A highly selective amperometric biosensor array for the simultaneous determination of glutamate, glucose, choline, acetylcholine, lactate and pyruvate

The work was aimed at the development of a biosensor array for the simultaneous determination of six solutes (glutamate, glucose, choline, acetylcholine, lactate, and pyruvate) in aqueous solutions. Enzymes selective for these substrates were immobilized on the surface of amperometric platinum disc electrodes and served as bioselective elements of a biosensor array. Direct enzymatic analysis by the developed biosensors provided high sensitivity to the tested substrates (limits of detection were 1–5 μM). The linear ranges of the biosensors were from 0.001–0.01 mM to 0.2–2.5 mM. The influence of solution pH, ionic strength and buffer capacity on the biosensor responses was investigated; the conditions for simultaneous operation of all the bioselective elements were optimized. The absence of any cross-influence of the substrates of enzymatic systems used was shown as well as a high selectivity of the biosensors and the absence of any impact of interfering substances (ascorbic acid, dopamine, cysteine, paracetamol). The developed biosensor array had good response reproducibility and storage stability. The array is suitable for rapid (0.5–1 min) and simple simultaneous determination of glutamate, glucose, choline, acetylcholine, lactate, and pyruvate in aqueous (biological) samples; furthermore, the creation of a single chip with six sensitive elements is possible as well as the addition of other biosensors. •A biosensor array for neurotransmitter and metabolite determination was created.•It is based on enzymes immobilized on platinum disc electrodes.•Quick response, simplicity, and low cost are advantages of the biosensor array.•The biosensor array can be used for the analysis of aqueous sample composition.