谷胱甘肽修饰的CdTe量子点荧光猝灭法测定化妆品中的铅

Determination of Pb in Cosmetics by Fluorescence Quenching of L-Glutathione Modified CdTe Quantum Dots

以谷胱甘肽(GSH)为稳定剂,在水溶液中制备稳定的CdTe纳米量子点。根据Pb(Ⅱ)对CdTe量子点的荧光具有较强的猝灭效应,建立一种简便灵敏的测定铅的新方法。考察了缓冲液体系、缓冲液pH、量子点的浓度和反应时间等对Pb2+测定的影响。结果表明,在Tris缓冲液(pH8.8)中,CdTe量子点浓度0.0306mmol/L,反应时间5min,体系的相对荧光强度与Pb2+浓度呈良好的线性关系,其线性范围为10—105μg/L,检出限0.27μg/L(3σ),加标回收率在97.6%—101.8%之间。此方法操作简便,快速,可用于化妆品中铅(Ⅱ)含量的测定。

Water-soluble CdTe quantum dots （QDs） were synthesized by means ot L-glutatmone （GSH） as modifying agent in aqueous solution. Based on the fluorescence quenching of CdTe QDs by Pb （ Ⅱ ） ,a convenient and feasible method for the determination of trace Pb （ Ⅱ ） was developed. The effects of experimental conditions including buffer systems,pH of buffer,concentration of CdTe QDs and reaction time on the determination of Pb （ Ⅱ） were investigated. The results showed that,when the concentration of QDs was 0. 0306mmol/L in the Tris buffer at pH 8.8,the reaction time is 5min, the fluorescence quenching degree of the CdTe QDs was linear with Pb （ I ） mass concentration in the range of 10--105μg/L , with correlation coefficient of 0. 9956. The limit of detection （3a） was 0. 27μg/L,the recovery was 97.6 %-101.8 %. This method is fast with simple operation,that can be applied to determining of Pb（ 11 ） content in cosmetics.