Graphene quantum dots combined with copper(II) ions as a fluorescent probe for turn-on detection of sulfide ions

Abstract

A fluorescent probe for the sensitive and selective determination of sulfide ions is presented. It is based on the use of graphene quantum dots (GQDs) which emit strong and stable blue fluorescence even at high ionic strength. Copper(II) ions cause aggregation of the GQDs and thereby quench fluorescence. The GQDs-Cu(II) aggregates can be dissociated by adding sulfide ions, and this results in fluorescence turn on. The change of fluorescence intensity is proportional to the concentration of sulfide ions. Under optimal conditions, the increase in fluorescence intensity on addition of sulfide ions is linearly related (r 2 =0.9943) to the concentration of sulfide ions in the range from 0.20 to 20 μM, and the limit of detection is 0.10 μM (at 3 σ/s). The fluorescent probe is highly selective for sulfide ions over some potentially interfering ions. The method was successfully applied to the determination of sulfide ions in real water samples and gave recoveries between 103.0 and 113.0 %.

Highly sensitive and selective determination of hydrogen sulfide by resonance light scattering technique based on silver nanoparticles

“…6) A comparison between the analytical characteristics of the proposed method and literature methods for H 2 S determination is summarized in Table 1. It can be seen that our method has a higher sensitivity than electrochemistry [12], ICP-AES [14], CL method [16], and fluorescence method [37]. Its sensitivity is slightly lower than that of the reported HGAFS technique, but the proposed method is more simple than the HGAFS method [38].…”

Nitrogen-doped carbon dots as fluorescence ON–OFF–ON sensor for parallel detection of copper(ii) and mercury(ii) ions in solutions as well as in filter paper-based microfluidic device

“…The limit of detection was calculated using the formula LOD ¼ 3s/k, where s and k were standard deviation of the blank NCDs and slope from the regression equation, respectively. 14,19,30 The detection limit was found to be 6.2 nM and 2.304 nM, respectively, for Hg 2+ and Cu 2+ , which is close to or less than permitted limit of Hg 2+ (6 ppb) and Cu 2+ (2 ppm) ions in drinking water as per the World Health Organization (WHO). 16 Comparison with some of the Hg 2+ or Cu 2+ sensor materials is shown in Table S1.…”

“…Hg 2+ or Cu 2+ ions may bind to NCDs at the -COO À , -OH and/or -NH 2 functional groups, leading to the formation of a non-uorescent metal adduct. 18,20,30 To distinguish between Hg 2+ and Cu 2+ , trisodium citrate was used as a uorescence recovery agent. On addition of 10 mL of 50 mM trisodium citrate, uorescence from the Cu 2+ -NCDs mixture was recovered, while the uorescence from Hg 2+ -NCDs did not recover.…”

Effective Determination of Zn2+, Mn2+, and Cu2+ Simultaneously By Using Dual‐Emissive Carbon Dots as Colorimetric Fluorescent Probe

“…Wang and Zhang invented a fluorescent CD probe for the identification of Mn 2+ based on the quenching of fluorescence of the CDs . Wang and co‐workers also reported a visual detection of Cu 2+ by using hybrid carbon dots; the fluorescence color of the carbon dots changed from pink to blue upon the addition of Cu 2+ , which is easy to observe by the unaided eye, among other examples …”