N-Acetyltaurine – preliminary work to prove its potential as a marker of alcohol consumption

Aims: In both, forensic and clinical settings, highly specific and long-term markers of alcohol consumption are still warranted. Metabolomics in rats following administration of ethanol revealed an increase in urinary excretion of N-acetyltaurine (NAT) with alcohol dose [1]. Methods: NAT has been synthesized using a method similar to that of Johnson et al. [2]. Pyridine and acetic anhydride were added to taurine dissolved in water. The reaction mixture was stirred at 4°C, and left overnight at -20°C. The crude reaction product was cleaned up via a silica gel elution column. Each fraction was checked by LC/MS/MS in negative ionization mode at the following transitions: m/z 166166, 166124, 166107. The internal standard N-propionyltaurine (NPT) was synthesized in the same way substituting acetic anhydride by propionic anhydride; fractions were checked by the following transitions: m/z 180180, 180124, 180107. Subsequently, separation of taurine, NAT and NPT was optimized [3]. Preparation of 100 μL urine aliquots was by dilution and centrifugation. The method was validated and applied to urine specimens obtained from teetotalers and social drinkers. Results and Discussion: Yields of about 30% for both NAT and NPT were in line with that for NAT reported by Johnson et al. [2]. However, the proposed solvent clean up proved insufficient. Run time was 7 min to separate NAT and NPT from taurine being present in authentic urine specimens. Concentrations of NAT in teetotalers significantly differed from those in social drinkers. Conclusion: Both, NAT and NPT can be synthesized in sufficient yield and chromatographic purity following clean up by silica gel. Sample preparation and quantitation by LC/MS/MS using NPT as the internal standard is rapid and promising to be applied to a larger quantity of specimens.