Fabrication of efficient and selective total arsenic sensor using the hybrid materials modified carbon paste electrodes

Abstract

The aim of this communication is to develop a robust electro-analytical tool for low level detection of total arsenic from aqueous solutions at neutral pH conditions. Hybrid materials were obtained using the natural clay. Further, the carbon paste electrode (CPE) was modified with the hybrid materials and employed in the detection of total arsenic(V). The arsenic(V) was detected prior to chemically reduced to As(III). pH dependence electrochemical behavior of reduced arsenic(V) was obtained at a wide range of pH2.0 to 10.0. A characteristic reduction peak for arsenic was obtained using the hybrid materials-modified CPE at an applied potential of around 0.8V. Concentration dependence studies were conducted for the arsenic(V) by increasing the arsenic(V) concentration from 5.0 to 40.0μg/L. A significant increase in the reductive current was measured around potential 0.80V using the modified CPEs. Regression line was obtained between the studied concentration of arsenic(V) and cathodic peak current values. Further, the detection limit (DL) and quantification limit (QL) was obtained for the arsenic(V) using hybrid materials modified CPEs. The DL values were found to be 2.214, 1.502 and 1.408μg/L for the materials BCH (HDTMA-loaded bentonite), LCH (HDTMA-loaded local clay) and LCAH (aluminium pillared-HDTMA-loaded local clay)-modified CPEs, respectively. The ten-fold excess of several interfering ions (Cd(II), Pb(II), Cu(II), Mn(II), Fe(III), EDTA, glycine and PO43−) were studied in the detection of As(V). Similarly, the tap water was spiked with the arsenic(V) and separately studied for the detection of arsenic(V) from aqueous solutions.