Short communicationValidated quantification method for five ephedrines in dietary supplements using LC-MS/MS: Application to 503 cases

- A novel and simple LC-MS/MS method for simultaneous separation and quantification of five ephedrines in dietary supplements with three different matrices was established.
- Four unique chromatographic columns suitable for analysis of alkaline substances were investigated for separation of five ephedrines.
- Method validation was investigated, especially for matrix effects and expanded uncertainty.
- More than 500 samples were assayed using this method, and data for different matrices to study dietary supplements are presented.

Ephedrines in dietary supplements can arise from herbs or illegal adulteration so a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for separation and quantification of ephedrine, pseudoephedrine, norephedrine, norepseudoephedrine, and methyl-ephedrine, some of which are isomer pairs of pseudo-structures. This method includes liquid-liquid extraction of ephedrines from three typical dietary supplement matrices-solid, liquid, and oil-as well as liquid chromatographic separation. After liquid chromatographic separation, ephedrines are qualitatively and quantitatively analyzed using triple quadrupole mass spectrometry with positive electrospray ionization in multi-reaction monitoring (MRM) mode. Ephedrine recoveries in a solid matrix ranged from 53.3-91.5%, in a liquid matrix from 56.4-102.3%, and in an oil matrix from 51.7-01.2%. Linearity ranges were 10-1000 ng/g in solid and oil matrix and 1-100 ng/ml in liquid matrix. Accuracy was −11.5-16.3%. Intra-day and inter-day variation are less than 5.9% and 7.3%, respectively. Expanded uncertainty of quantification is less than 0.123 ng/g in a solid matrix, less than 0.139 ng/ml in a liquid matrix, and less than 0.158 ng/g in an oil matrix. Data collected for more than 500 routine samples are presented and discussed.