Three simple, rapid, and accurate methods of determining ascorbic acid In samples of the microgram level have been described. The ascorbic acid was determined spectrophotometrlcally at 336 nm, via a decrease In absorbance In 7 X 10"4 M tetrachlorobenzoqulnone (chloranll) In 80% acetonewater (v/v) at room temperature. Visual and potentlometrlc

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The kinetics of oxidation of 1-propanethiol by 2,6-dichlorophenolindophenol have been studied in acetone–water medium and in the presence of phosphate buffer. The principal reactants interact in a molar ratio of 2:1 forming disulphide and dihydroindophenol. The reaction follows second order kinetics in indophenol while the order is unity in thiol. The rate increases linearly on increasing [H+]. The rate of oxidation increases on increasing the ionic strength as well as the dielectric constant of the reaction system. The addition of reaction products has no effect on the rate. Activation parameters have been evaluated and a suitable mechanism consistent with kinetic data is suggested.