Abstract
. The kinetics of the coloured reaction between ninhydrin and nickel(II)-tryptophan complex have been investigated spectrophotometrically in aqueous as well as in micellar solutions. The reaction follows first- and fractional-order kinetics with respect to [Ni(II)-trp(+)] and [ninhydrin], respectively, both in the absence and in the presence of cationic micelles. The results are discussed in terms of pseudo-phase model. The values of k(m), K-S, K-N, E-a, DeltaH(#) and DeltaS(#) have been calculated. Presence of NaCl, NaBr, NaNO3 and Na2SO4 respectively shows a decrease (except with Na2SO4) in the rate followed by an increase in the rate and it, is found that tightly bound/incorporated cations are most effective.