S. Bijlsma et al., Estimating reaction rate constants: comparison between traditional curve fitting and curve resolution, ANALYT CHIM, 419(2), 2000, pp. 197-207
A traditional curve fitting (TCF) algorithm is compared with a classical cu
rve resolution (CCR) approach for estimating reaction rate constants from s
pectral data obtained in time of a chemical reaction. In the TCF algorithm,
reaction rate constants an estimated from the absorbance versus time data
obtained from selective wavelengths. In this case, wavelengths are selected
at which mainly one species is absorbing in time. In CCR, pure spectra of
reacting absorbing species and the reaction rate constants are estimated si
multaneously.
Both TCF and CCR have been applied to experimental data. The reaction rate
constants and the individual pure spectra of the reacting absorbing species
were estimated simultaneously from the UV-VIS spectra taken in time of the
two-step biochemical consecutive reaction of 3-chlorophenylhydrazonopropan
e dinitrile with 2-mercaptoethanol. This reaction was performed under secon
d order and pseudo-first order conditions. For both conditions, the signal-
to-noise ratio was approximately the same. However, if second order conditi
ons are chosen, the first reaction step is very slow, which results in smal
l absorbance differences in time. For the pseudo-first order dataset, the b
est precision of the reaction rate constant estimates has been obtained wit
h TCF For the second order dataset, CCR performed the best with respect to
the precision of the reaction rate constant estimates. (C) 2000 Elsevier Sc
ience B.V. All rights reserved.