Development and validation of a fast LC-MS/MS method for the quantitation of creatine and taurine in sports supplements.

Sports supplements containing a combination of creatine and taurine have seen a dramatic rise in popularity. However, adequate analytical techniques for the quantification of these metabolites in tissue samples and supplements are essential. Liquid chromatography mass spectrometry offers a selective and sensitive alternative but to date, no method has been reported for the quantification of both compounds in combination. The main objective was to develop and validate a fast analytical method using LC-MS/MS and to test its suitability on seven commercial sports supplements. An isocratic method with a run time of 2.5 min using a hydrophilic interaction liquid chromatography column and multiple reaction monitoring transitions was developed and validated for linearity, precision, LOD and LOQ, ruggedness and recovery. Spiking experiments on seven commercial samples were conducted to test for possible ion enhancement/suppression. All validation parameters fell well within acceptable limits and the spiking recoveries of the commercial samples all fell between 81-116%. The seven products revealed large discrepancies between the measured values by as much as +99.66% for creatine and as low as -83.81% for taurine as compared to the label claims. These discrepancies highlight the importance of quality control, as inaccurate labelling could lead to unintentional overdosing, which may cause gastric issues and, in severe cases, kidney problems.