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Water Sci Technol

Title:		Inorganic polysulfides' quantitation by methyl iodide derivatization: dimethylpolysulfide formation potential
Author(s):		Goifman A; Ryzkov D; Gun J; Kamyshny A; Modestov AD; Lev O;
Address:		"The Laboratory of Environmental Chemistry, Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"
Journal Title:		Water Sci Technol
Year:		2004
Volume:		49
Issue:		9
Page Number:		179 - 184
DOI:
ISSN/ISBN:		0273-1223 (Print) 0273-1223 (Linking)
Abstract:		"Inorganic polysulfides are important intermediates in the formation of dimethylpolysulfides and possibly other volatile sulfur compounds of environmental significance. Currently, direct determination of these ions in the concentration range of natural systems is practically impossible, particularly under oxic conditions. Polysulfide quantification by derivatization with methyl iodide or d6-methyl iodide is emerging as a valuable alternative method for studies of polysulfide formation in natural systems. This manuscript presents detailed studies aimed at the evaluation of this method. We determined the conversion of the inorganic polysulfides to dimethylpolysulfides by methylation with methyl iodide. Close to 100 per cent of the molar concentration of polysulfide salts were converted to organic polysulfides for very low concentrations of dissolved polysulfide solutions, but only a small recovery was obtained for high concentrations of polysulfide precursors or when the solubility limit was exceeded. The recovery of polysulfides based on the calculated dissolved polysulfide concentration exceeds 1,000 per cent for very low dissolved concentrations of polysulfides. This unexpected dependence is attributed to continuous inorganic polysulfide formation from hydrogen sulfide and sulfur precipitate concurrent with, and in fact driven by, the methylation process"
Keywords:		"Environmental Monitoring/methods Hydrocarbons, Iodinated/*chemistry Methylation Sensitivity and Specificity Solubility Sulfides/*analysis/chemistry Water Supply;"
Notes:		"MedlineGoifman, A Ryzkov, D Gun, J Kamyshny, A Jr Modestov, A D Lev, O eng Research Support, Non-U.S. Gov't England 2004/07/09 Water Sci Technol. 2004; 49(9):179-84"