Takaharu Kitsuwa

Analysis of natural brassinosteroids by gas chromatography and gas chromatography-mass spectrometry

The microanalysis of various kinds of brassinosteroids as their bismethaneboronate derivatives was investigated by gas chromatography (GC) and gas chromatography—mass spectrometry (GC—MS). GC analysis using a glass capillary column indicated that the brassinosteroid methaneboronates can be detected at the nanogram level. The fragmentation patterns of the bismethaneboronate derivatives of brassinosteroids were examined using GC—EI (electron impact)-MS and GC—CI (chemical ionization)-MS systems. Selected ion monitoring using the GC—CI-MS system was applied to the analysis of natural brassinosteroids in several plants. Brassinolide, castasterone, 28-norbrassinolide, brassinone, 24-ethylbrassinone and dolichosterone were identified in the immature needs and sheaths of chinese cabbage, Brassica campestris L. var. pekinensis, the leaves of green tea, Thea sinensis, the insect galls of the chesnut tree, Castanea crenata L. Sieb. et Zucc., the insect galls and the leaves of Distylium racemosum Sieb. et Zucc. and the whole plant except the roots of the rice, Oryza sativa L. cv. Arborio J1. The results demonstrate that this microanalysis is useful for the screening of brassinosteroids in plants.

Gas chromatographic determination of methylguanidine, guanidine and agmatine as their hexafluoroacetylacetonates

Abstract Seven derivatives each of methylguanidine, guanidine and agmatine have been prepared, and the specificity and volatility of their gas chromatographic detection have been studied. The hexafluoroacetylacetonates have been found to be the most specific for the three guanidines, and are highly sensitive to alkali flame ionization and electron-capture detections. These derivatives are also fairly resistant to hydrolysis occurring in the derivatization process.

Identification of indole-3-acetic acid in Pichia spartinae, an ascosporogenous yeast from Spartina alterniflora marshland environments

(1991). Identification of Indole-3-Acetic Acid in Pichia Spartinae, An Ascosporogenous Yeast from Spartina Alterniflora Marshland Environments. Mycologia: Vol. 83, No. 5, pp. 662-664.