【摘要】 提出一种利用纳米铜粒子吸附光度法定量检测微量三聚氰胺含量的方法。以DMF为还原剂,合成了粒径为3nm的纳米铜粒子;将合成所得的纳米铜与三聚氰胺均匀分散在乙二醇溶剂中,配制成不同浓度的三聚氰胺-纳米铜混合液,采用紫外-可见分光光度计检测其吸光度值,建立吸光度-三聚氰胺浓度之间的定量关系,探究纳米铜浓度及反应时间对体系的影响。结果表明:纳米铜对三聚氰胺具有很强的吸附,这种吸附作用通过化学络合作用使其溶解度提高;在UV-Vis吸收光谱中表现为:纳米铜的特征吸收峰位没有发生变化,但吸光度显著下降;其吸附作用时间需18 min以上。在三聚氰胺浓度较小时,吸光度与浓度呈现良好的线性关系,这种线性范围随着纳米铜溶胶的浓度增加而扩大,当纳米铜溶胶浓度为0.005 mol/L时,A-c线性范围为0~1.00 ppm;当纳米铜溶胶浓度为0.008 mol/L时,A-c线性范围扩大到6.00 ppm;经计算,该方法的检出限为0.015 ppm,回收率达到97%~99%,表明这种方法能够准确检测微量三聚氰胺的含量。更多还原

【Abstract】 A new method was firstly proposed to measure trace melamine using copper nanoparticles( Cu NPs) absorption in this paper. 1 ~ 3 nm Cu NPs were prepared with DMF as reducing agent. Cu NPs and melamine were then dispersed in the ethylene glycol solvent and made into a series of different concentrations of melamine-Cu NPs solutions. Their absorbance values were detected by an ultraviolet-visible spectrophotometer. Quantitative relationship between absorbance and concentrations of melamine was established,and the influence of nanometer copper concentration and reaction time on the system was explored. The experimental results illustrate that Cu NPs have a strong absorption to melamine,and it embodies in the significant decrease of the nanocopper characteristic absorption peak intensity with no shift,which indicates that the absorbance decline dose not result from the aggregation of copper nanoparticles. The time for Cu NPs stably absorbing melamine is 18 min or more. There is a good linear relationship between absorbance( A) and melamine concentration( c) when the melamine concentration is small. A-c linear range is 0~ 1.00 ppm for 0.005 mol / L Cu NPs solution,while the A-c linear range extends to 6.00 ppm for 0.008 mol / LCu NPs solution. It indicates that the higher concentration of Cu NPs sol is beneficial to expand the A-c linear range. By the calculation,the method detection limit is 0.015 ppm and the recovery percent is 97% ~ 99%. Therefore,Cu NPs can be used to determine trace melamine quantitatively.更多还原