Abstract: Vitamin C is a small water-soluble molecule in vivo which can be directly involved in the redox reaction, with a variety of physiological activities. Herein, an ultra-bright triple-doped zinc gallogermanate nanostructure with favorable monodispersity and optically stable near infrared (NIR) luminescence whose surface was modified with cobalt oxyhydroxide (CoOOH) was synthesized by a surfactant-aided hydrothermal method in combination with short time calcination, and a nanoprobe for the detection of vitamin C was built based on the specific reaction of CoOOH and vitamin C. The nanoprobe used the ZGGO:Cr3+, Yb3+, Er3+ persistent luminescence nanoparticles (PLNPs) as optical signal units and CoOOH as quencher, allowing the detection of vitamin C with high selectivity and sensitivity based on the inner filter effect (IFE). The results showed that CoOOH could effectively quench the luminescence of PLNPs. Vitamin C could restore the luminescence of PLNPs by reducing CoOOH, which displayed a good linear correlation with the content of vitamin C (R2 = 0.993 15) and a detection limit (LOD) of 1.18 mg/kg. When applied to real samples of lemon, strawberry and kiwi fruit, this method gave results consistent with those from HPLC. In addition, the synthesized ZGGO:Cr3+, Yb3+, Er3+ PLNPs had a long afterglow performance in the near infrared (NIR) region, and therefore could be applied to real-time monitoring and imaging of vitamin C in living cells and organisms without in situ excitation.

Key words: persistent luminescence nanoparticles (PLNPs), nanoprobe, cobalt oxyhydroxide (CoOOH), vitamin C