Quantification of Intact Cytokinin Glucosides in Datura innoxia Crown Gall Tissue by Desorption Chemical Ionisation Mass Spectrometry

Cytokinin glucosides are routinely quantified as their aglycones produced by enzymic or chemical hydrolysis. It is, however, important to be able to measure their levels per se. The present paper illustrates the use of desorption chemical ionisation mass spectrometry coupled with stable isotope dilution for the determination of intact, underivatized N- and O- glucosyl conjugates of cytokinins in Datura innoxia crown gall tissue. A total of six glucosyl conjugates were determined; the two N-glucosides, zeatin-7-glucoside and zeatin-9-glucoside, were present in higher quantities than the O-glucosyl derivatives of zeatin, dihydrozeatin and their ribosides.