Examination of emission spectrometric 15N analysis of amino acids and amides separated by thin layer chromatography

The method to determine the abundance of 15N in amino acids and amides, which were separated by thin layer chromatography, was examined. It was found that the previous method, in which silica gel was introduced into the discharge tube, had a serious error in the determination because of the heavy contamination of nitrogen from the silica gel. A simple method was designed in order to avoid this contamination. Silica gel was burned at 5600C for 3 hours and the amino acids and amides were washed away from the silica gel with 50% ethanol. This method decreased the contamination of nitrogen to 1/5 of that present in the previous method. The abundance of 15N in amino acids and amides isolated from plant tissues was determined by this method, and consequently it was made clear that this method was superior to the previous method. (Evans, J.)