Analytical method development for the simultaneous quantification of creatine and taurine

Abstract

The consumption of sports supplements containing both creatine and taurine has increased significantly. This rise can be attributed to their synergistic effects on enhancing sports performance and their potential therapeutic benefits. Creatine contributes to muscle contraction and energy metabolism, while taurine is involved in osmoregulation, calcium homeostasis, antioxidant defence, and cardiovascular health. Whether used to supplement physical fitness or for their supposed health benefits, the overall physiological effects of either compound are not fully understood and require further research. To support this, precise and reliable methods are needed to measure creatine and taurine in complex sample matrices. However, simultaneous measurement of both remains challenging. Both lack chromophores, which limits detection using standard HPLC-UV techniques. Furthermore, current analytical methods typically measure them separately, increasing costs, time, and variability. This study aimed to develop and validate analytical techniques for the simultaneous quantitation of creatine and taurine. Two methods were employed: Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS) and quantitative Nuclear Magnetic Resonance spectroscopy (qNMR). An isocratic LC-MS/MS method with a run time of 2.5 minutes was developed using a hydrophilic interaction liquid chromatography column and multiple reaction monitoring transitions on an Agilent Ultivo triple quadrupole mass spectrometer. qNMR was performed on a 600 MHz Bruker Avance NEO spectrometer, with quantification carried out using 3-(trimethylsilyl)propionic acid-d₄sodium salt (TSP) as the internal standard. Both methods were validated according to FDA and ICH guidelines. All validation parameters fell within acceptable limits, demonstrating high accuracy, specificity, and reproducibility. The methods were stress-tested with seven commercially available sports supplements containing creatine, taurine, and other potential interfering substances such as amino acids, whey protein, plant extracts, and minerals. Label claim deviations of +112.21% for creatine and +141.52% for taurine were observed during analysis. These results point to significant inconsistencies in product labelling, reinforcing the need for accurate analytical methods to ensure product quality and consumer safety. Overall, this study developed and validated two analytical techniques for the simultaneous quantitation of creatine and taurine. These methods not only aid in quality control of supplements but also lay a foundation for future research into the physiological and therapeutic applications of these compounds.