title: Nitrogen- Doped Graphene Quantum Dots: "Turn-off" Fluorescent Probe for Detection of Ag(+) Ions.
abstract: Highly luminescent nitrogen-doped graphene quantum dots (N-GQDs) were prepared from glucose and ammonia as carbon and nitrogen sources, respectively. The N-GQDs showed a strong emission at 458 nm with excitation at 360 nm. The N-GQDs exhibited analytical potential as sensing probes for silver ions determination. Factors affecting the fluorescence sensing of Ag(+) ions such as pH, N-GQDs concentration and incubation time were studied using Box-Behnken experimental design. The optimum conditions were determined as pH 7, N-GQDs concentration 1 mg/mL and time 60 min. It suggested that N-GQDs exhibited high sensitivity and selectivity toward Ag(+). The linear range of N-GQDs and the limit of detection (LOD) were 0.2-40 μM and 168 nM, respectively. The N-GQDs-based Ag(+) ions sensor was successfully applied to the determination of Ag(+) in tap water and real river water samples.
authors.affiliation: Department of Chemistry, Ilam University, Ilam, Iran. rezatabaraki@yahoo.com.
authors.forename: Reza
authors.initials: R
authors.lastname: Tabaraki
authors.affiliation: Department of Chemistry, Ilam University, Ilam, Iran.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Nateghi
keywords: Box–behnken design; Fluorescence; Glucose; Nitrogen-graphene quantum dots; Sensor; Silver