ベリロンIIIを用いた吸着ストリッピングボルタンメトリーによる鉄鋼中微量ほう素の定量

抄録

Adsorptive stripping voltammetry is proposed for the determination of boron at the low μgg^-1 level in iron and steel. Beryllon III was used as a complexing agent for boron(III). Optimum conditions for a complex formation of 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^-5 M Beryllon III; 24 h complexation time. The complex was accumulated on a hanging mercury drop electrode at-0.35 V for 60 s under stirring, and subsequently was cathodically stripped to -0.8 V at a scan rate of 10mVs^-1 by using a differential pulse mode. The interference of iron(III) was eliminated by complexing it with metaphosphoric acid. The cathodic stripping resulted in only a single well-defined peak around -0.5 V. The influence of foreign elements on the determination was evaluated. The calibration graph (peak height vs. boron(III) concentration) in the presence of 1 mg mL^-1 iron(III) was linear over the concentration range of 1-25 ng mL^-1 (correlation coefficient >0.999), with a relative standard deviation (n=4) of 2.6% at 10 ng mL^-1. The minimum limit of determination was 1μgg^-1 of boron in iron and steel. The proposed method could be applied to the determination of trace boron in iron and steel with good precision and accuracy.