ULTRAVIOLET SPECTROPHOTOMETRIC DETERMINATION OF GADOLINIUM IN CONCENTRATED-SOLUTIONS OF NITRATE SALTS

Ultraviolet spectroscopy was successfully applied for determining the gadolinium concentration in Gd(NO//3)//3 solutions. The **6I//1//5/////2, **6I//1//3/////2 implied by **8S//7/////2 transitions of the Gd**3** plus ion, which are responsible for the fine structure at 272. 8 nm, were selected as a basis for the investigation of three analytical modes, one based on three wavelength measurements (mode ABS) and the others on first- and second-derivative measurements (modes PARTIAL A/ PARTIAL lambda and PARTIAL **2A/ PARTIAL lambda **2). For the particular problem concerned here, namely, to deal with nitrate interference in the spectral region of interest (270-280 nm), the best performance was shown by the first-order derivative mode, which had a precision of plus or minus 0. 035 g L** minus **1, a discrimination limit of 0. 071 g L** minus **1, and an accuracy of 0. 60% for an 8 g L** minus **1 Gd solution.