RÉSUMÉ
OBJECTIVE@#A rapid color test for screening gamma-hydroxybutyric acid (GHB) and its precursor gamma-butyrolactone(GBL) was investigated in drink and urine samples.@*METHODS@#In an acidic solution, GHB was converted to GBL, which reacted with hydroxylamine hydrochloride in presence of sodium hydroxide, forming hydroxamate. A purple complex was formed when hydroxamate reacted with ferric chloride in acidic condition.@*RESULTS@#Detection limit concentrations of GHB in drinks were between 0.5-2 mg/mL, less than the popular abuse concentrations of GHB. This method was usable for urine, with detection limit concentration 0.5 mg/mL. Interferences of common organic solvents and narcotics and depressants were surveyed.@*CONCLUSION@#This method is simple, safe, and rapid; it facilitates rapid screening of GHB and GBL in clinic and forensic laboratories.