Fan Liangfei, Li Weiyi, Jia Dongmin, Zhang Weihua, Ding Yubin
Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
Anal Chem. 2023 Aug 22;95(33):12284-12289. doi: 10.1021/acs.analchem.3c01231. Epub 2023 Aug 9.
The accurate discrimination and quantification of aldehydes is a worthy objective made challenging by their similar chemical reactivities. Considering the nucleophilic reaction mechanism between an aldehyde and a primary amine, it is reasonable to vary the reaction pH to manipulate the reactivity of aldehydes and the stability of the resulting Schiff base for analytical purposes. We have designed and synthesized three benzothiazole-based fluorescent molecules (-) containing an amino group substituted at the ortho-, meta-, and para-positions for aldehyde sensing. It was determined that only having an amino group at the ortho-position exhibits a significant fluorescence response in the presence of formaldehyde at a particular pH, whereas and gave negligible responses, indicating that the ESIPT process in should be responsible for the changes in its fluorescence. Accordingly, a pH-mediated sensor array was constructed by dissolving in aqueous solvents with different pH values. was found to be reliable for the discrimination of seven different aldehydes and identification of unknown aldehyde samples. Moreover, was successfully applied to prepare a fluorescent test paper for the visual detection of formaldehyde vapor.
醛类的准确鉴别和定量是一个有价值的目标，但由于它们相似的化学反应性而具有挑战性。考虑到醛与伯胺之间的亲核反应机理，为了分析目的而改变反应pH以控制醛的反应性和所得席夫碱的稳定性是合理的。我们设计并合成了三种基于苯并噻唑的荧光分子（-），它们在邻位、间位和对位含有取代氨基用于醛传感。已确定只有在邻位具有氨基的分子在特定pH值下甲醛存在时表现出显著的荧光响应，而其他两种分子给出的响应可忽略不计，这表明该分子中的激发态分子内质子转移（ESIPT）过程应是其荧光变化的原因。因此，通过将该分子溶解在不同pH值的水性溶剂中构建了一个pH介导的传感器阵列。发现该阵列对于七种不同醛类的鉴别和未知醛类样品的识别是可靠的。此外，该分子成功应用于制备用于可视化检测甲醛蒸气的荧光试纸。
