通过一步法制备了稳定、分散的聚多巴胺包被的银纳米粒子(AgNPs).基于Hg2+与聚多巴胺的吸附作用使AgNPs发生聚集,导致体系吸收信号发生变化,同时溶液颜色也发生相应改变,建立了Hg2+的紫外-可见分光光度法及色度法.线性范围为0.5～5.0μmol/L,检出限为50 nmol/L.表征了紫外-可见光谱、红外光谱及扫描电镜显微成像(SEM),优化了实验条件,并探讨了反应机理.该方法用于实际样品中Hg2+的测定,RSD≤4.4%. Stabilized and dispersed polydopamine-coated silver nanoparticles (AgNPs) were prepared by one-step method, and the aggregation of AgNPs based on the adsorption of Hg2 + and polydopamine resulted in the change of absorption signal of the system and the color of the solution changed accordingly The UV-vis spectrophotometry and colorimetric method of Hg2 + showed that the linear range was 0.5-5.0μmol / L and the detection limit was 50 nmol / L. The UV-Vis, IR and SEM ), The experimental conditions were optimized and the reaction mechanism was discussed.The method was applied to the determination of Hg2 + in real samples with RSD ≤4.4%.