在含有十六烷基三甲基溴化胺(CTMAB)的磷酸盐(PBS)缓冲溶液中,Zn2+对高碘酸钠氧化荧光桃红的反应具有显著的催化效应,催化的结果是导致其荧光强度显著减弱.据此建立了基于Zn2+和银纳米粒子协同双催化效应动力学荧光法测定痕量Zn2+的新方法.实验结果表明:pH7.8的磷酸盐缓冲溶液中,当荧光桃红、NaIO4、银纳米粒子、CTMAB溶液浓度分别为2.0×10-6 mol/L,5.0×10-3g/L,5.0×10-6 mol/L,1.5 × 10-3 g/L时,Zn2+的浓度在5×10-8~100×10-8 g/L范围内与体系的荧光强度改变值呈良好的线性关系,检出限为1.88×10-8g/L.应用于电镀工业废水中Zn2+的检测,测定值与双硫腙光度法基本一致,相对标准偏差(RSD,n=6)≤2.5%.
Zn2+ had significant catalytic effect on the oxidization reaction of phloxine by sodium periodate in phosphate (PBS) buffer solution containing cetyltrimethylammonium bromide (CTMAB).Then,the fluorescence intensity was reduced remarkably.According to this principle,a new determination method of trace Zn2+ by dual catalytic kinetic fluorimetry was established based on the synergy effect of Zn2+ and silver nanoparticle.The results showed that,when the concentration of periodate,NaIO4,silver nanoparticle and CTMAB in PBS buffer solution (pH 7.8) was 2.0× 10-6 mol/L,5.0 × 10-3 g/L,5.0× 10-6 mol/L and 1.5× 10-3 g/L,respectively,the concentration of Zn2+in the range of 5× 10-8-100 × 10-8 g/L showed good linearity to the change of fluorescence intensity of system.The detection limit was 1.88 × 10-8 g/L.The proposed method was applied to the determination of Zn2+ in electroplating industrial wastewater.The found results were consistent with those obtained by dithizone photometric method.The relative standard deviation (RSD) was less than 2.5 %.