1993 Volume 9 Issue 2 Pages 207-211
Coenzyme pyrroloquinoline quinone (PQQ) was electrochemically detected with high sensitivity and high selectivity by employing its redox catalytic function in reversed-phase high-performance liquid chromatography. This catalytic reaction involves oxidative decarboxylation of glycine by PQQ and the reoxidation of the reduced PQQ by Fe(CN)63- to accumulate Fe(CN)64-, of which the electrochemical detection allows amplified detection of PQQ. Increase by two orders of magnitude of the current was achieved as compared with a direct reductive detection, at a reaction time of 3min and a reaction temperature of 25°C. The detection limit was 0.2pmol (10-8M, 20μl). The present method was applied to quantification of PQQ in table vinegar, milk, and swine serum.