Curve resolution and quantification of pyrazines by differential-pulse polarography using a Kalman filter approach

A simple and rapid method for the simultaneous polarographic determination of pyrazine and its methyl derivatives (up to four components) has been developed. The potential was scanned from –600 to – 1000 mV by differential-pulse polarography. A solution containing a phosphate—citric acid buffer and a potassium chloride supporting electrolyte (pH 4.8; l= 0.5 mol l–1) was used. Under these conditions, high measurement sensitivities for the pyrazines were achieved. The pulse amplitude, scan rate and the time interval were –50 mV, –10 mV s–1 and 600 ms, respectively. However, because of severe overlap of the polarograms for pyrazines under these conditions, the Kalman filter method was used for the determination and curve resolution of individual components. In contrast to conventional implementation of the Kalman filter, a measurement function derived from a known set of mixed pyrazines was found to yield the best results in this work.