Smartphone-integrated ratiometric sensing strategy for on-line quantitation of tetracycline based on functionalized g-C3N4/Eu electrospun film

On-line quantitation of tetracycline (TC) is significant to ensure environmental health and food security. Hence, a novel smartphone-integrated ratiometric sensing platform for on-line quantitative analysis of TC was designed. A CitNa-functionalized g-C3N4/Eu3+ (g-C3N4/CitNa/Eu) composites with blue and red dual-emissive feature were fabricated as dual indicators for shielding background interference, enhancing anti-interference capability. The fluorescent response (F620/F450) ratio and TC concentration demonstrated good linear relationship ranged from 0.0 to 100.0 μM with a detection limit of 1.96 nM. Furthermore, the combination of g-C3N4/CitNa/Eu and polyacrylonitrile polymers forming electrospun film was achieved via electrospinning method. Smartphone-integrated ratiometric sensing platform was developed based on the fluorescent color of electrospun film from blue to light red with TC. This solid sensing platform achieved excellent sensitivity with a detection limit of 7.42 nM. Combining the solid ratiometric fluorescent film with smartphone reader provides a potential way for on-line quantitation of TC in food and other fields.