Use of p -Chloromercuribenzoic Acid in the Determination of Ascorbic Acid in the Presence of Sulphydryl Compounds

IN certain circumstances hydrogen sulphide, cysteine and related sulphydryl compounds react with 2 : 6-dichlorophenol-indophenol (indophenol) and thus may interfere with the determination of ascorbic acid using this reagent. In view of the known ability of p-chloromercuribenzoic acid to combine with sulphydryl compounds1, the possibility of using this reagent to suppress such interference has been examined.