Determination of trace amounts of boron by microwave plasma torch atomic emission spectrometry using an on-line separation and preconcentration technique

Abstract

A new system for the determination of trace amounts of boron by flow injection microwave plasma torch atomic emission spectrometry is proposed. In the system, a strongly acidic cation-exchange column is connected in series with a strongly basic anion-exchange column. By the combined function of the two columns, interferences (e.g., iron) in the sample solution are removed and the analytical performance improved. Optimization studies illustrate the dependence of the analytical signals of boron on various parameters, including observation height, microwave forward power, flow rates and acidities of the sample solution and the eluents in both columns. The effect of concomitant ions on the relative emission intensity of boron is also examined. Detection limits of 0.0055 mg l^–1 at 45 samples h^–1 and 0.0018 mg l^–1 at 20 samples h^–1 with a precision of 4.2% at the 0.020 mg l^–1 level of boron were achieved. With sample columns of 1.25 and 5.0 ml, enrichment factors of 22 and 88 were obtained, respectively. The proposed system has been applied to the determination of trace amounts of boron in steel samples and the results obtained were satisfactory.