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目的:建立一种共振瑞利散射方法测定食品中三聚氰胺的新方法。方法:在pH=5.5的B-R缓冲溶液中,三聚氰胺与巴比妥在四氢呋喃介质中以非共价键结合聚集形成大分子,在λ=296 nm下,激发产生强烈的共振瑞利散射。体系散射强度增强值(ΔI)与三聚氰胺浓度呈现良好的线性关系,据此建立了共振瑞利散射法测定乳制品中三聚氰胺的新方法。结果:在优化的实验条件下,浓度为3.03×10-8mol/L～1.60×10-6mol/L时,体系的共振光散射强度(ΔI)值与三聚氰胺的浓度成线性关系,线性回归方程为ΔI=1594.4c+9.70(c为三聚氰胺的浓度,10-6mol/L),相关系数r=0.9991,检出限为9.1×10-9mol/L。实验对4.0×10-8、8.0×10-8、1.2×10-7mol/L的三聚氰胺标准溶液分别进行11次平行测定,相对标准偏差分别为4.54%、3.31%、4.61%,样品加标回收率为95.0%～97.5%。结论:方法精密度、准确度好,灵敏,操作简便,用于食品中三聚氰胺的测定,结果满意。
Objective: To establish a new resonance resonance Rayleigh scattering method for the determination of melamine in food. Methods: In B-R buffer solution of pH = 5.5, melamine and barbiturate were aggregated to form macromolecules by non-covalent bond in tetrahydrofuran medium, and strong resonance Rayleigh scattering was induced at λ = 296 nm. The linear relationship between the enhancement of scattering intensity (ΔI) and the concentration of melamine showed a good linearity. A new method for the determination of melamine in dairy products by resonance Rayleigh scattering was established. Results: Under the optimized experimental conditions, the concentration of 3.03 × 10-8mol / L ~ 1.60 × 10-6mol / L, the system of the resonance light scattering intensity (ΔI) value and the concentration of melamine linear relationship, the linear regression equation ΔI = 1594.4c + 9.70 (c is the concentration of melamine, 10-6mol / L), the correlation coefficient is 0.9991, the detection limit is 9.1 × 10-9mol / L. In the experiment, the standard solutions of 4.0 × 10-8, 8.0 × 10-8 and 1.2 × 10-7mol / L melamine were determined respectively 11 times in parallel, the relative standard deviations were 4.54%, 3.31% and 4.61%, respectively. The rate was 95.0% ~ 97.5%. Conclusion: The precision, accuracy, sensitivity and simple operation of the method are satisfactory for the determination of melamine in food.