The collection and identification of thiols and disulphides

Abstract

Following the evolution of sulphur compounds from cultures of marine organisms in methionine solution, the collection of thiols and disulphides in mercuric cyanide and mercuric chloride was studied. The subsequent conversion of the mercaptides and mercury complexes to z,4-dinitrophenyl sulphides was found to be possible by decomposing the mercury compounds with acid and collecting the mercaptan in caustic ethanol and then treatment with 1-chloro-z,4-dinitrobenzene. A method for the chromatography of the n,4-dinitrophenyl sulphides on paraffin-impregnated paper was devised and studied. IntroductionDuring attempts to separate and identify the metabolites of marine organisms cultured with methionine, an odour, closely resembling that of organic sulphur compounds, was 0bserved.l This was also noticed when samples of marine organisms were treated with a solution of 10% caustic soda. These volatile sulphur compounds were collected successfully in mercuric cyanide and mercuric chloride according to the method of Challenger.2 The further identification of the alkali-decomposable precipitate3 from mercuric chloride, by paper chromatography of the regenerated sulphide as the sulphidimine4 was found to be satisfactory. This method of Challenger & Leaver has recently been extended and improved by the use of 9-nitrobenzenesulphonchloramide, NO,*C,H,.SO,N(Cl)Na, instead of chloramine T.5There are, however, few methods, apart from the melting points of the mercaptides of mercury and lead, for the further identification and separation of thiols. The thiols were either given off as thiols from the cultures and decomposition experiments, or were obtained from the acid decomposition of mercury complexes formed in mercuric chloride and mercuric acetate solution from fission of the disulphides.21 3The reaction of thiols with mercuric cyanide leads, it is supposed,2 to the formation of the insoluble complex (RS),Hg and (RS)2Hg.Hg(CN),. By boiling with water3 the mixture is converted to the pure mercaptide which may be recrystallised to give a well defined melting point. If the material for examination consists of mixture of thiols, the separation could only be effected by gas chromatography.In earlier work 1-chloro-z,4-dinitrobenzene was used by Boost and others6 to prepare 3,4-dinitrophenyl sulphides from thiols ; these sulphides were also prepared by Carson & Wong7 from lead mercaptides by refluxing with the reagent named. The latter authorss chromatographed the z,4-dinitrophenyl sulphides on silicic acid and fluorescent zinc sulphide. It was felt, however, that paper chromatography of the z,4-dinitrophenyl sulphide might be more suitable. It was not possible to prepare crystalline z,4-dinitrophenyl sulphides by refluxing 1-chloro-z,4-dinitrobenzene with a mercury mercaptide.The crystalline z,4-dinitrophenyl sulphides were finally prepared, both from the mercury mercaptides and the mercury complex resulting from disulphide fission, by decomposition with acid and aspiration of the acid-free thiol vapours into ethanolic sodium hydroxi...

Chicken Flavor and Aroma, Separation and Identification of Carbonyl and Sulfur Compounds in Volatile Fraction of Cooked Chicken

“…Separate crystals were identifiable microscopically. a light yellow precipitate of 2,4-dinitrophenvl thioether(s) by the method of Folkard and Joyce (5).…”

“…Test for Organic Disulfides. A positive test for organic disulfides was obtained by the sodium chloride precipitation procedure of Folkard and Joyce (5). Reduction of the disulfides to mercaptans by treatment with sodium borohydride (26) resulted in confirmation of the identification by formation of the 2,4-dinitrophenyl thioether(s).…”

“…of 8.V HC1 in a 1 X 4 cm. reaction trap (5). Tests for disulfides and mercaptans were made using absorption trains and reagents as described by Folkard and Joyce (5).…”

“…reaction trap (5). Tests for disulfides and mercaptans were made using absorption trains and reagents as described by Folkard and Joyce (5). For mercaptans, absorption traps containing mercuric chloride solution (3% w./v.)…”

Atmospheric composition in an enclosed swine production building

“…Quantitative analysis of the gases is easily performed if standards are developed.Disulfides can be collected by bubbling the odorous vapors through a reagent trap containing mercuric acetate (4% W/V). A white precipitate is formed by the addition of sodium chloride which can be used to regenerate the gases for chromatographic analysis(55).EXPERIMENTAL General The experimental portion of this research wcs conducted in the AiSI-iSU Swine Atmosphere Research Building, a laboratory cooperatively supported by American Iron and Steel institute and Iowa State University. The building contained two animal chambers, an air-mixing chamber, a mechanical and feed room, and a laboratory…”