USE OF FLOW INJECTION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY FOR THE DETERMINATION OF NIOBIUM, VANADIUM, AND TITANIUM IN MICROALLOYED STEELS

The use of microsampling flow injection inductively coupled plasma-mass spectrometry for the determination of Nh, V, and Ti in microalloyed steels samples is described. A microwave nitric acid digestion procedure, resulting in 0.4% m/v Fe [approximate to 1.75% m/v (NO3)(3)Fe] test solutions, was used for sample dissolution. The flow injection parameters, such as carrier flow rate and sample loop volume, were optimized with respect to sensitivity and stability. Yttrium, with an ionization potential close to that of the analytes considered, and with a close mass number, was used as internal standard. The obtained detection limits, in mu g of analyte per gram of steel, were 0.010 for Nb, 0.017 for Ti, and 0.025 for V. The RSD values, at concentration levels of more than 10 times the detection limit, were less than 1.5%. Three certified reference materials, from the National Institute of Standards and Technology (Gaithersburg, MD)-NIST 2165, 2166, and 2167-were analyzed, from 0.4% m/v steel sample solutions, with 1% v/v HNO3 multielement calibration solutions. The close agreement with the certified values demonstrates the accuracy of the method developed.