title: Fluorescent carbon quantum dot hydrogels for direct determination of silver ions.
abstract: The paper reports for the first time the direct determination of silver ion (Ag(+)) using luminescent Carbon Quantum Dot hydrogels (CQDGs). Carbon Quantum Dots (CQDs) with different superficial moieties (passivate-CQDs with carboxylic groups, thiol-CQDs and amine-CQDs) were used to prepare hybrid gels using a low molecular weight hydrogelator (LMWG). The use of the gels results in considerable fluorescence enhancement and also markedly influences selectivity. The most selective CQDG system for Ag(+) ion detection proved to be those containing carboxylic groups onto their surface. The selectivity towards Ag(+) ions is possibly due to its flexible coordination sphere compared with other metal ions. This fluorescent sensing platform is based on the strong Ag-O interaction which can quench the photoluminescence of passivate-CQDs (p-CQDs) through charge transfer. The limit of detection (LOD) and quantification (LOQ) of the proposed method were 0.55 and 1.83µgmL(-1), respectively, being applied in river water samples.
authors.affiliation: Department of Analytical Chemistry, Marie Curie Building, Campus de Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Cayuela
authors.affiliation: Department of Analytical Chemistry, Marie Curie Building, Campus de Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
authors.forename: M L
authors.initials: ML
authors.lastname: Soriano
authors.affiliation: Department of Chemistry, University of Durham, South Road, DH1 3LE, UK.
authors.forename: S R
authors.initials: SR
authors.lastname: Kennedy
authors.affiliation: Department of Chemistry, University of Durham, South Road, DH1 3LE, UK. Electronic address: qa1vacam@uco.es.
authors.forename: J W
authors.initials: JW
authors.lastname: Steed
authors.affiliation: Department of Analytical Chemistry, Marie Curie Building, Campus de Rabanales, University of Córdoba, E-14071 Córdoba, Spain. Electronic address: qa1vacam@uco.es.
authors.forename: M
authors.initials: M
authors.lastname: Valcárcel
keywords: Carbon Quantum Dots; Fluorescence; Sensor; Silver; Supramolecular gel; Urea