Inductively coupled plasma atomic fluorescence spectrometric determination of cadmium, copper, iron, lead, manganese and zinc

Abstract

An inductively coupled plasma atomic fluorescence spectrometric method is described for the determination of six elements in a variety of geological materials. Sixteen reference materials are analysed by this technique to demonstrate its use in geochemical exploration. Samples are decomposed with nitric, hydrofluoric and hydrochloric acids, and the residue dissolved in hydrochloric acid and diluted to volume. The elements are determined in two groups based on compatibility of instrument operating conditions and consideration of crustal abundance levels. Cadmium, Cu, Pb and Zn are determined as a group in the 50-ml sample solution under one set of instrument conditions with the use of scatter correction. Limitations of the scatter correction technique used with the fluorescence instrument are discussed. Iron and Mn are determined together using another set of instrumental conditions on a 1–50 dilution of the sample solution without the use of scatter correction. The ranges of concentration (µg g^–1) of these elements in the sample that can be determined are: Cd, 0.3–500; Cu, 0.4–500; Fe, 85–250 000; Mn, 45–100 000; Pb, 5–10 000; and Zn, 0.4–300. The precision of the method is usually less than 5% relative standard deviation (RSD) over a wide concentration range and acceptable accuracy is shown by the agreement between values obtained and those recommended for the reference materials.