论文部分内容阅读
Sumivoshi等人曾在pH3.9用苯萃取18-冠-6络合钾的阳离子(LK~+)与溴甲酚绿的一价阴离子形成的黄色缔合物,在波长410毫微米进行光度测定,但选择性不佳。El-Ghamrv在pH10使四溴萤光素乙酯以一价阴离子状态与铂(Ⅳ)、氨形成红色缔合物——[Pt(NH_3)_6~4+·4(TBFEE~-)]光度测定痕量铂。我们考虑到四溴萤光素(H_2R)应有类似的性质,如能在pH10左右的LiOH-EDTA缓冲液中与LK~+缔合并被苯萃取,则可望[(LK~+)·(HR~-)]呈深红色,不但可在可见光区比色,而且方法对钾的选择性必然会提高。据此我们进行了系统的实验并获得了预期的结果。
Sumivoshi et al. Have used photometric determination of a yellow associate formed by the benzene extraction of a 18-crown-6 complex potassium cation (LK ~ +) with a monovalent anion of bromocresol green at pH 3.9 at a wavelength of 410 nm , But poor selectivity. El-Ghamrv makes tetrabromofluorescein ethyl ester monovalently anionically form a red association with platinum (IV) and ammonia [- (Pt (NH_3) _6 ~ 4 + .4 (TBFEE ~ -)] at pH 10 Determination of trace platinum. We consider that tetrabromofluorescein (H 2 R) should have similar properties. If it can be associated with LK + and be extracted by benzene in LiOH-EDTA buffer at pH 10, it is expected that [(LK ~ +) · HR ~ -]] was dark red, not only in the visible light colorimetric, and the method of selectivity to potassium is bound to increase. Based on this, we conducted systematic experiments and obtained the expected results.