The interference effects in the atomic absorption spectrophotometry determination of chromium and complexing of antimony and tin metal ions and consequent determination in the atomic absorption Spectrophotometry

Abstract

The interferent effects of thirty SlX metal salts vit.h the chromium absorbance in the air-acetylene flame has been studied. Twelve metal interferents of Fe, Co, Ni, Pd, Ti, V, Mg, Al, Zr, W, U and Mo were found to have suppressive interference. The interferents of Zn, Cd, Vm, Pb, Ag, Ce, Cu, Sr, La, Be, Tl, Li, K, Na were found to have enhancing interference. The metals of Ba, Ca, Rh, Y, Pt , Si, .Th, Sb, As, Bi were found to have no effect on chromium absorbance. The interference does not depend on the boiling point of the added foreign metal or particle Slze. The suppreSSlve interference 1S postulated to result from the formation of mixed oxi cle s or bimetallic species. The enhancing interference is postu.Ls.t.etdo resul t from the suppression of chromium a om z.a-: tion. The effect of the alkali sulphates (potassiwu, sodium, lith:'.um,and rubidium sulphates) as releasing agents has been tested ane.results show that they can be used to eliminate botL suppressive and enhancing interferences.

(B) Complexing qf, antimony and tin metal ions and Consequent determination in the atomic absorption Spectrophotometry The atomic absorption spectrophotometric determination of antimony and tin using an aqueous media is hampered by their metal hydrolysis and hence the complexing agents have to be added to their respective solutions to retain the metal ions in aqueous solutions. The atomic absorption spectrophotometric determination of antimony is best achieved ip-presence of either ammonlum fluoride-hydrochloric acid-nitric acid mixture, or in presence of one of the following complexing agents: tartaric acid, citric acid, oxalic acid, and 2-mercaptopropanoic acid. The interference effects of twent;y-nine metals tested is least in ammonium fluoride-hydrochloric acid-nitric acid mixture, comparable in tartaric acid, citric acid and 2-mercaptopropanoic acid. Hovev er , the effect is pr-onounced in oxalic acid. Tin can be successfully determined if any of the above complexing agents or 6M hydrochloric is added. l1