Visual and ratiometric fluorescent determination of Al3+ by a red-emission carbon dot-quercetin system

The red-emission carbon dots (RCDs) were facile synthesized by the solvothermal method to construct a visual and ratiometric fluorescent probe towards Al 3+ in combined with quercetin (QCT). With the increasing concentration of Al 3+ ( c Al 3+ ), the red fluorescence (605 nm) of the RCDs–QCT system under 360 nm excitation was stable, and meanwhile a green fluorescence (506 nm) appeared and gradually enhanced because of the continuous formation of QCT–Al 3+ complex. The red fluorescence served as the reference signal and the green as the reporter, and then a visual and ratiometric fluorescent probe towards Al 3+ was established based on the variation of the ratio of fluorescence intensities at 506 and 605 nm ( I 506 / I 605 ) and the change of fluorescence color from red to yellow green. On account of the linear relationship between the I 506 /I 605 value and c Al 3+ , the detection range and limit of detection were determined to be 0–35 μM and 90 nM, respectively. The above Al 3+ probe not only exhibited the high selectivity, sensitivity and anti-interface ability, but also realized the quantitative determination of Al 3+ in ultrapure and tap samples with satisfactory results, reflecting its great application potential for practical fluorescent determination of Al 3+ in various aqueous environments.