溴甲酚绿为内标二苯碳酰二肼光度法测定水体中六价铬的研究

Determination of Chromium(Ⅵ) in the Water with Diphenylcarbazide by Speetrophotometry Using Bromocresol Green as the Internal Standard

采用溴甲酚绿为内标,二苯碳酰二肼(DPC)光度法测定水体中的六价铬。铬与DPC显色铬合物和内标物的最大吸收波长分别为540nm和440nm,校正后的ACr440值与Cr含量之间呈良好的线性关系,相关系数为0.9997。对于高度污染的540/ABr工业废水,可取显色溶液进行任意稀释测定。应用本法对电镀废水进行了测定,其相对标准偏差为1.2%～2.4%,加标回收率为98%～104%。本方法测定结果与标准方法测定结果无显著差异。

A diphenylcarbazide(DPC) photometry with the bromocresol green as the internal standard for the determination of chromium(Ⅵ) in the water has been developed. The maximal absorption wavelength of chromium with the DPC colored complex and internal standard is 540 nm and 440 nm, respectively. A good linear relation between the A^(Cr)_(540)/A^(Br)_(440) and the Cr content with a correlation coefficient of (0.9997) was obtained. For the conalysis of Cr(Ⅵ) in highly polluted industrial waste water, the sample could be diluted by the color development solution in any ratio. This method was applied to the determination of Cr(Ⅵ) in electroplating waste water with the relative standard deviation of 1.2%～2.4% and recovery of 98%～104%.