Li Hongfang, Chen Jie, Huang Baowei, Kong Lingwei, Sun Feifei, Li Lin, Peng Chuanyi, Cai Huimei, Hou Ruyan
State Key Laboratory of Tea Plant Biology and Utilization, College of Tea and Food Science & Technology, Anhui Agricultural University, Hefei 230036, China.
Animal-Derived Food Safety Innovation Team, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, China.
Foods. 2022 Sep 1;11(17):2650. doi: 10.3390/foods11172650.
Rongalite was reported illegally used as a food additive for bleaching purposes and improving the tenderness of foodstuffs, which may endanger public health. At present, rongalite was mostly detected by indirect methods via derivatization or determining its decomposition products. In this study, we developed a new fluorescence sensor for the direct quantification of rongalite based on the principles: (1) dopamine reacts with resorcinol and generates strong fluorophore (azamonardine); (2) rongalite could inhibit the production of fluorophores and then result in lower fluorescence intensity. Hence, the rongalite concentration was inversely proportional to fluorescence intensity of fluorophore. Several crucial reaction conditions of fluorescence sensor were further optimized, such as dopamine and resorcinol concentration, pH values, and reaction time. Under the optimal conditions, the limit of detection of fluorescence sensor was 0.28-0.38 μg/g in vermicelli, wheat and rice powder samples, exhibiting almost 3.5-fold improvement compared to that of lateral flow immunoassay. Moreover, the detection time was substantially decreased to 20 min. The recoveries in spiked samples were 80.7-102.1% with a coefficient of variation of less than 12.6%. In summary, we developed a direct, high throughput, selective and accurate fluorescence sensor that poses a promising application for the rapid detection of rongalite in foodstuffs.
次硫酸氢钠甲醛被报道非法用作食品添加剂以达到漂白目的并改善食品的嫩度，这可能危害公众健康。目前，次硫酸氢钠甲醛大多通过衍生化或测定其分解产物的间接方法来检测。在本研究中，我们基于以下原理开发了一种用于直接定量次硫酸氢钠甲醛的新型荧光传感器：（1）多巴胺与间苯二酚反应生成强荧光团（氮杂莫那定）；（2）次硫酸氢钠甲醛可抑制荧光团的产生，进而导致荧光强度降低。因此，次硫酸氢钠甲醛浓度与荧光团的荧光强度成反比。进一步优化了荧光传感器的几个关键反应条件，如多巴胺和间苯二酚浓度、pH值和反应时间。在最佳条件下，荧光传感器在粉丝、小麦粉和米粉样品中的检测限为0.28 - 0.38 μg/g，与侧向流动免疫分析相比提高了近3.5倍。此外，检测时间大幅缩短至20分钟。加标样品的回收率为80.7 - 102.1%，变异系数小于12.6%。总之，我们开发了一种直接、高通量、选择性和准确的荧光传感器，在食品中次硫酸氢钠甲醛的快速检测方面具有广阔的应用前景。
