A novel yet facile colorimetric and fluorescent dual-channel salamo-type probe for highly effective detection of B4O72− ions in real water samples and its application

•A salamo-type probe NJS was designed and synthesized.•The probe NJS was used to detect B4O72− ions by colorimetric and fluorescence dual-channel.•The probe NJS can detect B4O72− ions in real water samples.•The NJS probe can be mounted on a portable test strip as well as a swab for the actual testing of B4O72− ions. A novel yet facile dual-channel salamo-type fluorescent probe NJS was synthesized successfully in this study. The probe NJS can efficiently detect B4O72− ions through colorimetric and fluorescent dual channels. Under sunlight, when B4O72− ionic solution was added to NJS solution, the mixed solution became a distinct yellow color, in sharp contrast to other anions. The fluorescence detection results showed that fluorescence strength of probe NJS is increased in a short time with the increasement of B4O72− ion content. In addition, the detection limit LOD of probe NJS for B4O72− ions was 2.81 × 10−8 M and the binding constant Ka was 2.20 × 104M−1 by fluorescence titration. According to nuclear magnetic titration and relevant DFT calculations, it was speculated that after adding B4O72− ions into the probe solution, the probe NJS is deprotonated, triggering ICT and FRET effect, resulting in an increase of fluorescence intensity accompanied by redshift, and achieving the specific recognition of B4O72− ions by probe NJS. Finally, the practical application of probe NJS was studied. It was found that the probe can be used for qualitative and quantitative analysis of B4O72− ions through swab, paper test and actual water sample experiments.