金纳米粒子荧光增强法测定食用油中PG的研究

Determination of PG in edible oil based on fluorescence enhancing of gold nanoparticles

采用聚乙烯亚胺作保护剂,利用THPC还原氯金酸制备金纳米粒子(AuNPs),该粒子溶液在375nm激发下,在513nm处有荧光发射。实验发现,AuNPs粒子于pH7.8的磷酸盐缓冲介质中加入没食子酸丙酯(PG),体系的激发波长变为333nm,发射波长变为380nm,荧光蓝移且强度明显增强,由此建立了一种快速检测PG的新方法。考察了缓冲体系pH、反应时间、反应温度、AuNPs溶液浓度对PG测定的影响。结果表明,检测PG的最佳条件为:缓冲体系pH7.8,反应时间20min,反应温度25℃,AuNPs原液稀释10倍。在最佳条件下,PG与金纳米体系荧光强度在0.02~1.06μg/mL范围内呈良好的线性关系,相关系数(R^2)为0.9993,检出限为9.7×10^-3μg/mL。该方法用于食用油中PG的检测,加标回收率为92.1%~104.1%。

The gold nanoparticles( Au NPs) were synthesized from chloroauric acid in aqueous solution with polyethyleneimine as protective agent and THPC as reductant. Au NPs showed a fluorescence emission at 513 nm under excitation of 375 nm. It was found that when the Au NPs were added with propyl gallate( PG) in a phosphate buffer medium with pH 7. 8,the excitation wavelength of the system became333 nm,and the intensity wavelength became 380 nm,which caused the gold nano-fluorescence blue shift and the intensity to be significantly enhanced. Thus a new method for determining PG rapidly was established. Different factors were studied,including the AuNPs concentration,buffer solution p H,reaction time and reaction temperature. The results showed that the optimal conditions for determining PG were obtained as follows: buffer solution pH 7. 8,reaction time 20 min,reaction temperature 25 ℃ and AuNPs solution diluted ten times. Under the optimal conditions,the PG mass concentration had a better linear relationship with the AuNPs fluorescence intensity in the range of 0. 02-1. 06 μg/m L. The correlation coefficient( R^2) was 0. 999 3,and the detection limit was 9. 7 × 10^-3μg/m L. The method was used to detect PG in edible oil,and its recovery rate of standard addition was 92. 1%-104. 1%.