Cr(Ⅲ)—5-Br-PADAP—Triton X-100析相光度法测定微量铬的研究

STUDY ON THE PHASE SEPARATION SPECTROPHOTOMETRIC DETERMINATION OF TRACE CHROMIUM WITH Cr( Ⅲ )-5-Br-PADAP-Triton X-100 SYSTEM

研究Cr(Ⅲ)-5-Br-PADAP-Triton X-100析相显色体系,建立测定微量铬的析相光度法。在pH 4.5乙酸-乙酸钠介质中,Cr(Ⅲ)、5-Br-PADAP、Triton X-100加热形成的配合物,于95℃恒温浴中析相1h,即被Triton X-100相完全富集,最大吸收峰为593nm,铬含量在0～10μg/5ml服从比耳定律,以硫脲、锰-EDTA、柠檬酸钠、氟化钾为掩蔽剂,测定水样中微量铬,获得满意结果。

The optimun condition of the phase separation colouring reaction of chromium-5-Br-PADAP-Triton X-100 has been studied and a method for the determintion of trace chromium has proposed. In pH 4. 5 HOAc-NaOAc buffer medium, the complex can be eariched in Triton X-100 phase when heating at 95癈 for Ih, in a boiling water bath, the maxium absortion of the complex lies at 593nm. Beer's law is obeyed for chromium concentration in the renge of 0 to 10μg/5ml. The proposed method has been applied to the direct determintion of trace copper in water sample with satisfactory results.