通过羟基化和氨基硅烷化处理,得到表面接枝氨基的玻片载体.水相合成巯基乙酸修饰的CdTe量子点(CdTe-TGA),采用EDC/NHS活化反应,将量子点偶联到氨基化玻片表面,制备出具有荧光性能的功能化玻片.考察了量子点与EDC的量比、活化时间、偶联温度以及偶联时间对偶联效果的影响.结果表明,在量子点与EDC的量比为1∶30、活化时间1 h、偶联温度30 ℃、偶联时间4 h条件下获得的功能化玻片具有最佳的荧光性能.将该条件下制备的功能化玻片用于水溶液中Pb2+的浓度检测,得到玻片相对荧光猝灭强度随Pb2+浓度变化的线性曲线,线性范围为1.0×10-9~4.0×10-8mol·L-1,检出限为3.8×10-9mol·L-1,且具有良好的选择性.该方法可以灵敏而准确地检测Pb2+浓度.

A new method using wafer modified by CdTe quantum dots to detect the concentration of Pb2+ was discussed in this paper.The surface of glass wafer was modified by means of hydroxylation and aminosilanization to obtain amino-modified slide.The thioglycolic acid-capped CdTe quantum dots synthesized in aqueous phase were successfully coupled on the surface of amino-modified slide by using EDC/NHS activation reaction.Some influence factors were discussed,such as molar ratio of QDs/DEC,activation time,coupling temperature and coupling time.The results show that the functional wafer with QDs/DEC molar ratio of 1∶30,activating time of 1 h,reacting time of 4 h,and reacting temperature of 40 ℃ has the best fluorescence performance.The obtained wafers were successfully used to measure the concentration of Pb2+ in aqueous solution.The quenched fluorescence intensity of functional wafer is linearly proportional to the concentration of Pb2+ between 1.0×10-9 and 4.0×10-8 mol·L-1 with a detection limit of 3.8×10-9 mol·L-1.Good selectivity is also proved by interfering ion experiment.This proposed method can be used to detect Pb2+ sensitively and accurately.