Hu Qinqin, Fu Yingchun, Xu Xiahong, Qiao Zhaohui, Wang Ronghui, Zhang Ying, Li Yanbin
College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, P. R. China.
Analyst. 2016 Feb 7;141(3):1136-43. doi: 10.1039/c5an01989c. Epub 2015 Dec 24.
Acrylamide (AA), a neurotoxin and a potential carcinogen, has been found in various thermally processed foods such as potato chips, biscuits, and coffee. Simple, cost-effective, and sensitive methods for the rapid detection of AA are needed to ensure food safety. Herein, a novel colorimetric method was proposed for the visual detection of AA based on a nucleophile-initiated thiol-ene Michael addition reaction. Gold nanoparticles (AuNPs) were aggregated by glutathione (GSH) because of a ligand-replacement, accompanied by a color change from red to purple. In the presence of AA, after the thiol-ene Michael addition reaction between GSH and AA with the catalysis of a nucleophile, the sulfhydryl group of GSH was consumed by AA, which hindered the subsequent ligand-replacement and the aggregation of AuNPs. Therefore, the concentration of AA could be determined by the visible color change caused by dispersion/aggregation of AuNPs. This new method showed high sensitivity with a linear range from 0.1 μmol L(-1) to 80 μmol L(-1) and a detection limit of 28.6 nmol L(-1), and especially revealed better selectivity than the fluorescence sensing method reported previously. Moreover, this new method was used to detect AA in potato chips with a satisfactory result in comparison with the standard methods based on chromatography, which indicated that the colorimetric method can be expanded for the rapid detection of AA in thermally processed foods.
丙烯酰胺（AA）是一种神经毒素和潜在致癌物，已在薯片、饼干和咖啡等各种热加工食品中被发现。需要简单、经济高效且灵敏的方法来快速检测AA以确保食品安全。在此，基于亲核试剂引发的硫醇-烯迈克尔加成反应，提出了一种用于可视化检测AA的新型比色法。由于配体置换，谷胱甘肽（GSH）使金纳米颗粒（AuNPs）聚集，同时伴随颜色从红色变为紫色。在AA存在的情况下，在亲核试剂催化下GSH与AA发生硫醇-烯迈克尔加成反应后，GSH的巯基被AA消耗，这阻碍了随后的配体置换和AuNPs的聚集。因此，AA的浓度可以通过AuNPs分散/聚集引起的可见颜色变化来确定。这种新方法具有高灵敏度，线性范围为0.1 μmol L⁻¹至80 μmol L⁻¹，检测限为28.6 nmol L⁻¹，并且尤其显示出比先前报道的荧光传感方法更好的选择性。此外，该新方法用于检测薯片中的AA，与基于色谱的标准方法相比结果令人满意，这表明比色法可扩展用于热加工食品中AA的快速检测。
