Qualitative and quantitative analysis of ephedrine stimulants in urine by ultra-performance liquid chromatography-tandem mass spectrometry.

RATIONALE Ephedrine analogues are stimulants that are explicitly required to be quantified and characterized in the Anti-Doping Prohibited List of World Anti-Doping Agency. Given the difficulty of diastereoisomers distinguish, this makes the qualitative and quantitative of ephedrine diastereoisomers difficult. METHODS An ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to detect five ephedrine analogues, and two pairs of diastereoisomers were identified by this method. The samples were analyzed qualitatively and quantitatively by a tandem mass spectrometer with an electrospray ionization source (ESI) in the multiple reaction detection mode after one-step dilution. RESULTS The effective detection limits of this method were below 0.5 ng/mL. Matrix effect (range: 83.4% to 102%) was observed in QC samples. The intra- and inter-day precision was lower than 9.16% and 8.60%, respectively, and the accuracy was within ±8.0%. CONCLUSIONS The method is efficient, accurate, stable and sensitive, and fully meets the requirements for the detection of ephedrine substances in stimulants.