J. Anal. Chem., in press (1997)
ABSTRACT. Indicator tubes for the determination of reducing agents in solutions have been proposed. The interaction of ionic associations of tiazine dyers (methylene blue, toluidine blue) with triiodide with reducing agents (thiosulfate, sulfite, diethyldithiocarbaminate, ethylxantoginate, and ascorbic acid) in solution have been studied. Procedures for the determination of the total content of reducing agents and ascorbic acid have been elaborated. The effects of the diameter of an indicator tube, the flow rate, and the concentration of Triton X-100 on the length of the colored zone have been studied. The procedures have been used to determine of total content of reducing agents in waste waters and ascorbic acid in fruit juices.