Evaluation of selective detectors for the rapid and sensitive gas chromatographic assay of cytokinins, and application to the analysis of cytokinins in plant extracts.

The performances of four gas chromatographic detectors (nitrogen-phosphorus, flamephotometric, electron-capture and flame-ionisation) were compared for the analysis of permethylated cytokinins. The nitrogen-phosphorus and flame-photometric detectors (selective for nitrogen and sulphur-containing compounds respectively) gave greatly enhanced sensitivity and-or specificity compared with the flame-ionisation detector for a wide range of cytokinin types. The response of the electron-capture and flame-ionisation detectors was quantitatively similar. The improved performance of the nitrogen-phosphorus and flame-photometric detectors was used to develop rapid and simple purification techniques for the assay of zeatin and zeatin riboside in coconut milk; dihydrozeatin and dihydrozeatin riboside in bean leaves and cytokinin nucleosides in wheat-germ transfer RNA.