Enhanced sensitivity and separation for simultaneous determination of tin and lead using paper-based sensors combined with a portable potentiostat

Abstract

Due to similar properties in the electroanalysis of tin (Sn(II)) and lead (Pb(II)), the voltammograms of tin and lead overlap and it is difficult to simultaneously determine these two metals. Herein, we develop a simple fabricated sensor based on a bismuth nanoparticle-modified screen-printed graphene electrode (BiNP/SPGE) on a paper-based analytical device (PAD) for the simultaneous determination of Sn(II) and Pb(II) and combine it with a portable potentiostat. To overcome crossing interference, the use of hexadecyltrimethylammonium bromide (CTAB) can provide improved separation and enhanced sensitivity for Sn(II) and Pb(II) detection in oxalic acid as a supporting electrolyte while using square-wave anodic stripping voltammetry. Under optimal conditions, the linear range of both metals was determined to be 10–250 ng mL−1, and the calculated limit of detection (3SD/slope) was 0.26 ng mL−1 and 0.44 ng mL−1 for Sn(II) and Pb(II), respectively. This sensor was also applied to simultaneously determine Sn(II) and Pb(II) in canned food samples. The results obtained from the portable potentiostat were similar to the results obtained by a standard method. Therefore, the proposed device can be further improved for the realization of a rapid on-site detector for Sn(II) and Pb(II) detection in real samples.