Analysis of illicit drugs in human urine by micellar electrokinetic capillary chromatography with on-column fast scanning polychrome absorption detection.

Using micellar electrokinetic capillary chromatography (MECC) with a borate/phosphate buffer containing 75 mM SDS (pH 9.1), common drugs of abuse and/or their metabolites, including opioids, benzoylecgonine, amphetamines, and methaqualone, can easily be analyzed. After solid-phase extraction of 5 mL of urine, drug concentrations down to about 100 ng/mL can be unambiguously monitored with on-column multiwavelength detection. Peak assignment is achieved through comparison of retention times and absorption spectra of eluting peaks with those of computer-stored model runs. The effectiveness of the approach is demonstrated with data obtained from different patient urines which tested positively for one or several drugs using nonisotopic immunoassays. Results suggest that MECC of illicit drugs is a highly specific and sensitive instrumental approach suitable for confirmation testing following a positive response of a toxicological screening procedure.