Procedure 23 Determination of total phenols in wastewaters using a biosensor based on carbon paste modified with crude extract of jack fruit (Artocarpus integrifolia L.)

Abstract

Publisher Summary This chapter presents a procedure to construct and apply a biosensor based on capric acid/graphite powder modified with crude extract of jack fruit (Artocarpus integrifolia L.) as the source of polyphenol oxidase to determine total phenols in wastewaters by differential pulse voltammetry. To prepare the biosensor enzyme crude extract, the graphite powder, and fatty acid are mixed. First, graphite powder is mixed with enzyme source in a mortar for 20 min, after that fatty acids are added to obtain homogenous mixture. Paste is packed into the tip of a 1mL insulin plastic syringe and inserted into a copper wire to obtain the external electric contact. The total phenols concentration present in the samples is determined by differential pulse voltammetry using the standard addition method. After studies of different kinds of fatty acids, it was observed that developed biosensor based on graphite/capric acid modified with polyphenol oxidase from jack fruit crude extract was sensitive, of easy construction and reliable in determining total phenols in wastewater samples. The results of the proposed method agreed at the 95% confidence level with the results obtained using the standard method procedure.