Simple, selective and fast detection of acrylamide based on glutathione S-transferase

Acrylamide (AA) is a toxic compound formed in thermally prepared foods by Maillard reaction. Besides foods, AA may be found in cosmetic products as an impurity of the widely-used non-toxic polyacrylamide. We present a novel, fast and selective detection method based on the amperometric monitoring of the coupling reaction between reduced glutathione (GSH) and AA catalyzed by glutathione S-transferase (GST) to produce an electrochemically inactive compound. We have used electrodes modified with cobalt-phthalocyanine to monitor the decrease of GHS concentration at +300 mV. Our system is simple, does not require supplementary substrates such as 1-chloro-2,4-dinitrobenzene (CDNB) nor have disadvantageous competitive kinetics characteristic to inhibition like signals. Using the optimum concentration of 100 μM GSH we have obtained a linear calibration graph from 7 to 50 μM AA and a limit of detection of 5 μM AA. The method is not affected by interfering compounds usually found in foods and was applied for real sample analysis.