Simultaneous polarographic chemometric trace analysis of pyrazine and its methyl derivatives

Abstract The polarograms of mixtures of the cocoa flavor compounds, pyrazines, consist of overlapping peaks. This generally precludes the direct analysis of these compunds without prior separation. In this paper, polarographic conditions for the analysis of up to four component mixtures of pyrazines present at trace levels (150 ppb‐1 ppm) were investigated using differential pulse polarography (DPP) at a static mercury drop electrode (SMDE). A series of pyrazine mixtures were analyzed at pH 4.8 (phosphate/citric acid buffer) and the results were interpreted using partial least squares (PLS), principal component regression (PCR), and multiple linear regression (MLR) chemometric routines. In each case an orthogonally designed training set was used to facilitate predictions. The PLS and the PCR models produced acceptable results with recoveries, in general, being in the 97–104% range and RSD in the 4–10% range depending on the nature and complexity of the mixture analyzed.