Carbon Quantum Dots-Based Fluorescent Hydrogel Hybrid Platform for Sensitive Detection of Iron Ions

Abstract

In this study, we prepared novel fluorescent carbon quantum dots/hydrogel nanocomposite material (CQDsHG) with good adsorption and stable fluorescence detection of Fe3+. The materials were subsequently characterized according to their morphological features, chemical composition, adsorption, and optical properties. The carbon quantum dots (CQDs) were prepared using a microwave-assisted hydrothermal method in no more than 15 min, and the as-prepared CQDs exhibited excellent water solubility, as well as emitted strong bright blue fluorescence with an ultrahigh quantum yield of 93.60%. The CQDs were then loaded into a hydrogel (HG) using the sol-gel method to obtain a functional CQDsHG. The CQDsHG exhibited high adsorption amounts (31.94 mg/g) and a good quenching response for Fe3+, thus, it could be used as a sensor to selectively detect Fe3+ in the linear range of 0–150 μM with a detection limit of 0.24 μM. We observed minimal difference in the fluorescence lifetimes between the CQDsHG with and without a quencher (Fe3+), with values of 5.816 ns and 5.824 ns, respectively, confirming that Fe3+ was statically quenched on CQDsHG. The results indicated that the innovative combination of CQDs and HG can improve the synergistic performance of each component for the adsorption and quantitative detection of heavy metal ions in the aqueous environment.

Strict Twice Iterative Optimization Strategy to Synthesize Ultrabright Fluorescent Carbon Dots for UV and pH Dual-Encryption Fluorescent Ink

“…In addition, quinine sulfate was employed as a standard reference to estimate the relative PLQY of U-CDs. 28 , 29 The details of determination of relative PLQY can be found in the Supporting Information .…”

“…After drying under light, the morphology of U-CDs was observed using a Hitachi H-7650 electron microscope. In addition, quinine sulfate was employed as a standard reference to estimate the relative PLQY of U-CDs. , The details of determination of relative PLQY can be found in the Supporting Information.…”

Rhodamine-Anchored Polyacrylamide Hydrogel for Fluorescent Naked-Eye Sensing of Fe3+

“…The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules28186572/s1, Figure S1 S1: Comparison of the proposed method for Fe 3+ detection with other previously reported fluorescent probes. References [44][45][46][47][48][49] are cited in the Supplementary Materials.…”

“…Fluorescence emission spectra (λ ex = 308 nm) of the sensing system containing 50 μM RBNCH , with 100 μM Fe 3+ for different reaction time; Table S1: Comparison of the proposed method for Fe 3+ detection with other previously reported fluorescent probes. References [ 44 , 45 , 46 , 47 , 48 , 49 ] are cited in the Supplementary Materials.…”

A New Colorimetric Test for Accurate Determination of Plastic Biodegradation

“…Carbon nanodots have widespread applications in bioimaging, owing to properties such as biocompatibility, chemical and photostability and water-dispersibility [ 31 , 32 ]. They have been used in the synthesis of fluorescent hydrogels for different applications [ 33 ] such as sensing and removing rifampicin drug [ 34 ], selectively detecting Fe 3+ [ 35 ] and adsorption and photodegradation of dyes from waste water [ 36 ]. Contrary to these applications aiming to retain a stable hydrogel, a recent study used carbon nanodots in hydrogels to monitor in vivo hydrogel biodegradation [ 19 ].…”