Semi-quantitative analysis of drugs of abuse, including tetrahydrocannabinol in hair using aqueous extraction and immunoassay

A semi-quantitative analytical screening procedure for the determination of cocaine, amphetamines, opiates, and delta-9-tetrahydrocannabinol in hair has been developed. The procedure employs an aqueous extraction buffer, uses only 10mg of hair, requires 2h of incubation for the extraction to occur, and multiple drug classes can be screened using enzyme linked immunosorbent assays. Hair calibration standards were prepared around the recommended cut-off concentrations of the Society of Hair Testing. All drug classes showed excellent linearity over the concentration range tested, indicating that immunochemical screening can be used in a semi-quantitative mode for hair analysis using an aqueous buffer, rapid extraction and a small amount of hair.