Comparative kinetic study for rate constant determination of the reaction of ascorbic acid with 2,6-dichlorophenolindophenol.
The rate constant k of the reaction of ascorbic acid with 2,6-dichlorophenolindophenol (DCPI) in oxalic acid solutions is determined, by stopped-flow techniques. Four different methods are used to evaluate the results. The values and errors are compared statistically. The average of the rate constant is 56.5 x 10(3) l. mole(-1), sec(-1) and the overall standard deviation is 0.6 x 10(3) l. mole(-1), sec(-1) or 1.0% relative. The pH-dependence of the rate constant suggests that DCPI reacts with undissociated ascorbic acid.
Karayannis
M I
MI
Laboratory of Analytical Chemistry, University of Athens, 104 Solonos Str., Athens, Greece.