A chemical sensor is a vital device used to convert chemical information, derived from either a chemical reaction or a physical property of the system under investigation, into an analytically useful signal. The International Union of Pure and Applied Chemistry has defined chemical sensors as devices that can transform chemical information into a measurable signal. Chemical sensors consist of two main functional units -the receptor and the transducer. The receptor, also known as the chemical recognition system, is responsible for providing the sensor with a high degree of selectivity for the analyte being measured. On the other hand, the transducer part is responsible for the sensitivity of the device and transforms the signal from the output domain of the recognition system into an output signal that can be converted into useful data. One popular type of chemical sensor is the electrochemical sensor, which employs physical and chemical changes to generate measurable electrical signals such as potential, current, or resistance changes. An electrochemical sensor typically consists of a sensing electrode, a counter electrode, and a reference electrode. The sensing electrode is usually modified with various polar materials to improve the sensor's detection limit and sensitivity. Electrochemical sensors are widely used to analyze the content of treated samples, as they can provide accurate measurements of chemical compounds in different environments. Currently, the most widely used electrochemical methods for detecting heavy metals include voltammetry, spotentiometry, and conductometry.