Simultaneous determination of phenolic acids and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one in wheat (Triticum aestivum L.) by gas chromatography-tandem mass spectrometry.

A procedure using gas chromatography and tandem mass spectrometry (GC-MS-MS) has been developed for the identification and quantification of some allelochemicals in wheat (Triticum aestivum L.). The quantities of allelochemicals in wheat shoots ranged from 2.9 to 110 mg per kilogram of dry shoot residues. Compared with gas chromatography-mass spectrometry (GC-MS), the GC-MS-MS technique significantly increased instrument selectivity and sensitivity, thereby providing more reliable quantitation results in the determination of the phytotoxic compounds examined during this allelopathy research.