Polyaniline-nanofiber-modified screen-printed electrode with intermediate dye amplification for detection of endocrine disruptor bisphenol A

Abstract

We develop a bisphenol A (BPA) detection sensor using a laccase-immobilized polyaniline (PANI)-doped screen-printed electrode (SPE). BPA detection is carried out by immobilizing laccase on a 4-mm-diameter working electrode. When laccase is immobilized on the PANI/SPE, the activity of the enzyme varies according to the immobilization method. After immobilizing the enzyme on the PANI/SPE, we perform cyclic voltammetry measurements with different BPA concentrations. The detection range and the response time for BPA detection are found to be 1 ppb to 1 ppm and ~100 s intervals, respectively. In the study, the electrode potential is varied from 2 to -2 V at a scan rate of 300 mV/s, and a potential of -1.175 V is applied. In order to increase the sensitivity of laccase/PANI/SPE, we perform experiments with the addition of dyes that are used to transfer electrons quickly at the stage of immobilization. Toluidine blue, Reactive Red 120, and bromothymol blue are used as electron transfer mediators. The linear detection range of the laccase/PANI/SPE is found to be 1 ppb to 10 ppm and the lower detection limit is 0.01 ppb. We use amperometry to observe the change in current with change in the BPA concentration over time.