Recent advances in miniaturized electrochemical analyzers for hazardous heavy metal sensing in environmental samples

Despite the significance of the environment for human subsistence, many daily activities and industrial processes introduce numerous pollutants, which may result in environmental damage and pose a substantial risk to human health. To address these issues, the rapid and efficient screening of pollutants such as heavy metals (HMs) in environmental matrices is highly desirable. Electrochemical techniques, particularly electrochemical sensors (screen printed, paper based, and laser induced graphene based electrodes) have considerable potential for the on-site screening of HM pollutants in complex sample matrices owing to their high sensitivity, long-term stability, low cost, compact instrumentation (onsite analysis), simple sample handling requirements, and high accuracy. Consequently, numerous miniaturized electrochemical devices modified with different nanomaterials (carbon nanocomposites, metal, and metal oxide nanocomposites) have been developed, and miniaturized electrochemical sensing techniques have been applied in a wide variety of areas. Herein, we review recent research on miniaturized electrochemical sensing techniques for the detection of environmental heavy metal pollutants with the aim of providing an overview of the latest progress and perspectives in this field.