X-Ray Fluorescence Analysis of Total Iron And Manganese in Soils

Two methods are presented for the quantitative determination of total iron and manganese in soils. The first necessitates the preparation of a calibration curve and is applicable only to soils having similar properties. In this method known increments of Fe2O3 and/or MnO2 are added to the original soil, and X-ray fluorescence intensities are obtained. Analysis of an unknown then utilizes the resulting equation which expresses the relation between intensity and concentration. A second method, here called the two-point method, does not require a calibration curve and is valid for a wider range of samples. A sample is analyzed for either iron or manganese, and X-ray fluorescence intensities are obtained; then a known amount of the element is added to the sample and intensities are again measured. A suitable equation utilizing the two intensities for the determination of the element in the original sample is presented. Data are included to indicate that this method is satisfactory and accurate