An Overview on Electrochemical Sensors Based on Nanomaterials for the Determination of Drugs of Abuse.

Drug abuse is considered a serious source of economic and social problems. The identification of drugs of abuse is in demand in forensic and clinical toxicology. There are various methods for the determination of these materials, including chromatographic and mass spectrometric techniques. However, most of these techniques need high-cost equipment, they are time-consuming, and they suffer from complicated sample preparation protocols. In contrast, electrochemical methods are low cost, mobile, and they do not require complicated sample preparation protocols. The use of nanomaterials in electroanalysis has gained significant attention in order to improve selectivity, enhance sensitivity, and lower the limit of detections. Nanomaterials have significantly gained research-interest due to their low cost (due to low amounts of materials being used) and their uniquely size-dependent properties. The incorporation of nanomaterials into host matrices is important to prepare nanocomposite sensor films. Unique properties of nanomaterials and hybrid materials, such as mechanical strength, electrical conductivity, optical responsiveness, specific catalytic and magnetic properties, in addition to high surface area per mass ratio are attractive. Besides providing novel properties, nanomaterials allow low-cost electrode fabrication based on simple technologies. The combination of nanotechnology with modern electroanalytical techniques allows innovation in electrical sensing devices with features like increased mass transport, high sensor surface area, and controlled electrode surface micro-environment. The aim of this review is to give an outline of electroanalytical determination based on nanomaterials focusing on illicit drugs in matrices, such as urine, blood, or saliva. We summarize developments in field-based sensors for determining drugs of abuse.