Design of a miniaturized multisensor chip with nanoband electrode array and light addressable potentiometric sensor for ion sensing

Abstract

Herein, we present a novel miniaturized multisensor chip integrated with a nanoband electrode array (NEA) for lead and copper detection and a light addressable potentiometric sensor (LAPS) for pH sensing. By this means, pH information could be provided before electrochemical analysis to ensure high performance in heavy metal quantification due to the significant effects of solution acidity on electrochemical analyses. The fabrication processes of the multisensor chip are described in detail and the electrochemical behaviour of NEA was characterized using cyclic voltammetry in sulfuric acid and acetate buffer. For the detection of lead and copper qualitatively and quantitatively, square wave anodic stripping voltammetry (SWASV) was applied with the standard addition method. Deposition potential and deposition time were optimized to be −0.6 V and 120 s, respectively. NEA exhibited a sensitivity of 0.510 μA pbb⁻¹ and 0.678 μA ppb⁻¹ towards lead and copper, respectively, with high correlation coefficients. The repetitive and long-term experiments also demonstrated the good reproducibility and stability of NEA in heavy metal detection. Moreover, the silicon nitride modified LAPS showed a pH sensitivity of 56.49 mV pH⁻¹ with a high correlation coefficient of 0.9999. The reproducibility of LAPS was also investigated and a deviation of less than 2 mV was obtained in both the samples. These results indicate that the miniaturized multisensor chip demonstrates good electrochemical performance in heavy metal and pH sensing.