Determination of Chromium in Soil and Sea-sediment by Atomic Absorption Spectrophotometry

Abstract

With an aim of its application to the analysis of chromium in soil and sea-sediment, the interference of diverse ions on the absorbance of chromium and its elimination with air-acetylene flame was investigated.
Chromium in the sample was eluviated by decomposing it with hydrochloric acid prior to the atomic absorption spectrophotometric procedure.
The condition recommended for chromium determination were as follows, wavelength; 357.9 nm, air pressure; 1.5 kg/cm² (flow rate; 7.1 l/min), acetylene pressure; O.28 kg/cm² (flow rate; 1.4 //min), beam height above burner top; 18 mm.
The depression of chromium absorption was observed in the coexistence of iron, titanium, vanadium, nickel, cobalt, magnesium and barium. The interference of iron, titanium, vanadium, nickel and cobalt could be eliminated by the addition of potassium sulfate to the unknown and standard samples. The interference of magnesium and barium could be eliminated by the addition of aluminum.
Naturally, soil and sea-sediment are rich in interfering elements, such as iron, titanium and vanadium, and contain, much potassium and aluminum. Thus, chromium in soil and seasediment could be determined by directly atomizing the eluviated solution into the air-acetylene flame without being interferred by the presence of several coexisting elements.