Exploiting a gold leaf-based voltammetric sensor for the estimation of firing distance

Abstract

In this study, we present a novel electrochemical approach for firing distance estimation using a gold leaf-based sensor integrated with screen-printed electrodes. This is the first report of employing a gold leaf-based sensor for the voltammetric estimation of firing distance by detecting Pb in gunshot residue (GSR) on fabric targets. The sensor consists of a gold leaf sheet as the working electrode, with carbon and silver/silver chloride screen-printed electrodes serving as the counter and reference electrodes, respectively. Pb(II), a key component of GSR, was extracted from 15 mm fabric discs using manual shaking in nitric acid for 3 min. The extracted solution was analyzed by anodic stripping voltammetry (ASV) with a portable electrochemical system. The Pb(II) signal was then correlated with the firing distance to construct an analytical curve for estimation of shooting distance in the range of 5–60 cm. The resulting mathematical model enables accurate distance estimation. This cost-effective, reagent-free, and field-deployable electrochemical sensor offers a rapid and accessible alternative for forensic firearm investigations.