Abstract
An analytical method was established for the determination of trace amounts of refractory metal elements (Ti, V, Zr, Nb, Mo and Ta) in high-purity iron samples by axially viewed inductively coupled plasma atomic emission spectroscopy (ICP-AES). We investigated the analytical method of a trace amount of refractory metal elements in high-purity iron matrix using cupferron coprecipitation separation procedure and by axially viewed ICP-AES with ultrasonic nebulization system and a long torch. The established analytical procedure was as follows. A 1.0 g of high-purity iron sample was decomposed with 150 cm3 of hydrochloric acid (1+4) by heating on a hot plate at 453 K. After cooling the sample solution to room temperature, we added 10 cm3 of ascorbic acid solution and cupferron solution to it, and then separated analyte elements. After filtration, the precipitate and residue were decomposed with 10 cm3 of nitric acid and 10 cm3 of perchloric acid, and evaporated to dryness. After leaving cool, salts were dissolved with nitric acid. The sample solution was determined by axially viewed ICP-AES with ultrasonic nebulization system and a long torch. For the controlled matrix concentration, the good precisions and accuracy were obtained by using matrix-matched standard solutions for calibration curves to the ultrasonic nebulization system method. The limit of determination is considerably low in the ultrasonic nebulization system method, which thus demonstrating the effectiveness of the ultrasonic nebulization system method. The recoveries of added six elements were 100% for Ti, Nb and Mo, and 101% for V and Zr, 102% for Ta; the limits of detection were 0.03 ng cm−3 for Ti and Zr to 1.00 ng cm−3 for Ta.
