@article {1112,
	title = {Chromatographic separation and identification of products from the reaction of dimethylarsinic acid with hydrogen sulfide},
	journal = {Chemical Research in Toxicology},
	volume = {18},
	number = {12},
	year = {2005},
	note = {ISI Document Delivery No.: 004XYTimes Cited: 24Cited Reference Count: 44},
	month = {Dec},
	pages = {1821-1829},
	type = {Article},
	abstract = {The reaction of dimethylarsinic acid (DMA(V)) with hydrogen sulfide (H2S) is of biological significance and may be implicated in the overall toxicity and carcinogenicity of arsenic. The course of the reaction in aqueous phase was monitored, and an initial product, dimethylthioarsinic acid, was observed by using LC-ICP-MS and LC-ESI-MS. Dimethylarsinous acid was observed as a minor product. A second slower-forming product was identified, and the electrospray mass chromatograms for this species produced ions at m/z 275, 171, and 137 in positive mode. To aid in the identification of this slower-forming product, crystalline standards of sodium dimethyldithioarsinate and dimethylarsino dimethyldithioarsinate were prepared and re-characterized by using improved spectroscopic and structural analysis techniques. An aqueous solution of sodium dimethyldithioarsinate produced a single major chromatographic peak that matched the retention time (7.6 min) of the slower-forming product and contained similar molecular ions at m/z 275, 171, and 137 via LC-ESI-MS. The dimethylarsino dimethyldithioarsinate standard produced four aqueous phase species one of which coeluted with the slower forming product. This coeluting peak also produced the identical ESI-MS ions as the slower-forming product of DMA(V) + H2S. ESI-MS/MS experiments conducted on sodium dimethyldithioarsinate in deuterated water produced molecular ions at m/z 276, 173, and 137. Subsequent collisionally activated dissociation (CAD) experiments on m/z 276 did not produce a product ion at m/z 173. These data indicate that two different species are present in solution, while NMR data indicate that only dimethyldithioarsinic acid exists in aqueous solutions. This discrepancy was investigated by conducting NMR studies on the acidic solution of sodium dimethyldithioarsinate after taking this solution to dryness. The resolubilized solution produced a proton NMR signal characteristic of dimethylarsino dimethyldithioarsinate. Therefore, it was concluded that the ESI-MS ion at m/z 275 associated with the slowly forming second reaction product and the sodium dimethyldithioarsinate compound is a product of the ESI desolvation process.},
	keywords = {CRYSTAL-STRUCTURE, DIMETHYLDITHIOARSINATE, GLUTATHIONE, METABOLITE, ORGANIC ARSENIC COMPOUNDS, RATS, REARRANGEMENT, TOXICITY, TRIMETHYLARSINE OXIDE, urine},
	isbn = {0893-228X},
	url = {<Go to ISI>://000234787200005},
	author = {Fricke, M. W. and Zeller, M. and Sun, H. and Lai, V. W. M. and Cullen, W. R. and Shoemaker, J. A. and Witkowski, M. R. and Creed, J. T.}
}
@article {918,
	title = {Arsenic speciation in human urine: are we all the same?},
	journal = {Toxicology and Applied Pharmacology},
	volume = {198},
	number = {3},
	year = {2004},
	note = {ISI Document Delivery No.: 844GRTimes Cited: 26Cited Reference Count: 34},
	month = {Aug},
	pages = {297-306},
	type = {Review},
	abstract = {we studied the arsenic speciation in human urine samples by using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). We investigated the arsenic speciation in the urine collected from nine volunteers during a 3-day period after a meal of blue mussels, Mytilus edulis. We also studied the effect of cooking on the arsenic speciation. Arsenobetaine and dimethylarsinic acid (DMAA) were the major arsenic metabolites found in the urine samples. Significant amounts of unknown metabolites were also detected. The excretion patterns of arsenic from individuals were generally similar except for two subjects. One of whom excreted high amounts of arsenobetaine even though no arsenic-rich food was eaten for 3 days before the experiment. The results reveal that we need a better understanding of the metabolism of arsenic compounds by human. (C) 2004 Elsevier Inc. All rights reserved.},
	keywords = {arsenic, arsenobetaine, arsenosugar, ENVIRONMENT, HPLC, ICP-MS, IDENTIFICATION, INGESTION, LIQUID-CHROMATOGRAPHY, MASS-SPECTROMETRY, METABOLITES, METHYLATED ARSENICALS, mussel, PRODUCTS, TRIVALENT, urine},
	isbn = {0041-008X},
	url = {<Go to ISI>://000223146600007},
	author = {Lai, V. W. M. and Sun, Y. M. and Ting, E. and Cullen, W. R. and Reimer, K. J.}
}
@article {573,
	title = {Velocity-difference induced focusing of xanthine and purine metabolites by capillary electrophoresis using a dynamic pH junction},
	journal = {Chromatographia},
	volume = {57},
	number = {1-2},
	year = {2003},
	note = {ISI Document Delivery No.: 644GETimes Cited: 15Cited Reference Count: 45},
	month = {Jan},
	pages = {87-93},
	type = {Article},
	abstract = {Velocity-difference induced focusing (V-DIF) of analytes by a dynamic pH junction represents a simple yet effective on-line preconcentration method to improve concentration sensitivity in capillary electrophoresis (CE), Differences in buffer type, pH and conductivity between sample and background electrolyte (BGE) segments of the capillary are properties used to optimize purine focusing within a multi-section electrolyte system. This method permits the injection of large volumes of sample (up to 450 nL or about 18\% of capillary length), resulting in over a 50-fold improvement in sensitivity with baseline resolution. The limit of detection (S/N = 3) for xanthine is determined to less than 4,0 x 10(-8) M under optimum conditions when using UV detection. Analysis of micromolor amounts of xanthine in pooled urine is also demonstrated without sample pretreatment. A dual mechanism involving dynamic pH and isotachophoretic modes is proposed to enhance analyte focusing performance when employing buffer pH junctions based on different types of electrolyte co-ions.},
	keywords = {AMPLIFIED SAMPLE STACKING, BIOLOGICAL-FLUIDS, capillary electrophoresis, dynamic pH junction, ELECTROOSMOTIC FLOW, induced focusing, INJECTION, MICELLAR ELECTROKINETIC CHROMATOGRAPHY, NEUTRAL ANALYTES, ON-COLUMN TRANSIENT, purine metabolites, SELF-STACKING, urine, velocity-difference, VOLUME, xanthine analysis, ZONE-ELECTROPHORESIS},
	isbn = {0009-5893},
	url = {<Go to ISI>://000180908900013},
	author = {Britz-McKibbin, P. and Chen, D. D. Y.}
}
@article {5019,
	title = {Separation of free amino acids in human plasma by capillary electrophoresis with laser induced fluorescence: potential for emergency diagnosis of inborn errors of metabolism},
	journal = {Journal of Chromatography B},
	volume = {754},
	number = {1},
	year = {2001},
	note = {ISI Document Delivery No.: 418PQTimes Cited: 44Cited Reference Count: 28},
	month = {Apr},
	pages = {217-228},
	type = {Article},
	abstract = {Free amino acids (AAs) in human plasma are derivatized with 3-(4-carboxybenzoyl)quinoline -2-carboxaldehyde (CBQCA) and analyzed by capillary electrophoresis (CE) with laser induced fluorescence (LIF) detection. The labeling procedure is significantly improved over results reported previously. Derivatization can be completed in 40 min, with concentrations as low as 4x10(-8) M successfully labeled in favourable cases. Twenty-nine AAs (including 2 internal standards) are identified and can be reproducibly separated in 70 min. Migration time RSD values for 23 of these AAs were calculated and found in the range from 0.5 to 4\%. The rapid derivatization procedure and the resolution obtained in the separation are sufficient for a semi-quantitative, emergency diagnosis of several inborn errors of metabolism (IEM). Amino acid profiles for both normal donor plasma samples and plasma samples of patients suffering from phenylketonuria, tyrosinemia, maple syrup urinary disease, hyperornithinemia. and citrullinemia are studied. (C) 2001 Elsevier Science B.V. All rights reserved.},
	keywords = {amino acids, CARNITINE, CHROMATOGRAPHY, inborn errors, urine, ZONE ELECTROPHORESIS},
	isbn = {0378-4347},
	url = {<Go to ISI>://000167900900026},
	author = {Boulat, O. and McLaren, D. G. and Arriaga, E. A. and Chen, D. D. Y.}
}
