ZnS:Mn量子点作磷光探针定量检测微量汞

Study of the Mn-Doped ZnS Quantum Dots as the Phosphorescence Probes to Detect the Micro-Quantity Hg^(2+)

以巯基丙酸(MPA)为稳定剂,合成了锰掺杂硫化锌(ZnS:Mn)量子点。由于汞离子对ZnS:Mn量子点的磷光有很强的猝灭作用,应用MPA修饰的ZnS:Mn量子点作磷光探针,定量检测水相中的微量汞离子。相对于荧光,磷光的寿命长、选择性好,没有荧光和散射光的干扰。在优化的实验条件下,当汞离子的浓度在1.0×10^(-5)~1.0×10^(-3)mol·L^(-1)范围内时,ZnS:Mn量子点的△P/P与汞离子浓度之间的关系符合Stem-Volmer方程,其线性相关系数为0.998 8。回收率为85.2%~106.1%,相对标准偏差为3.46%,检出限为9.7×10^(-6)mol·L^(-1)。讨论了量子点磷光的猝灭机理,研究了常见金属离子的干扰作用,选择合适的掩蔽剂,可以有效地消除干扰离子的影响。

In the present paper ,the Mn-doped ZnS quantum dots were synthesized in water ,and the MPA was used as the stabi-lizer .Utilizing the strong quenching effect of Hg2＋ to the phosphorescence of the ZnS ：Mn quantum dots ,the method to detect micro-quantity Hg2＋ in water was established by using the quantum dots as the phosphorescence probes .Compared to the fluo-rescence methods ,the phosphorescence has longer lifetime and higher selectivity ,and avoids the interference of the fluorescence and the scattering light .The result showed that under the optimum conditions ,the relationship between the ΔP/P and Hg2＋concentration was linearity which was ruled by the Stern-Volmer equation while the Hg2＋ concentration was between 1.0 ＆#215; 10-5 and 1.0 ＆#215; 10-3 mol ＆#183; L -1 ,and the linear correlation coefficient was 0.998 8 .The recovery of the method was between 85.2%and 106.1% ,the RSD was 3.46% ,and the detection limit was 9.7 ＆#215; 10-6 mol ＆#183; L -1 .The mechanism of quenching of phospho-rescence was discussed .The interferences of some metal ions could be effectively eliminated by adding appropriate masking agents in the solution .