Reaction of yttrium with p-nitrochlorophosphonazo and the spectrophotometric determination of yttrium in nickel-base alloys in the presence of cerium sub-group rare earths

Abstract

Yttrium reacts with p-nitrochlorophosphonazo to form a 1 : 3 β-type complex, having an absorption maximum at 731 nm. The complex formation was complete within 10 min in a small volume of 0.2–0.5 M perchloric acid and the resulting complex was stable for at least 4 h after dilution. Under the conditions employed, the molar absorptivity was found to be 8.49 × 10⁴ l mol^–1 cm^–1 at 731 nm. The determination range was 0–6 µg of yttrium in 25 ml of solution and was obtained using a standard addition-deduction method. Using this procedure yttrium can be determined in the presence of a 10-fold amount of lanthanum or cerium without separation. A selective and sensitive procedure for the determination of microamounts of yttrium in nickel alloys is described. The precision and recovery are both satisfactory.