Highly selective detection of phosphate ion based on a single-layered graphene quantum dots-Al strategy.

Determination of phosphate ion (PO) is important in biomedical and environmental arrays because its controlling concentrations are associated with different pathologies or the quality of water. Herein, we report a new type of photoluminescence (PL) probe for highly selective detection of PO based on a single-layered graphene quantum dots chelating with aluminium ions (s-GQDs-Al) system. The PL of s-GQDs can be enhanced by Al through the aggregation-induced emission enhancement (AIEE) effect. With the addition of PO, the PL of the s-GQDs-Al system is faded away because PO has stronger coordination with Al which results in the elimination of AIEE effect and the decrease in the PL intensity of the s-GQDs-Al system. Therefore, the s-GQDs-Al system can behave as an on-off type PL probe for PO detection. It is found that the PL intensity ratio (I/I) of s-GQDs in the presence of Al at 463nm is proportional to the concentration of PO in the range of 0.25-7.5μM with the limit of detection as low as 0.1μM. This selective assay has a great application prospect in the complex matrixes owing to its simplicity and specificity for PO detection.