A novel conductometric biosensor based on hybrid organic/inorganic recognition element for determination of L-arginine

A highly accurate conductometric biosensor for determination of L-arginine (L-arg) in the real samples with the complex sample matrices was developed by co-immobilization of arginase, urease and the ammonium-sensitive zeolite clinoptilolite (Clt). The biosensors with different mutual arrangements of the enzyme component and zeolite on the sensitive surface of the gold interdigitated electrodes were studied and compared. The studies showed that the biosensor containing the primary layer of Clt deposited on the electrode surface followed by arginase and urease co-immobilized as the secondary layer has the most advantageous analytical characteristics compared to the biosensors based on other configurations of the bioselective membrane. In particular, for this biosensor they were as follows: sensitivity 9.61 ± 0.01 μS/mM, limit of detection 5 μM, linear range 0–280 μM and dynamic range 0–15 mM. The biosensor demonstrated high operational stability and storage stability. The effect of solution parameters (pH, ionic strength and buffer capacity) on the biosensor sensitivity was studied. Finally, we used the developed biosensor for quantification of L-arg in the food samples. The results of the biosensor analysis were compared with the control method (ion chromatography). The data of the biosensor method demonstrated high correlation with the reference data (R = 0.96).