Publication details

Biosensor for determination of carboxylic acids in wines based on the inhibition of sarcosine oxidase



Year of publication 2010
Type Article in Periodical
Magazine / Source Microchimica Acta
MU Faculty or unit

Faculty of Science

Field Biochemistry
Keywords Biosensor; Sarcosine oxidase; Carboxylic acid; Wine;
Description The flow-through amperometric biosensor is presented for determination of carboxylic acids. It is based on two sensor layers that are deposited on a platinum electrode. The inner layer serves to eliminate interferences by limiting diffusion of electrochemically active substances such as ascorbic acid. This layer is electro-polymerized using an equimolar mixture of o-phenylenediamine and resorcinol. The outer layer is prepared by cross-linking the enzyme sarcosine oxidase and bovine serum albumin using glutaraldehyde. The formation of enzymatically produced hydrogen peroxide is monitored at 600 mV vs. an Ag/AgCl reference electrode. The addition of carboxylic acids causes competitive inhibition of the enzyme and a decrease in signal. The assay was optimized for determination of carboxylic acids in wine samples. Following 10-fold dilution, most samples contain 1-10 mM individual carboxylic acids and thus a 5 mM concentration of sarcosine was chosen as being optimal for competition.
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