl (2) derivatives are described.}, keywords = {CRYSTAL, IR spectroscopy, MASS SPECTROMETRY, METHANOL, NMR spectroscopy, perfluorotetracyclobutacyclo-octatetraene, reaction, STRUCTURE}, isbn = {0022-1139}, url = {://A1996UA11600002}, author = {Cullen, W. R. and Rettig, S. J. and Moore, A. E. and Soulen, R. L.} }