A modified electrode for the electrochemical detection of biogenic amines and their amino acid precursors separated by microchip capillary electrophoresis

作者：Dossi Nicolo; Toniolo Rosanna; Pizzariello Andrea; Susmel Sabina; Bontempelli Gino^*

来源：Electrophoresis, 2011, 32(8): 906-912.

DOI：10.1002/elps.201000690

• Biogenic amines
• Electrochemical detection
• Microchip electrophoresis
• Mixed-valent ruthenium oxide/hexacyanoruthenate films
• Modified electrodes

The use of a mixed-valent ruthenium oxide/hexacyanoruthenate polymeric film electrochemically deposited onto glassy carbon electrodes is proposed here for the detection of biogenic amines and their amino acid precursors, following their separation by microchip capillary electrophoresis. The ability of this ruthenium coating to electrocatalyze the oxidation of aliphatic and heterocyclic amines, as well as their amino acid precursors, was checked by using ethanolamine, tryptamine and tryptophane as prototype compounds and adopting a 25 mM sulphuric acid as the electrolyte in the detection cell, where a constant potential of 1.05 V versus Ag/AgCl, 3M KCl was applied to the modified working electrode. Optimization of parameters affecting both detection and separation steps led to satisfactory separations when performed by using a 20 mM phosphate running buffer (pH 2.5) and applying a high voltage of 2.5 kV both in the separation and in the electrokinetic injection (duration 4 s). The recorded peaks were characterized by good repeatability (RSD <= 3.6%), high sensitivity and a wide linear range. Detection limits of 23 mu M (1.4 mg/L), 27 mu M (4.3 mg/L) and 34 mu M (6.8 mg/L) were inferred for ethanolamine, tryptamine and tryptophane, respectively. The approach proposed here was also applied for the analysis of some double malt dark beers spiked with a controlled amount of the analytes considered.

• 出版日期2011-4