Determination of strontium in strontium-bearing ferrosilicon by chlorophosphonazo Ⅲ spectrophotometry
ZHONG Guo-xiu,HUANG Qing-hua,GAO lin
(1.Hubei Reserch ＆ Designing Institute of Mechanical Electronic Engineering, Wuhan 430070,China;
2.Hubei Reserch ＆ Designing Institute of Building Material, Wuhan 430071,China；
3.School of Chemistry and Environmental Engineering,Jianghan University,Wuhan 430056,China）
Abstract：The color reaction of chromogenic reagent chlorophosphonazo Ⅲ and strontium was investigated. The experiments showed that in H3PO4 solution at pH 2.9, strontium reacted with chlorophosphonazo Ⅲ to form a blue complex which exhibited an maximum absorption wavelength at 660 nm with apparent molar absorptivity of 2.67×104 L·mol-1·cm-1. Under the optimum experimental conditions, Beer's law was obeyed in the range of 0.04-1.6 mg/L for strontium, and the detection limit was 0.04 μg/mL. After iron was masked by EDTA-Mn solution, this method was used for the determination of strontium in strontium-bearing ferrosilicon samples. The results were in accordance with those obtained by atomic absorption spectrometry, the relative standard deviations (n=5) were 1.5%-2.2%, and the recoveries were 98%-102%.
