Direct tandem mass spectrometry for the simultaneous assay of opioids, cocaine and metabolites in dried urine spots.

•A dried urine spot (DUS) technique for assessing cocaine and opiates in urine was developed.•The method is adequate for a fast screening and confirmation assay of cocaine/heroin abuse.•Found cocaine, opiates, and metabolites concentrations in urine are similar to those obtained with other conventional methods.