SERS的煎炸食品中丙烯酰胺速测方法研究

Rapid and Sensitive Detection of Acrylamide in Fried Food Based on Surface-Enhanced Raman Spectroscopy

丙烯酰胺是一种具有神经毒性、生殖毒性,遗传毒性及免疫毒性的化合物,被列为2A级致癌物。富含碳水化合物的食物经高温烹饪后,丙烯酰胺暴露风险极大,建立对丙烯酰胺的速测方法具有重要的意义和实用价值。表面增强拉曼光谱技术(SERS)近年来发展迅速,利用高SERS活性纳米结构基底可实现对目标物拉曼"指纹"信号的高灵敏增强。复杂基质中目标物的SERS快速分析需要高活性的基底和高效的净化技术。建立了一种基于复合纳米结构的煎炸食品中丙烯酰胺的SERS快速分析方法。利用纳米银阵列负载纳米金粒子(AgNR@AuNPs)作为增强基底,一是该基底基于AgNR纳米棒之间以及AuNPs纳米粒子之间双重"热点"增强作用,对丙烯酰胺具有较高的SERS增强活性;二是该基底中AgNR为固相基底,每次使用前,利用稀硝酸除去表面氧化物,大大提高了SERS分析稳定性。还研究了AuNPs粒径和样品添加顺序对分析灵敏度的影响。煎炸食品中基质干扰严重,结合QuECHERS快速净化技术,在优化除脂、萃取溶剂及净化材料的用量比例、种类的基础上,选择正己烷为除脂溶剂,水∶乙腈(V/V=1∶1)为提取溶剂, MgSO4+NaCl为净化材料, 5 min内完成检测。分析灵敏度1μg·kg-1,在5~100μg·kg-1内以Δν=1 482 cm^-1为定量峰,实现定量分析,线性相关系数r=0.985, 5个添加浓度下回收率为77.1%~93.6%,相对标准偏差小于4.0%。所建立的方法有望用于食品安全现场检测中。

Acrylamide(AAm) is classified as a potential carcinogen and neurotoxin because of its neurotoxicity, reproductive toxicity, genotoxicity and immunotoxicity. The cooking of some carbohydrates-rich food at high temperature increases the high risk for exposure to AAm. It is of great significance and practical value to establish a rapid analytical method for acrylamide. Surface-enhanced Raman scattering(SERS) technique has been developed rapidly in recent years. Based on the highly active SERS substrate, the identification of the fingerprint of compound can be realized. To achieve the rapid SERS analysis of the target substance in the complex substrate, a highly active enhanced substrate and an efficient sample pretreatment technique were required. A rapid, reliable, and quantitative method to determine acrylamide content in fried food based on Ag nanorod/Au nanoparticle composites(AgNR@AuNPs) SERS has been proposed. Based on the enhanced effect of double "hot spots" between AgNR nanorods and AuNPs nanoparticles, the substrate has a high SERS enhanced activity for acrylamide. Besides, AgNR was a solid phase substrate. Before each operation, the oxide on the surface was removed by dilute nitric acid, which greatly improved the stability of SERS analysis. The size of AuNPs and the testing sequence which influence the sensitivity of SERS detection have also been investigated. The fried food was complicated with lots of interferences. The dispersive solid-phase extraction was used for decreasing the serious interference of complex matrix. The defatting and extraction solvent, the kind and ratio of cleanup material have been optimized. The results have shown that the optimized defatting solvent, the extraction solvent and the cleanup materials were hexane, the mixture of water and acetonitrile(1∶1, V/V), and MgSO4+NaClrespectively. The total detection time approximately costed was within 5 min with the limits of detection as low as 1 μg·kg-1 based on the quick pretreatment and SERS enhancement. The peak at Δν=1 482 cm^-1 was selected as the characteristic peak of acrylamide for quantitation in the concentration range of 5~100 μg·kg-1(r=0.985). The recovery rates for acrylamide were 77.1%~93.6% with coefficients of variation less than 4.0% at five different fortified concentrations. The developed method can potentially be used for acrylamide detection in the field.