Negatively charged molybdate mediated nitrogen-doped graphene quantum dots as a fluorescence turn on probe for phosphate ion in aqueous media and living cells.

Author(s) Wang, Y.; Weng, W.; Xu, H.; Luo, Y.; Guo, D.; Li, D.; Li, D.
Journal Anal Chim Acta
Date Published 2019 Nov 08

Since inorganic phosphate ion (PO) plays very important roles in environment or living organisms, developing a selective and sensitive detection method for PO is highly desired. Owing to the superior optical properties, graphene quantum dots (GQDs) have been developed as a promising emitting material in fluorescence analysis. Herein, we reported the first example of negatively charged molybdate-mediated nitrogen doped graphene quantum dots (MoO-mediated N-GQDs) as a fluorescence "off-on" probe for POvia "anion ion-mediated" strategy. The N-GQDs was firstly modified with MoO through a complex bonding system containing ionic and hydrogen bonds. The formation of N-GQDs/MoO complex leaded to photoluminescence (PL) quenching of N-GQDs. In the presence of PO, strong affinity between PO and MoO produced ammonium phosphomolybdate, which destroyed the pre-formed N-GQDs/MoO structure and detached MoO from N-GQDs surface. Thus, the PL of N-GQDS was in turn switched on. Under optimal conditions, this probe exhibited a good linear relationship between PL response and PO concentration in the range from 7.0 to 30.0 μM with a limit of detection of 50 nM. Also this probe with high selectivity and sensitivity has been successfully used to sense PO in natural water, biological fluid, and living cells.

DOI 10.1016/j.aca.2019.07.023
ISSN 1873-4324
Citation Anal Chim Acta. 2019;1080:196205.

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