巴比妥共振散射光谱法测定三聚氰胺

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。

Determination of melamine with barbital and resonance reyleigh scattering method

Objective: A novel method was established for the determination of melamine with barbital and resonance rayleigh scattering(RRS).Methods: In the B-R buffer solution(pH=5.5),the melamine reacted with barbital to form large molecules by non-covalently bound in the THF medium.And a strong RRS was generated at the 296 nm.The intensity of scattering value(ΔI) was applied to determination of melamine in dairy products.Results: Under optimal conditions,the ΔI value was linear to the concentration of melamine in the range of 3.03×10-8 mol/L～1.60×10-7mol/L.And the linear regression equation was ΔI=1594.4c+9.70(c was the concentration of melamine,10-6mol/L),correlation coefficient r=0.9991,the detection limit was 9.1×10-9mol/L.When c = 4.0×10-8,8.0×10-8,1.2×10-7 mol/L,the relative standard deviations were 4.54%,3.31%,4.61%(n=11)respectively,the recoveries were 95.0%～97.5%.Conclusion: The method had advantages of good precision and accuracy,high sensitivity and simple operation,which was suitable for the determination of melamine in food.