The Development of Sensitive and Selective Potentiometric Biosensor for Urea Assay

The development of the biosensor as a step to obtain analytical instrument for urea is explained in this study. The aim of this research is to obtain sensitive and selective potentiometric biosensor for urea assay in clinical sample. The study was conducted through preparation of an enzyme electrode with immobilisation of urease onto the tungsten wire by using matrix polymer, followed by interfacing the sensing device vs Ag/AgCl with voltmeter that was connected with Powerlab for data aquisition. The presence of urease in the sensing device is catalytically converted the urea to ammonium ion and bicarbonate which results in the potential change in electrochemical cell. The wide linearity range for urea standard solution was obtained (0.1 - 10 mM urea) with slope 42.7 mV per-decade urea concentration (r2 = 0.993). The urea biosensor gives sensitive response to urea where the detection a limit was 0.1 mM urea. A very fast analytical response was achieved that was only taken four minute per-sample. The potentiometric urea biosensor developed in this study is promising since the instrumentation component is relatively inexpensive and can be modified to an portable mini biosensor.