Spectrophotometric determination of boron in plants after separation as trimethyl borate by microdiffusion

A sensitive and precise method based on microdiffusion is proposed for the determination of traces of boron in plants. A sealed digestion bomb is used; the powdered sample is dissolved in ZnCl₂/AlCl₃ solution containing methanol in the teflon vessel and the trimethyl borate formed is collected in sodium hydroxide pellets. The boron, as an ion-associate of the 2,6-dihydroxybenzoic acid complex and malachite green, is extracted into chlorobenzene. At 629 nm, Beer's law is obeyed for the range 0.05–0.5 μg of boron. The accuracy of the proposed method was confirmed by analyzing the Orchard Leaves and Pepperbush standards.