Magnetic dispersive solid phase microextraction technique coupled with LC-MS/MS for evaluating content versus label claims in ephedrine-free food supplements

Sport supplements and weight management supplements are prime targets for adulteration. In response to concerns regarding the safety of ephedra-containing food supplements, manufacturers have marketed "ephedra-free" products. Therefore, a rapid and convenient magnetic dispersive solid phase microextraction method is proposed in order to extract ephedrine from complex food supplements. Quantification of ephedrine is accomplished by ion-spray LC-MS/MS using multiple reaction monitoring (MRM) mode. The LC-MS/MS method is validated in the range of 5-100 ng/mg. The proposed procedure is applied to the determination of ephedrine in various food supplements. Sixteen food supplements including sport and weight loss supplements are provided from two local drugstores (Tabriz, Iran). The mean content of the ephedrine, identified in five products, amounted to 1055 ng/mg. The proposed method is reliable and fast for determination of ephedrine content in food supplements.