CdSe量子点作探针共振瑞利散射法测定葡聚糖硫酸钠

Resonance Rayleigh Scattering Spectral Method for Determination of Dextran Sulfate Sodium with CdSe QDs as Probe

在乙酸-乙酸钠缓冲溶液中,以巯基乙胺为稳定剂在水相中合成CdSe量子点,巯基乙胺自组装在量子点的表面葡聚糖硫酸钠(Dextran Sulfate Sodium,简称DSS)靠静电引力及疏水作用力结合形成粒径较大的聚集体,这种聚集体的形成导致共振瑞利散射(Resonance Rayleigh Scattering RRS)强度显著增大,最大散射峰位于536 nm.同时二级散射(second-order scattering SOS)和倍频散射(frequency-doubling scattering FDS)的强度也显著增强,最大散射峰分别位于785 nm、290 nm.其中,RRS方法有较高的灵敏度和较低的检出限,它的线性范围为0.012～1.0μg·mL-1,检出限为3.68 ng.mL-1.从而建立用CdSe量子点作为探针RRS法测定葡聚糖硫酸钠的灵敏度高,简便、快速的新方法.应用于尿样的测定结果令人满意.

In the acetic acidsodium acetate buffer solution, cysteamine is employed as stabilizing agents to synthesize CdSe quan- tum dots, cysteamine self-assembled on the surface of CdSe -QDs to form positive supermolec/dar. Dextran Sulfate Sodium （DSS） with univalent positive charges can combine with the CdSe - QDs by the virtue of electrostatic and hydrophoble interaction, forming bigger aggregate. The aggregate arouses resonance Rayleigh Scattering （RRS） intensity enhancing greatly and the maximum wavelengths locates at 536 nm. At the same time, the secondorder scattering （SOS） and frequency -doubling scattering （FDS） intensities are also enhanced and the maximum wavelengths locates at 785 nm and 290 nm respectively. Among them, the RRS method has the higher sensitivity and lower detection limit, its linear range is 0.012 - 1.0 g·mL-l and detection limit is 3.68 ng·mL-1 This simple, fast and sensitive and selective method can be applied to determination of DSS using CdSe - QDs as the RRS probe is developed. Besides the optimum reaction conditions and influencing factors have been discussed. It has been applied to the determination of DSS in synthetic samples with satisfying results.