Electroanalysis of As(III) and Hg(II) Ions with Hot Microelectrodes

Globally, environmental pollution has been a source of concern. Pollutants, such as heavy metals, constantly build up in the environment due to industrialization, resulting in harmful and sometimes irreversible changes to ecosystems. These hazardous heavy metals enter the human body mostly via food and water, causing a variety of health disorders ranging from mild health problems to cancer. Heavy metals may also interact substantially with certain enzymes, resulting in modifications to their proper functioning and toxicological effects on living organisms. Traditional approaches to the detection of toxic heavy metal ions need the use of costly or cumbersome tools and sophisticated processes and handling. To determine acceptable levels of heavy metals, a simple, rapid, and reliable method for assessing the toxicity of drinking water and food is required. For a sustainable and healthy socioeconomic development, therefore, water monitoring and management of water quality are essential. Described herein is a rapid, reliable, and reproducible technique for detecting trace heavy metals such as arsenic and mercury in water. The approach consists of applying a hot microelectrode in conjunction with square wave voltammetry without altering the surface of the electrode.In Chapter I, the historical context and environmental effects of heavy metal contamination are explained in brief. The current state of the art for detection of As3+ and Hg2+ ions are discussed here.In Chapter II, the conventional methods for detecting heavy metal ion are discussed. Also discussed is the mechanism of heating of the heated electrode and square wave voltammetry.In Chapter III, the experimental design, including materials, instruments, and the various voltammetric methods applied in the investigation, is described in general terms.In Chapter IV, the method's theoretical component is discussed. It comprises the various modules and equations used in the creation and simulation of models in the COMSOL Multiphysics software package.In Chapter V, the detection technique for arsenic (III) ion is presented in detail. This contains the whole experimental procedures and outcomes, as well as supporting material. This paper reports using ac polarized hot microelectrodes to detect arsenic (III) at quantities substantially below EPA limits (130 nM) using LSV and SWV. By evaluating a real-world sample of tap water spiked with As(III), this study demonstrates that hazardous arsenic may still be detected under realistic settings with the method.In Chapter VI, we examine the method developed to detect mercury (II) ion. The ac heating waveform (90 MHz, 23 dBm) was delivered during a 120 s deposition period, following which elemental mercury was stripped by LSV or SWV at room temperature. We detected 5 nM Hg(II) using SWV stripping; the LOD was 0.94 nM. Theoretical comparison was also done between hot-disk and hot-wire technologies at identical electrode temperature (319 K).