Determination of trace boron in iron and steel by adsorptive stripping voltammetry using beryllon III

Abstract

Adsorptive stripping voltammetry is proposed for determination of boron at low μg g -1 level in iron and steel. Beryllon III was used as a complexing agent for boron(III). Optimum conditions for the formation of the boron(III)-Beryllon III complex were as follows: 0.06 M nitrate-0.04 M sulfate supporting electrolyte at pH 4.5; 1.0×10 -5M Beryllon III; 24 h complexation time. The complex was accumulated on a hanging mercury drop electrode at -0.35 V vs. SCE for 60 s under stirring, and was subsequently cathodically stripped to -0.8 V vs. SCE at a scan rate of 10 mV s -1 using a differential pulse mode. Interference by iron(III) was eliminated by the complexation with metaphosphoric acid. After cathodic stripping, a single well-defined peak was observed at around -0.5V vs. SCE. The influence of foreign elements on the determination was also evaluated. The calibration graph (peak height vs. boron(III) concentration) in the presence of 1 mg mL -1 iron(III) was linear over a concentration range of 1-25 ng mL -1 (correlation coefficient >0.999), with a relative standard deviation (n=4) of 2.6% at 10ngmL -1. The minimum limit of determination was 1 μg g -1 of boron in iron and steel. The proposed method has been proved to be applicable to the determination of trace boron in iron and steel with good precision and accuracy. © 2006 ISIJ.