基于CdS@ZnS量子点与罗丹明B能量转移荧光猝灭法检测牛奶中土霉素

Study on Fluorescence Resonance Energy Transfer between CdS@ ZnS QDs and Rhodamine B and Its Application in Determination of Oxytetracycline in Milk

在吐温40存在下的pH 7.6 PBS缓冲溶液中,核壳型量子点CdS@ZnS与染料罗丹明B（RhB）能够发生有效的荧光共振能量转移,使能量给体CdS@ZnS的荧光猝灭,能量受体RhB的荧光增强.当加入土霉素（OTC）后,发现体系中RhB的荧光发生猝灭,且体系荧光猝灭的程度与土霉素浓度在4×10-8～ 60×10-8mol/L范围内呈良好的线性关系,相关系数r为0.999 0,检出限为1.13×10-9 mol/L,以此建立了利用CdS@ZnS-RhB能量转移荧光猝灭法测定土霉素的新方法.方法具有稳定性好、灵敏度高、选择性好等特点,应用于牛奶中土霉素含量的测定,回收率为97.5％～ 103.7％,相对标准偏差（n=6）不大于2.0％.

An effective energy transfer could occur between CdS@ZnS QDs and rhodamine B （RhB）in the presence of Tween 40 in pH 7.6 PBS buffer solution,leading to significant fiurensence qunching of CdS@ZnS QDs（donor） and increase of RhB（acceptor）.As adding oxytetracycline,the fluorescence intensity of FRET system decreased because the electrostatic interaction between RhB and oxytetracycline occurred.A good linear relationship was observed between fluorescence quenched intensities and concentrations of oxytetracycline in the range of 4 × 10-8-60 × 10-8 mol/L,with a correlation coefficient（r） of 0.999 0 and a detection limit of 1.13 × 10-9 mol/L.Based on this,a new determination method for oxytetracycline was developed.With a good stability and high selectivity,the method was applied in the determination of proteins in milk samples with recoveries of 97.5％-103.7％ and relative standard deviations（n =6） not more than 2.0％.