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文献曾报导了在pH7.5的三(羟甲基)氨基甲烷—硼酸盐的缓冲介质中,用二甲酚橙(XO)—溴化十六烷基吡啶(CPB)测定微量镍,但灵敏度不高。本文研究了在氨性溶液中镍与XO、CPB的显色反应。试验表明:络合物的最大吸收波长在610～614nm处;显色的最佳pH为9.40～10.20;XO用量在0.8～1.6ml(0.1％)之间,CPB用量在0.4～1.2ml(1×10~(-2)M)之间吸光度保持恒定;在显色体系中加入乙二醇二乙醚二胺四乙酸(EGTA)可使空白值降低,测定的重现性提高,加入0.5～2ml(2×10~(-4)M)
It has been reported in the literature that trace nickel is measured with xylenol orange (XO) - cetylpyridinium bromide (CPB) in a tris (hydroxymethyl) aminomethane-borate buffer medium at pH 7.5 Sensitivity is not high. In this paper, the color reaction of nickel with XO and CPB in ammoniacal solution was studied. The results showed that the maximum absorption wavelength of the complex was in the range of 610 ~ 614nm, the optimum pH for color development was 9.40 ~ 10.20, the dosage of XO was between 0.8 ~ 1.6ml (0.1%), the dosage of CPB was 0.4 ~ 1.2ml × 10 ~ (-2) M). The addition of ethylene glycol diethylene glycoldiaminetetraacetic acid (EGTA) to the colorimetric system can reduce the blank value and improve the reproducibility of measurement. Add 0.5 ~ 2ml (2 × 10 ~ (-4) M)