Background:

An electrochemical sensor is a device that measures the concentration of a specific substance in a solution by converting the chemical energy of a substance into an electrical signal. Electrochemical sensors are widely used in various fields such as environmental monitoring, medical diagnosis and industrial processing. This article will provide an overview of electrochemical sensors, including their operating principles, types and applications.

The working principle of electrochemical sensor 

Electrochemical sensors are based on the principles of electrochemical cells, which are systems that convert chemical energy into electrical energy. An electrochemical cell consists of two electrodes, an anode and a cathode, separated by an electrolyte. The anode is the electrode where oxidation occurs, while the cathode is the electrode where reduction occurs. When a potential difference is applied between electrodes, an electric current flows through the cell.

In an electrochemical sensor, the target substance (analyte) is oxidized or reduced on the surface of a working electrode coated with a specific material that is selective to the analyte. As a result, an electric current is generated proportional to the concentration of the analyte in the solution. The current is then measured through an external circuit and the concentration of the analyte is determined.

Types of electrochemical sensors 

There are several types of electrochemical sensors, each designed to detect a specific analyte or group of analytes. The most common types of electrochemical sensors include:

Amperometric sensors: Amperometric sensors are used to detect analytes for oxidation or reduction reactions. These sensors consist of a working electrode, a reference electrode and an electrolyte. The working electrode is usually made of a precious metal, such as platinum or gold, and coated with a specific material that is selective for the analyte. When a potential difference is applied between the electrodes, the analyte is oxidized or reduced on the surface of the working electrode, producing a current proportional to the concentration of the analyte in the solution.

Potential sensors: Potential sensors are designed to detect analytes that cause changes in the potential difference between two electrodes. These sensors consist of a working electrode and a reference electrode separated by an electrolyte. The working electrode is coated with a specific material that is selective to the analyte. When the analyte interacts with the working electrode, it causes a change in the potential difference between the working electrode and the reference electrode, which is measured by an external circuit.

Conductance sensors: Conductance sensors are used to detect analytes that cause changes in the conductivity of a solution. These sensors consist of two electrodes separated by an electrolyte. When the analyte interacts with the electrode, it causes a change in the conductivity of the solution, which is measured by an external circuit.

Application of electrochemical sensor 

Electrochemical sensors have a wide range of applications, including:

Environmental monitoring: Electrochemical sensors are used to monitor pollutant levels in the environment, including gases, liquids and solids. These sensors are commonly used to detect toxic gases such as carbon monoxide, nitrogen dioxide and sulfur dioxide, which can have serious health effects if they are present in high concentrations.

Medical diagnosis: Electrochemical sensors are used in medical diagnosis to detect the presence of biomolecules in body fluids such as blood, urine and saliva. These sensors are commonly used to detect glucose, cholesterol and other biomolecules that indicate a variety of diseases.

Industrial processing: Electrochemical sensors are used in industrial processing. Monitoring chemical concentrations in various processes such as electroplating, metal refining and wastewater treatment. These sensors are often used.