建立了快速测定皮蛋中Cd的双波长共振瑞利散射法.在pH 5.72的Tris-盐酸缓冲介质中,Cd(Ⅱ)与固绿FCF-溴代十六烷基吡啶结合生成三元络合物,导致体系的双波长共振瑞利散射(DWO-RRS)光谱显著增强,最大和次大共振瑞利散射峰分别位于367 nm和469 nm波长处,在此二波长处,Cd(Ⅱ)的质量浓度在0.004～0.22 mg/L内与体系的共振瑞利散射(RRS)增强程度△IRRS呈线性关系,检出限(3σ/S)为1.3 ng/mL,定量限为0.012 mg/kg.文中还研究了反应条件和共存物质的影响,反应机理及RRS增强的原因.结果表明,方法有较高的灵敏度和良好的选择性,据此,提出了简便、快速、灵敏、准确测定痕量Cd(Ⅱ)的双波长光散射新方法,用于皮蛋中Cd的测定,回收率为97.8％～102％,相对标准偏差(RSD)(n=5)为2.1％ ～2.6％.%A new and fast dual-wavelength overlapping resonance Rayleigh scattering(DWO-RRS) method was developed to detect cadmium in preserved eggs.In a Tris-hydrochloric acid buffer medium at pH 5.72,cadmium (lⅡ) can be bound with fast green FCF-hexadecylpyridinium bromide to form a ternary complex.As a result,the new spectra of DWO-RRS appeared and its intensities was enhanced greatly.The largest and the second largest resonance Rayleigh scattering peak were located at 367 nm and 469 nm respectively.Under these two wavelengths,resonance Rayleigh scattering (RRS) intensity (△IRRs) was directly proportional to the cadmium (Ⅱ) mass concentration in a range of 0.004-0.22 mg/L.The methods had high sensitivity with the detection limit (3σ/S) of 1.3 ng/mL and quantitation limit of 0.012 mg/kg.The optimal conditions and the effects of coexistent substances of RRS method were investigated.In addition,the reasons for RRS enhancement and reaction mechanism of ternary complex were discussed.Results indicated that this assay had a high sensitivity and good selectivity.This simple,rapid,highly sensitive,accurate and new dual-wavelength scattering method had been proposed to determine trace cadmium (Ⅱ).The method was applied to determine the content of cadmium in a series of preserved eggs,the values of recovery and relative standard deviation (RSD) (n =5) were found in the ranges of 97.8％-102％ and 2.1％-2.6％ respectively.
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