甲酚紫高氯酸盐-共振荧光光谱法测定三聚氰胺

Determination of melamine by cresyl violet perchlorate-resonance fluorescence spectrometry

目的:建立一种高灵敏度的共振荧光光谱法测定奶粉中三聚氰胺的新方法。方法:对B-R缓冲溶液-CPC表面活性剂介质中的甲酚紫高氯酸盐进行同步扫描,应用三维荧光和吸收光谱分析同步扫描光谱峰的共振荧光特性;基于三聚氰胺对甲酚紫高氯酸盐的共振荧光强度的抑制作用,建立阻抑共振荧光测定三聚氰胺的分析方法。结果:在9.6×10-8～2.8×10-6mol/L浓度范围内,体系的△F值与三聚氰胺浓度(c,10-6mol/L)之间具有良好的线性关系,线性回归方程为△F=106.59c-5.44,相关系数r=0.9993。检出限为2.87×10-8mol/L。奶粉样品测定的相对标准偏差为1.9%～2.7%,加标回收率为95.0%～103.1%。结论:方法灵敏,操作简便,分析成本低,用于奶粉中三聚氰胺的测定,结果满意。

Objective： To establish a novel method for determination of melamine in milk powder by cresyl violet perchlorate-resonance fluorescence spectra.Methods： After cresyl violet perchlorate solution was scaned,the characteristics resonance fluorescence spectra were analyzed in the B-R buffer solution and surfactant CPC systems by the three dimension fluorescence spectra and absorption spectra.An inhibitory resonance fluorescence method was proposed for the determination of trace melamine,based on the inhibitory effect of melamine on the resonance fluorescence intensity of cresyl violet perchlorate,accordingly.Results： Linear range of the method was 9.6×10-8～2.8×10-6mol/L with r=0.9993.There was a good linear relationship between the resonance fluorescence intensity decreases（△F） and the melamine concentration（c,10-6mol/L）： △F=106.59c-5.44,and the detection limit was 2.87×10-8mol/L（3s/b）.The relative standard deviation（RSD） were 1.9%～2.7% for milk powder（n=6）,sample recoveries were 95.0%～103.1% for milk powder.Conclusion： The proposed method had the advantages of simplicity,high sensitivity,low cost,which had been applied to the determination of melamine in milk powder with satisfactory results.