Amino Acids (2007) 33: 451–457 DOI 10.1007/s00726-006-0449-0 Printed in The Netherlands Rapid analysis of taurine in energy drinks using amino acid analyzer and Fourier transform infrared (FTIR) spectroscopy as basis for toxicological evaluation S. Triebel, C. Sproll, H. Reusch, R. Godelmann, and D. W. Lachenmeier Chemisches und Veterin€ aruntersuchungsamt (CVUA) Karlsruhe, Karlsruhe, Germany Received August 17, 2006 Accepted September 21, 2006 Published online October 20, 2006; # Springer-Verlag 2006 Summary. So-called energy drinks with very high amounts of taurine (up to 4000 mg=l are usually granted by certificates of exemption) are increasingly offered on the market. To control the currently valid max- imum limits of taurine in energy drinks, a simple and rapid analytical method is required to use it routinely in food monitoring. In this article, we describe a fast and efficient analytical method (FTIR-spectroscopy) that is able to reliably characterize and quantify taurine in energy drinks. The determination of taurine in energy drinks by FTIR was com- pared with amino acid analyzer (ion chromatography with ninhydrin- postcolumn derivatization). During analysis of 80 energy drinks, a median concentration of 3180 mg=l was found in alcohol-free prod- ucts, 314 mg=l in energy drinks with spirits, 151 mg=l in beer-contain- ing drinks and 305 mg=l in beverages with wine. Risk analysis of these products is difficult due to the lack of valid toxicological information about taurine and its interferences with other ingredients of energy drinks (for example caffeine and alcohol). So far, the high taurine con- centrations of energy drinks in comparison to the rest of the diet are scientifically doubtful, as the advertised physiological effects and the value of supplemented taurine are unproven. Keywords: Taurine – Amino acid analyzer – FTIR-Spectroscopy – Energy drinks Introduction Drinks containing ingredients with presumed stimulant properties (so-called energy drinks) are increasingly of- fered on the market. In addition, alcohol containing energy drinks are highly consumed among young adults (BfR, 2003). The market for these drinks has increased in the past years, and, although they might be harmless, overdoses or combination of these with other drinks could be harmful to the health of some consumers in certain circumstances (Santa-Maria et al., 2002). Energy drinks often contain in- gredients such as caffeine, guarana, glucuronolactone and, especially regarded in this study, taurine. Taurine (2-aminoethyl sulphonic acid) is an amino sul- phonic acid naturally present in the diet in foods such as meat, seafood and milk. Taurine is thought to play an ex- tensive role in numerous physiological processes, includ- ing the formation of bile salts, modulation of calcium flux and neuronal excitability (Huxtable, 1992). It was pro- posed to act as an antioxidant, an intracellular osmolyte, a membrane stabilizer, and a neurotransmitter (Brosnan and Brosnan, 2006). A review of the literature shows that taurine may cause physiologically beneficial effects (e.g. like decreased blood pressure in hypertensives) (Ikeda, 1977; Kendler, 1989). However, there is very little research published about the toxicity and synergistic or antagonistic effects of taurine as ingredient of energy drinks, especially in combination with alcohol, to suggest that consumption of taurine is safe to human health (Finnegan, 2003). Therefore, it is neces- sary to control the maximum limits of taurine in food that many European countries have established. To measure the amount of taurine in food, different analytical methods have been developed over the past years. Most of these methods use high-performance liquid chromatography (HPLC) with different detection systems. Taurine as a sulphur amino acid is a compound lacking in a chromophore group. Therefore, the majority of the chro- matographic methods involves pre- or postcolumn-deri- vatization to allow ultraviolet (UV), visible or fluoromet- ric detection (Chaimbault et al., 2004). A few alternative methods use other detection modes, such as electrochemi- cal or refractive index detection (Chaimbault et al., 2004). Recently, planar chromatography with VIS-absorbance