2,3,7-三羟基-9-(2-羟基)萘基荧光酮光度法测定环境样品中微量铬(Ⅵ)

Spectrophotometric Determination of Chromium(Ⅵ) in Environmental Sample with 2,3,7-Trihydroxy-9-(2-hydroxy)naphthyl Fluorone

研究了在阳离子表面活性剂溴化十六烷基三甲胺(CTMAB)存在下,有机显色试剂2,3,7-三羟基-9-(2-羟基)萘基荧光酮(2-HNF)与Cr(Ⅵ)的显色反应和光度性质。结果表明,在pH=7.30的Na2HPO4-KH2PO4缓冲介质中,30min内可反应完全,2-HNF与Cr(Ⅵ)形成摩尔比为2∶1的紫红色络合物,络合物至少能稳定存在12h,其最大吸收波长位于570nm处,表观摩尔吸光系数为1.07×105L·mol-1·cm-1,Cr(Ⅵ)含量在0～1.40μg/5mL范围内符合比耳定律。该分析方法已用于环境样品中微量铬的测定,结果满意。

In the presence of cationic surfactant cetyltrimethylammonium bromide（CTMAB）,the color reaction and photophysical property of 2,3,7-trihydroxy-9-（2-hydroxy）naphthyl fluorone（2-HNF） with chromium（Ⅵ）have been studied.A complex with a chromium（Ⅵ）-to-2-HNF molar ratio of 1∶2is formed in buffer solution（pH=7.30of Na2HPO4-KH2PO4）within 30min.This red complexes is stable for at least 12hours.The maximum absorption wavelength is at 570nm and the apparent molar absorptivity of the complex is 1.07×10^5 L·mol^-1·cm^-1.In the range of 0～1.40μg/5mL,Beer’s law is obeyed.The proposed method has been applied to the determination of the trace chromium in environmental sample with satisfactory results.