Visual and quantitative monitoring of thiophenol by a novel deep-red emitting fluorescent probe in environmental and biological systems

Detection of highly toxic thiophenols in biological or environmental systems is of great importance. Therefore, fast, reliable, and sensitive probes are needed to detect thiophenols. Herein, a novel triphenylamine conjugated dicyanoisophorone-based near infrared fluorescence probe is reported to determine trace thiophenol (PhSH) levels. The probe demonstrates a distinct turn-on fluorescence response to thiophenol among the tested ana-lytes and its quantum yield (phi) increases from 0.011 to 0.142. It has low cytotoxicity with cell viability of 90-100% up to 10.0 mu M of the probe, a strong anti-interference capability, a large Stokes shift (150 nm), and a fast response time (<1 min). In addition, the probe exhibits a good linear response to PhSH over the range from 0 to 15.0 mu M with a detection limit of 32.3 nM (R2 = 0.9978). The detection process is also confirmed through HPLC. The practical applicability of the probe is proved by a smartphone platform, TLC kit, plant tissue imaging, soil assay, tap, and lake water analysis with good recovery values (92.3-117%), and concentration-dependent live cell bioimaging PhSH from 5.0 to 15.0 mu M. Therefore, the present probe is a robust candidate for moni-toring PhSH levels in biological and environmental systems.

Automated summary

A novel near infrared fluorescence probe based on triphenylamine conjugated dicyanoisophorone has been reported for the detection of trace thiophenol. The probe exhibits a turn-on fluorescence response to thiophenol, with an increased quantum yield from 0.011 to 0.142. It has low cytotoxicity, strong anti-interference capability, large Stokes shift, fast response time, and good linear response to PhSH. Practical applicability of the probe has been demonstrated in various applications, including smartphone platform, TLC kit, plant tissue imaging, soil assay, and water analysis.