罗丹明6G·四溴荧光素等色染料离子对浮选光度法测定金

提出了等色染料离子对浮选光度法。向罗丹明６Ｇ（Ｒ６Ｇ）和ＡｕＢｒ－４的甲苯萃取物Ｒ６ＧＡｕＢｒ４中，加入ｐＨ＝５５的（ＮＨ４Ａｃ－ＨＡｃ）缓冲溶液，使Ｒ６Ｇ离子进入水相，并向其中加入与Ｒ６Ｇ颜色相同的四溴荧光素（ＴＢＦ），形成等色染料离子对Ｒ６Ｇ＋·ＴＢＦ－被甲苯浮选。将浮选物溶于丙酮，于５３０ｎｍ处光度测定。由于２个染料分子（Ａｕ∶Ｒ６Ｇ∶ＴＢＦ＝１∶１∶１）同时吸光，方法具有很高的灵敏度，ε＝２０×１０５Ｌ·ｍｏｌ－１·ｃｍ－１；金含量在０～０３６ｍｇ／Ｌ服从比耳定律，相对标准偏差为２９％，方法应用于粗铜中金的测定，结果满意。

Floatation Spectrophotometric Determination of Aurum onIsochromatic Dye Ion Pair with Tetrabromofluorescein and Rhodamine 6G

The floatation spectrophotometric method for determination of aurum with isochromatic dye ion-pair is described. Rhodamine 6G(R6G) was produced and entered into the aqueous phase when pH=55 buffer solution is added to the R6GAuBr4 by isopropyl ether floatation. And then R6G·TBF is floated by tetrabromofluorescein (TBF) with toluene. Dissolve the floatation product in acetone and measure the absorbance of the solution at 530 nm. The sensitivity is raised because of two dyes (Au∶R6G∶TBF=1∶1∶1) assistant effect. The molar absorptivity of this method is 20×105 L·mol-1·cm-1 . Beer′s law holds in the range of 0～036 mg/L with a relative standard deviation of 29%. The method was applied satisfactrily to the determination of aurum in cuprum.