CURVE RESOLUTION AND QUANTIFICATION OF PYRAZINES BY DIFFERENTIAL-PULSE POLAROGRAPHY USING A KALMAN FILTER APPROACH

A simple and rapid method for the simultaneous polarographic determina tion of pyrazine and its methyl derivatives (up to four components) ha s been developed. The potential was scanned from -600 to -1000 mV by d ifferential-pulse polarography. A solution containing a phosphate-citr ic acid buffer and a potassium chloride supporting electrolyte (pH 4.8 ; I = 0.5 mol l-1) was used. Under these conditions, high measurement sensitivities for the pyrazines were achieved. The pulse amplitude, sc an rate and the time interval were -50 mV, -10 mV s-1 and 600 ms, resp ectively. However, because of severe overlap of the polarograms for py razines under these conditions, the Kalman filter method was used for the determination and curve resolution of individual components. In co ntrast to conventional implementation of the Kalman filter, a measurem ent function derived from a known set of mixed pyrazines was found to yield the best results in this work.