Determination of 15N enrichment of taurine in cat urine by high resolution fast-atom bombardment mass spectrometry.

A method is described for measuring the stable isotopic enrichment of taurine in cat urine samples by high resolution fast-atom bombardment mass spectrometry, after 15N labelled taurine was given to cats for the purpose of investigating taurine metabolism. The 15N enrichment of taurine was measured after hydrolysis and purification of taurine by anion/cation exchange chromatography. The isotopic ratio of taurine was determined by measuring the M+H]+ ion peaks in the spectra of the unlabelled and labelled compounds under multiple ion scan conditions. The overall standard deviation of the measurement is better than 4%. This method requires no derivation and uses only 500 microL of urine samples.