Nitrite (NO2-) is an inorganic contaminant that exists widely in the environment including water and food products, excessive amounts of NO2- would threaten humans and aquatic life. Developing a rapid and convenient sensing method for NO2- remains a great challenge. Herein, a colorimetric and near-infrared fluorescent probe (TBM) was synthesized and applied for sensitively and selectively detecting NO2- in water, food samples and Escherichia coli (E. coli). With the addition of NO2-, the probe TBM solution has a distinct visual color changed from red to colorless and fluorescence intensity at 620 nm quickly decreased. The probe TBM could detect NO2- quantitatively with a detection limit of 85 nM based on a 3σ/slope. Under optimum conditions, TBM has been successfully used to detect NO2- in real-world environmental and dietary samples, with positive results. Besides, paper strips loaded with TBM have been used to visually determine NO2- levels. Most importantly, TBM has also been proven to be able to discriminate from different concentrations of NO2- in E. coli by fluorescence imaging. In summary, the probe TBM was successfully developed for the accurate quantification, naked eyes detection and bioimaging of NO2- in water, food samples and E. coli, which provides a useful tool to better guarantee the quality and safety of daily life and food industry.
Keywords: Colorimetric fluorescent probe; Escherichia coli bioimaging; Near-infrared; Nitrite (NO(2)(−)); Water and food analysis.
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