偶氮氯膦Ⅰ光度法同时测定硅砂中氧化钙和氧化镁

Simultaneous Determination of CaO and MgO in Silica-sand by Spectro-photometry with Chloro-phosphonazo Ⅰ

试验了Ca2+、Mg2+与偶氮氯膦Ⅰ同时显色的条件,Ca2+、Mg2+对显色的相互影响。试验结果表明,100μg CaO(50 ml)存在下,不影响MgO的显色,0～50μg MgO(50 ml)符合比耳定律,相关系数r=0.999 8,表观摩尔系数ε=1.83×104 L/mol.cm。30μg MgO(50 ml)存在下,不影响CaO的显色,0～100μg CaO(50 ml)符合比耳定律,相关系数r=0.999 1,表观摩尔系数ε=1.53×104 L/mol.cm。建立了偶氮氯膦Ⅰ光度法同时测定硅砂中CaO、MgO的方法。用所建立的方法对硅砂标准样品进行测定,结果十分满意。

The condition of simultaneous color reaction for Ca^2＋ and Mg^2＋ with chlorophosphonazo I, and the influence of color reaction to each other between Ca^2＋ and Mg^2＋ were investigated. The results show that the presence of 100 μg CaO does not interfere with the color reaction of MgO in 50ml of solution. Beer＇s law is obeyed in the MgO concentration of 0-50 μg/50 ml, and the correlation coefficient r=0.999 8, the apparent molar absorptivity ε MgO =1.83×10^4 L/mol·cm. The presence of 30μ g MgO does not interfere with the color reaction of CaO in 50ml of solution. Beer＇s law is obeyed in the CaO concentration of 0-100 μg/50 ml, and the correlation coefficient r=0.999 1, the apparent molar absorptivity ε CaO =1.53×10^4 L/mol·cm. The method was established for the simultaneous determination of CaO and MgO in silica sand by spectrophotometry with chlorophosphonazo I , and has been applied to analysis of reference samples with satisfactory results.