College of Environment and Resource , Shanxi University , Taiyuan 030006 , P. R. China.
Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province , Taiyuan 030031 , P. R. China.
J Agric Food Chem. 2019 Aug 7;67(31):8452-8458. doi: 10.1021/acs.jafc.9b02326. Epub 2019 Jul 24.
Insights into the environmental fates of nitrated polycyclic aromatic hydrocarbons (NPAHs) in edible vegetables are of great significance for better evaluating human exposure to NPAHs through the dietary pathway. In this work, a fluorescence quenching method using graphene quantum dots as a fluorescent probe was first applied for the in vivo determination of 9-nitroanthracene (9-NAnt) and 1-nitropyrene (1-NPyr) adsorbed on the leaf surfaces of living lettuce ( L.) seedlings. Moreover, the photolysis kinetics and mechanisms of the two adsorbed NPAHs were discussed. The photodegradation kinetics followed the pseudo-first-order equation, and the photodegradation half-life of 1-NPyr (7.4 ± 0.2 h) was greater than that of 9-NAnt (2.3 ± 0.1 h). Anthraquinone and pyrenediones were identified to be the main photolytic products of 9-NAnt and 1-NPyr, respectively. Intramolecular rearrangement was the most reasonable mechanism for the NPAH photolysis. The photolysis-driven degradation exhibited a key role in scavenging NPAHs from the vegetable leaf, indicating the reduction of NPAH transportation in the food chain.
深入了解食用蔬菜中硝多环芳烃（NPAHs）的环境归宿，对于通过饮食途径更好地评估人类接触 NPAHs 的情况具有重要意义。在这项工作中，首次应用基于石墨烯量子点的荧光猝灭法，对活体生菜（L.）幼苗叶片表面吸附的 9-硝基蒽（9-NAnt）和 1-硝基芘（1-NPyr）进行了体内测定。此外，还讨论了两种吸附 NPAHs 的光解动力学和机制。光降解动力学遵循准一级方程，1-NPyr（7.4 ± 0.2 h）的光降解半衰期大于 9-NAnt（2.3 ± 0.1 h）。蒽醌和芘二酮分别被鉴定为 9-NAnt 和 1-NPyr 的主要光解产物。分子内重排是 NPAH 光解的最合理机制。光解驱动的降解在从蔬菜叶片中清除 NPAHs 方面发挥了关键作用，表明减少了 NPAH 在食物链中的运输。
