A combination of single-drop microextraction and open tubular capillary electrochromatography with carbon nanotubes as stationary phase for the determination of low concentration of illicit drugs in horse urine

► In this study we developed a method for the quantification of important drugs of abuse in racehorses. ► The procedure is a combination of single-drop microextraction and an open tubular capillary electrochromatography using multi-wall carbon nanotubes as a stationary phase. ► The SDME showed to be a powerful tool for extraction/preconcentration of the studied drugs. ► The coating of the capillary allowed the separation of the analytes with high resolution. ► The results obtained show a good capillary efficiencies and an improved of the electrophoretic separation.