title: Quantification of arsenic compounds using derivatization, solvent extraction and liquid chromatography electrospray ionization tandem mass spectrometry.
abstract: The difficulty in detecting inorganic arsenic compounds using conventional settings of mass chromatography has led to the use of derivatizing agents to aid in their detection. A recent study indicated that 2,3-dimercaptopropanol (BAL) could be used to derivatize arsenic compounds to make them detectable by LC coupled to UV detector. A speciation analysis method was then developed for arsenic compounds after derivatization using the LC-MS/MS with the aim to improve the sensitivity and specificity. The arsenic compounds were derivatized with BAL before solvent extraction was carried out. The resultant extract was analyzed using the LC-MS/MS. However, our finding showed that BAL, being a thiol, reduced the pentavalent arsenic compounds, As(V) to a trivalent state, As(III). The arsenic metabolites, monomethyl arsonate (MMA) and dimethyl arsenic acid (DMA) could also be reduced by BAL to As(V)- and As(III)-BAL adducts. Despite this, the assay could be used to quantify the total arsenic concentration as a summation of all these adducts, when speciation of individual arsenic species is not required. The developed LC-MS/MS assay was subsequently applied to detect arsenic compounds in rat urine samples after oral administration of arsenic trioxide.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
authors.forename: Meng
authors.initials: M
authors.lastname: Huang
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Wang
authors.forename: Paul C
authors.initials: PC
authors.lastname: Ho
mesh_terms: D000818:Animals; D001152:Arsenicals / Q000032:analysis* / Q000737:chemistry / Q000652:urine; D002614:Chelating Agents / Q000737:chemistry; D002853:Chromatography, Liquid; D004112:Dimercaprol / Q000737:chemistry; D008297:Male; D015394:Molecular Structure; D008970:Molecular Weight; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D016482:Urinalysis; D014867:Water / Q000737:chemistry
chemical_list: D001152:Arsenicals; D002614:Chelating Agents; D014867:Water; D004112:Dimercaprol