2ND-ORDER TENSORIAL CALIBRATION FOR KINETIC SPECTROPHOTOMETRIC DETERMINATION

Kinetic-diode array spectrophotometric detection, as well as other mul tichannel techniques when used in non-equilibrium conditions, constitu te second-order instrumentation. The second-order response provided wi ll be bilinear, under certain conditions even trilinear, thus allowing the use of the generalized rank annihilation method (GRAM) and the tr ilinear decomposition method (TLD). Both numerically simulated and exp erimental data were used to evaluate the performance of these calibrat ion techniques. The conditions in which the 'second-order advantage' ( the possibility of quantifying the analytes in the presence of unknown reactions or interferences) is preserved were investigated. The coupl ing reaction of diazotized sulfanilamide with p-, o- and m-amino benzo ic acid, and with orciprenaline, to give azodyes was monitored. Binary mixtures of these substrates with different values of the rate consta nt ratio, and with various degrees of spectral overlap, were resolved. The advantages and limitations of higher-order data analysis techniqu es such as GRAM and TLD for the treatment of second-order kinetic data are discussed.