The exquisite integration of 1,3,4-thiadiazole and large conjugated group for constructing multi-functional fluorescence probe to detect TNP and Cu2+ in environment, food and living cells.

2,4,6-Trinitrophenol (TNP) and copper ion (Cu2+), as widely used industrial materials, poses potential threat to ecological environment and food safety. Thus, 2-(2-hydroxyphenyl)-1,3,4-thiadiazole was utilized as bi-functional skeleton and three fluorescent probes XL, XD and XS for dual detection of TNP and Cu2+ were synthesized. The influence of introducing carbazole, triphenylamine and tetraphenylethylene as chromophore and auxiliary on their fluorescence properties, recognition performance and detection mechanism was explored by systematically experimental study and DFT calculations. Ideally, XL showed the best potentiality as multifunctional fluorescence probe with a rapid response and high sensitivity (LODs of 0.16 μM for TNP and 0.26 μM for Cu2+). More importantly, many methods including UV-vis spectral responses, pH control, EDTA masking agent and differences in response kinetics could be used to separate TNP and Cu2+. Furthermore, it was successfully applied to the detection in water, soil, plant foods and alcoholic drinks, supported on-site visual analysis via test strips and smartphones, and was applicable to Cu2+ imaging in living cells. This strategy provided a technical pathway for rapid screening and field analysis of both TNP and Cu2+ in real samples.