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APPLICATIONS OF CHEMICAL REACTIONS FOR THE DETERMINATION OF TRACE ORGANICS VIA FUNCTIONAL GROUPS
Abstract
Part I: Indirect determination of trace Organic Functional Groups Via Atomic Absorption Spectroscopy. Three indirect analysis techniques for the determination of isothiocyanates, dialkyl disulfides, and carbonyls have been developed. The isothiocyanate functional group is determined by conversion of the isothiocyanate to the substituted thiourea in an ammoniacal solution. The thiourea is desulfurized with a silver amine reagent, producing a silver sulfide precipitate. The precipitate is isolated by filtration, digested in acid, and diluted in an aqueous solution. The silver content is determined by Atomic Absorption Spectroscopy (AAS). The technique has a 0.5 - 20.0 micromole working range with a 2-4% relative standard deviation. The dialkyl disulfide is determined by reduction of the disulfide in ammoniacal sodium sulfite at 50(DEGREES). The resultant mercaptide is precipitated as the silver salt, isolated by filtration, dissolved, and determined by AAS. The technique has a 1.0 - 10.0 micromole working range with a 4-8% relative standard deviation. The carbonyl functional group was determined by treating the carboxyl with hydroxylamine hydrochloride to form the oxime product and acid. A measured quantity of ammonia was added as a proton scavenger to force the reaction to completion. The excess ammonia was determined by adding a nickel dimethyl glyoxime solution to both the sample and blank. The change in nickel concentration (from the isolated precipitate) is proportional to the carbonyl content. The nickel was determined by AAS. The technique has a working range of 1.0 - 10.0 micromoles with a 4-8% relative standard deviation. Part II: Immobilized Functional Groups For The Selective Concentration Of Trace Organics. Three different types of functional groups have been immobilized on insoluble supports for the purpose of selectively concentrating trace organics from aqueous and non-aqueous media via functional group reactions. A bis-dianilino ethane functional group was immobilized on a polyacrylate support which was selective for aldehydes in the presence of ketones. The capacity of the resin for various aldehydes was examined. The condensation product, a tetrahydroimidazole, may be acid hydrolyzed to the diamine and the original aldehyde compound. This reaction is employed to recover the sequestered compound. Several hydrazine related functional groups were examined to evaluate their utility as immobilized functional groups for carbonyl concentrating procedures. Four functional groups were evaluated. Carbazide, semithiocarbazide, acid hydrazide, and hydrazine resins were prepared. The semithiocarbazide resin was found to be the most efficient for carbonyl uptake. An isothiuronium salt was immobilized on a polystyrene backbone for the selective reaction with carboxylic acids. The resin was evaluated on the basis of batch equilibration studies, reaction kinetic studies, and column concentration/recovery studies. Solutions of 80 ppb of carboxylic acids were quantitatively recovered with a 100 fold concentration. The intent of this work was to develop novel functional group analysis techniques which may be employed at trace level concentrations.
Subject Area
Analytical chemistry
Recommended Citation
LONGMOORE, KENNETH JOSEPH, "APPLICATIONS OF CHEMICAL REACTIONS FOR THE DETERMINATION OF TRACE ORGANICS VIA FUNCTIONAL GROUPS" (1981). Doctoral Dissertations Available from Proquest. AAI8118017.
https://scholarworks.umass.edu/dissertations/AAI8118017