A determination of manganese in plant material by atomic absorption spectroscopy using a methanol-aqueous solvent combination.

Abstract

The effect of various organic solvents upon the absorbance of manganese was investigated. Methanol was found to give the greatest enhancement in sensitivity of the solvents analyzed. The plant material was dry ashed t dissolved in 1.0 N HCl and evaporated to near dryness. The residue was then dissolved in a solution of 1% HCl in methanol. The results obtained were comparable to those obtained using the official AOAC colorimetric methods. The procedure has been used for the analysis of samples containing from 20 to 120 ugm of manganese. A plot of absorbance vs concentration was found to be linear throughout this range and a sensitivity of 30 ugm/ml was obtained. The standards used in atomic absorption spectroscopy work were found to give consistent absorbance reading over a period of 60 days. In contrast standards used for official AOAC colorimetric analysis were found to decrease in intensity within 30 minutes or less.