Determination of Glycine Betaine by Pyrolysis-Gas Chromatography in Cereals and Grasses
Glycine betaine content of 22 species of cereals and grasses was determined by pyrolysis-gas liquid chromatography assay.
Betaines as a class were separated from aqueous plant extracts by a three resin ion exchange procedure. Ionic compounds other than betaines were bound on a mixed bed of strong anion and weak cation exchange resins. Betaines pass through the mixed resin and were bound on a strong cation exchange resin, neutral compounds were washed away and the purified betaines eluted with ammonia.
N,N,N-trimethyl betaines purified by the ion exchange procedure were determined by GLC measurement of trimethyl amine resulting from the pyrolysis of the betaine fraction at 350 C. The lower limit of the pyrolysis-GLC assay was about 2 nmole of glycine betaine.
Glycine betaine content of the 22 cereal species tested ranged from 1 to 48 ymole per g dry wt. Glycine betaine content before water stress was a fair predictor of accumulation during a stress period.