QUANTIFICATION OF INTACT CYTOKININ GLUCOSIDES IN DATURA-INNOXIA CROWNGALL TISSUE BY DESORPTION CHEMICAL-IONIZATION MASS-SPECTROMETRY

Cytokinin glucosides are routinely quantified as their aglycones produ ced by enzymic or chemical hydrolysis. ft is, however, important to be able to measure their levels per se. The present paper illustrates th e use of desorption chemical ionisation mass spectrometry coupled with stable Isotope dilution for the determination of intact, underivetize d N- and 0- glucosyl conjugates of cytokinins in Datura innoxia crown gall tissue. A total of six glucosyl conjugates were determined; the t wo N-glucosides, zeatin-7-glucoside and zeatin-9-glucoside, were prese nt in higher quantities than the O-glucosyl derivatives of zeatin, dih ydrozestin and their ribosides.