Heng Chendi, He Bowen, Wang Li
Department of Applied Chemistry, College of Food Science and Biotechnology, Zhejiang Gongshang University, Xiasha University Town, No.18, Xuezheng St, Hangzhou, 310018, China.
J Fluoresc. 2024 Sep;34(5):2157-2167. doi: 10.1007/s10895-023-03432-8. Epub 2023 Sep 15.
In this study, a dual-mode ratiometric fluorometric and colorimetric platform for the determination of nitrite in pickles was proposed by exquisitely employing the fact that non-fluorescent o-Phenylenediamine (OPD) was oxidized by nitrite under acidic conditions to form fluorescent 2,3-diaminophenazine (DAP) (Em = 575), which meanwhile quench the fluorescent nitrogen-doped carbon dots (N-CDs) at 455 nm, the ratio of fluorescence intensity of DAP to N-CDs (F/F) changed with the increase of nitrite accompanied by visible color changes. Thus, nitrite can be quantitatively detected within a wide linear range (10-500 µM) with a low detection limit of 0.45 µM due to the high quantum yield of 39.7% of N-CDs. In addition, the colour of the N-CDs/OPD system changed from transparent to yellow when the nitrite was introduced, enabling colorimetric and on-site visual detection. The detection limit of the colorimetric method was 3.03 µM with a linear range of 10-500 µM. The proposed ratiometric fluorometric method has pleasant selectivity and good immunity to interference.
在本研究中，通过巧妙利用以下事实，提出了一种用于测定泡菜中亚硝酸盐的双模式比率荧光和比色平台：在酸性条件下，非荧光的邻苯二胺（OPD）被亚硝酸盐氧化形成荧光的2,3 - 二氨基吩嗪（DAP）（发射波长Em = 575），同时其会猝灭455 nm处的荧光氮掺杂碳点（N - CDs），随着亚硝酸盐的增加，DAP与N - CDs的荧光强度比（F/F）发生变化，并伴有可见颜色变化。因此，由于N - CDs的量子产率高达39.7%，亚硝酸盐可以在10 - 500 μM的宽线性范围内进行定量检测，检测限低至0.45 μM。此外，当引入亚硝酸盐时，N - CDs/OPD体系的颜色从透明变为黄色，从而实现比色和现场目视检测。比色法的检测限为3.03 μM，线性范围为10 - 500 μM。所提出的比率荧光法具有良好的选择性和抗干扰能力。
