A ratiometric fluorescence-scattered light strategy based on MoS2 quantum dots/CoOOH nanoflakes system for ascorbic acid detection.

A facile ratiometric fluorescence method for ascorbic acid (AA) detection was established by combining the fluorescence of MoS2 quantum dots (QDs) with second-order scattering (SOS) of CoOOH. In MoS2 QDs/CoOOH nanohybrid system, the fluorescence of MoS2 QDs was quenched by CoOOH whereas the intensity of SOS was relatively close to the fluorescence due to the intrinsic high scattering ability of large size CoOOH nanoflakes. With the addition of AA, CoOOH nanoflakes were reduced to Co2+ accompanied the size decline and the disappearance of characteristic absorption in UV-vis spectrum, resulting in the fluorescence recovery and SOS fading. Thus, the ratiometric detection of AA was obtained through the opposite changes of fluorescence and SOS. Under optimized conditions, the detection limit of AA was 0.21 μmol L-1 with a linear range from 0.80 to 32.0 μmol L-1. Furthermore, the MoS2 QDs/CoOOH nanohybrid system was applied to the detection of AA in human serum samples and vitamin C tablets with satisfactory results.