MULTICOMPONENT KINETIC DETERMINATION OF LANTHANIDES WITH STOPPED-FLOW, DIODE-ARRAY SPECTROPHOTOMETRY AND THE EXTENDED KALMAN FILTER

The application of the extended Kalman filter to multicomponent kineti c data is described. The method is based on obtaining data at multiple wavelengths over time using a linear photodiode array detector. The e xtended Kalman filter is used to process the data obtained. It is show n that accurate results can be obtained even if the estimated value of the rate constant is not completely accurate or reproducible. No pH, ionic strength, or temperature controls were used in testing the chemi cal system. A system of three lanthanides reacting with 4-(2-pyridylaz o)resorcinol (PAR) was used. Accurate estimates of concentrations were obtained even though the relative rate constants for the reactions of La, Pr, and Nd with PAR were 1:1.7:1.9, and a high degree of spectral overlap is present.