The composition of maja leaf extract (Aegle marmelos) and silica gel for urea biosensor

In this work, we used Indonesian-naturalized plant, Maja (Aegle marmelos) leaf extract instead of urease enzyme for urea sensor. Maja leaf extract, silica gel, and paraffin were mixed until homogenous, and then pasted to the tip of the silver wire, which was tightly covered by glass tube to assemble a silica gel-Maja leaf extract modified silver electrode. Cyclic voltammetry showed that cathodic and anodic current signals were observed at 0.4 V and 0.625 V, respectively. The optimum composition of silica and Maja leaf extract were also investigated. The best response was observed at the paste composition ratio of silica gel and paraffin of 3: 2, with 0.05 gr total weight and 0.03 gr Maja leaf extract.