【摘要】 <正> 二甲苯胺蓝-1(XB-1)作为镁的显色剂,由于试剂本身和它与镁生成的络合物的吸收峰相距太近,所以一直未能受到重视。但自从表面活性剂引入该显色反应后,这一问题才得解决,本文报道溴化十六烷基三甲胺(CTMAB)等表面活性剂对镁与XB-1显色反应的影响。实验表明,在有表面活性剂存在时,XB-1与表面活性剂组成的缔合物其吸收更多还原

【Abstract】 The effect of the color reaction of magnesium ion with xylidyl blue-1 （XB-1） in the presence of cetyltrimethylammonium bromide （CTMAB）, cetylpyridinium bromide （CPB） or Triton X-100 was studied. It was shown that in the presence of either surfactant mentioned the bathochromic shift of the absorption peak of the reagent blank occurs, whereas the absorption peak of the complex formed from magnesium ion with XB-1 is virtually not effected, thus the contrast of the color reaction is increased. It was proved that in the presence of CTMAB magnesium ion formed 1:2 complex with XB-1 and CTMAB formed ion-pair compound with XB-1 simultaneously. Owing to the instability of Ca～, Sr～ and Ba～ XB-1 complexes, they were not formed in the presence of CTMAB、Therefore the interference from Ca²⁺, Sr²⁺ and Ba²⁺ may be eliminated and selectivity of the reaction is improved.The molar ratio of XB-1 to CTMAB in the ion-pair compound was shown to be 1:1 by continuous variation method and the conditional formation constant of the compound was estimated to be 8.5×10⁵ by spectrophotometric method.更多还原