A trace amount of vanadium was vaporized as 8-hydroxyquinolinate complex by using a low-temperature tungsten boat furnace for sample introduction in ICP-AES. Experimental results suggest that vanadium was vaporized as vanadium(III) 8-hydroxyquinolinate complex. Vanadium(V) and vanadium(IV) were reduced in the heating process before vaporization. The operating conditions were optimized, and the effects of foreign ions were investigated. The existence of tin(II) ion in sample solution was found to enhance the emission intensity of vanadium, improve the precision of the proposed method, and also suppress the interferences from other foreign ions. The detection limit in the presence of 5 μg tin(II) was determined to be 4 pg, and in the absence of tin(II), 7 pg, of vanadium. Sub-μg L-1 levels of vanadium in sample solution could be determined by the proposed method. The precisions in relative standard deviation (% RSD) for 100 pg of vanadium under the same conditions described above were 1.9% and 4.1%, respectively. The contents of vanadium in some standard steel and rock samples determined by the proposed method were in good agreement with their certified values.
Shiquan Tao and Takahiro Kumamaru, "Low-Temperature Electrothermal Vaporization of 8-Hydroxyquinolinate Complex for Determination of Trace Vanadium by ICP-AES," Appl. Spectrosc. 50, 785-789 (1996)