[Quantitative determination of taurine and glycine in the picomole range using [14C]dansyl chloride (author's...

Taurine, a possible neurotransmitter, and the transmitter substance glycine can be determined quantitatively in the picomole range using [14C]dansyl chloride even in the presence of a several thousand fold excess of other amino acids. However, it is necessary to eliminate the excess of dansyl chloride after complete reaction by adding diethylamine. In corresponding microchromatograms on 3 X 3 cm polyamide sheets the dansyltaurine is clearly separated as a circumscript spot without fluorescing contaminations. But commercial [14C]dansyl chloride preparations regularly contain radioactive impurities which do not fluoresce and therefore can only be detected by autoradiography. Since one of these labelled impurities migrates with the usual solvents together with [14C]dansyltaurine during chromatography a method is described for a chromatographic separation of [14C]dansyltaurine from these impurities. As internal standards for preparing calibration curves, alpha-phenylglycine and sarcosine are used. gamma-Aminobutyric acid as well as glutamic acid can react with dansyl chloride to form the corresponding lactams. These lactam rings can be converted with ammonia into the corresponding amides (dansylglutamine and dansyl-gamma-aminobutyramide).