在酸性Tris-盐酸缓冲溶液中，铬天青S与Ca（Ⅱ）和溴化十六烷基三甲基铵反应生成离子缔合物，使瑞利光散射（RLS）信号明显增强并产生瑞利散射新光谱，最大瑞利散射峰位于370 nm，Ca（Ⅱ）的质量浓度在0.003~0.10 mg/L范围内与三元体系的瑞利散射增强程度（ΔI_RLS）呈线性关系，检出限为2.8 ng/mL，定量限为0.42 g/100 g。据此建立了快速、灵敏、准确测定Ca（Ⅱ）的RLS新方法，同时还研究了三元体系的适宜反应条件、反应机理、共存物质的影响及RLS光谱特征。样品的加标回收率为98.14%~102.0%，相对标准偏差RSD（n=6）为1.8%~2.3%，该方法适于市售奶制品中Ca（Ⅱ）的测定。

In an acid Tris-hydrochloric acid buffer solution,chrome azurol S reacts with calcium(Ⅱ) and hexadecyl trimethyl ammonium bromide to form an ion association complex,which leads to a distinctly enhanced Rayleigh light scattering (RLS) signal of system and the appearance of a new Rayleigh light scattering spectrum.The maximum Rayleigh scattering peak is located at 370 nm.The mass concentration of calcium(Ⅱ) in the range of 0.003 to 0.10 mg·L^-1 exhibits linear relationship to the Rayleigh scattering enhanced intensity (ΔI_RLS) of system,with a detection limit of 2.8 ng·L^-1 and a quantitative limit of 0.42 g/100 g.Based on these results,a rapid,sensitive and accurate new Rayleigh light scattering method is established for determining Ca(Ⅱ).The suitable reaction conditions,reaction mechanism,influence of coexisting substances and RLS spectral characteristics for ternary system are discussed.The recoverable rate of samples and RSD(n=6) are in the ranges of 98.14%-102.0% and 1.8%-2.3%,respectively.This method is suitable for the determination of calcium(Ⅱ) in commercial milk products.

庞向东(1962-),男,理学学士,副教授,研究方向为分子光谱分析,cspxdfxsch123456@163.com