SEPARATION AND QUANTIFICATION OF 1,4-BENZOXAZIN-3-ONES AND BENZOXAZOLIN-2-ONES IN MAIZE ROOT EXTRACT BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A high-performance liquid chromatography method is described for the separation and quantification of 1,4-benzoxazin-3-ones and benzoxazolin-2-ones in maize root extract. The four compounds, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3(4H)-one, 2,4-dihydroxy-7,8-dimethoxy-1,4-benzoxazin-3(4H)-one, 2-hydroxy-7-methoxy-1,4-benzoxazin-3(4H)-one and 6-methoxybenzoxazolinone, were separated and identified within 30 min on a C18 reversed-phase column using a gradient of methanol and phosphoric acid. The technique has useful applications in studies of the chemical ecology of plant root and subterranean pest interactions.