A Fluorescent g-C3N4 Nanosensor for Detection of Dichromate Ions

2020 ◽  
Vol 16 (5) ◽  
pp. 593-601 ◽  
Author(s):  
Ghasem Shiravand ◽  
Alireza Badiei ◽  
Hassan Goldooz ◽  
Mehdi Karimi ◽  
Ghodsi M. Ziarani ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Fluorescence Emission ◽  
High Sensitivity ◽  
Inner Filter Effect ◽  
Quenching Mechanism ◽  
Fluorescence Emission Spectra ◽  
Selective Determination ◽  
Hydrothermal Oxidation ◽  
Highly Sensitive ◽  
Prepared Nanostructures

Background: Dichromate (Cr2O7 2-) ion is one of the carcinogenic and toxic spices in environment which can easily contaminate the environment due to its high solubility in water. Therefore, a lot of attention has been focused on the detection of Cr2O7 2- with high sensitivity and selectivity. Methods: In present work, nitrogen-rich precursor was used for synthesizing graphitic carbon nitride (g-C3N4) nanostructures through hydrothermal oxidation of g-C3N4 nanosheets. The prepared nanostructures show two distinct fluorescence emissions centered at 368 and 450 nm which are highly sensitive toward Cr2O7 2- ions. Results: The as-prepared g-C3N4 was characterized by several techniques such as Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and fluorescence emission spectra. The XRD pattern of prepared nanostructures illustrated two diffraction patterns (at 13.4° and 27.6°) indicating tri-s-tri-azine-based structures. The g-C3N4 exhibited good selectivity and sensitivity toward Cr2O7 2- among other anions. According to titration test, the detection limit and stern-volmer constant (Ksv) were calculated as 40 nM and 0.13×106 M-1, respectively. The investigation of quenching mechanism shows that Cr2O7 2- may form hydrogen bonding with surface groups of g-C3N4 (such as NH2, OH and COOH) resulted in more fluorescence quenching in comparison with the pure inner filter effect. Conclusion: The g-C3N4 nanostructures were successfully synthesized through the hydrothermal oxidation. The as-prepared g-C3N4 can be used as a highly sensitive fluorescent probe for the selective determination of Cr2O7 2 ion among other anions. The quenching mechanism was experimentally studied. According to reliable responses in real sample tests, it can be proposed that g-C3N4 nanostructure is a suitable sensitive nanosensor for detection of Cr2O7 2 ions in aqueous media.

scholarly journals Construction of Two Stable Co(II)-Based Hydrogen-Bonded Organic Frameworks as a Luminescent Probe for Recognition of Fe3+ and Cr2O72− in H2O

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5955
Author(s):  
Qi-Ying Weng ◽  
Ya-Li Zhao ◽  
Jia-Ming Li ◽  
Miao Ouyang
Keyword(s):  
Detection Limit ◽  
Aqueous Media ◽  
Three Dimensional ◽  
Cobalt Atom ◽  
High Sensitivity ◽  
X Ray Diffraction ◽  
Chlorobenzoic Acid ◽  
X Ray ◽  
Highly Sensitive ◽  
Hydrogen Bonded

A pair of cobalt(II)-based hydrogen-bonded organic frameworks (HOFs), [Co(pca)2(bmimb)]n (1) and [Co2(pca)4(bimb)2] (2), where Hpca = p-chlorobenzoic acid, bmimb = 1,3-bis((2-methylimidazol-1-yl)methyl)benzene, and bimb = 1,4-bis(imidazol-1-ylmethyl)benzene were hydrothermally synthesized and characterized through infrared spectroscopy (IR), elemental and thermal analysis (EA), power X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD) analyses. X-ray diffraction structural analysis revealed that 1 has a one-dimensional (1D) infinite chain network through the deprotonated pca− monodentate chelation and with a μ2-bmimb bridge Co(II) atom, and 2 is a binuclear Co(II) complex construction with a pair of symmetry-related pca− and bimb ligands. For both 1 and 2, each cobalt atom has four coordinated twisted tetrahedral configurations with a N2O2 donor set. Then, 1 and 2 are further extended into three-dimensional (3D) or two-dimensional (2D) hydrogen-bonded organic frameworks through C–H···Cl interactions. Topologically, HOFs 1 and 2 can be simplified as a 4-connected qtz topology with a Schläfli symbol {64·82} and a 4-connected sql topology with a Schläfli symbol {44·62}, respectively. The fluorescent sensing application of 1 was investigated; 1 exhibits high sensitivity recognition for Fe3+ (Ksv: 10970 M−1 and detection limit: 19 μM) and Cr2O72− (Ksv: 12960 M−1 and detection limit: 20 μM). This work provides a feasible detection platform of HOFs for highly sensitive discrimination of Fe3+ and Cr2O72− in aqueous media.

Label-Free Fluorescence-Based Aptasensor for the Detection of Sulfadimethoxine in Water and Fish

2019 ◽  
Vol 73 (3) ◽  
pp. 294-303 ◽  
Author(s):  
Xiang-Xiu Chen ◽  
Zheng-Zhong Lin ◽  
Cheng-Yi Hong ◽  
Hui-Ping Zhong ◽  
Qiu-Hong Yao ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
High Sensitivity ◽  
Inner Filter Effect ◽  
Label Free ◽  
Maximum Residue Limit ◽  
Practical Applications ◽  
Specific Recognition ◽  
Ideal Selectivity ◽  
Fish Samples ◽  
Aquaculture Water

Fluorescence-based aptasensors possess high sensitivity but are complicated and usually require multistep labeling and modification in method design, which severely limit the practical applications. Here, a label-free fluorescence-based aptasensor, consisting of aptamer, gold nanoparticles (AuNPs), and cadmium telluride (CdTe) quantum dots (QDs), was developed for the detection of sulfadimethoxine (SDM) in water and fish based on the specific recognition of SDM-aptamer and the inner filter effect of QDs and AuNPs. In the absence of a target, AuNPs dispersed in salt solution because of the aptamer protection, which could effectively quench the fluorescence emission of QDs, while in the presence of SDM, AuNPs aggregated due to the specific recognition of SDM-aptamer to SDM, which resulted in fluorescence recovery. A linear response of SDM concentrations in the range of 10–250 ng mL−1 ( R2 = 0.99) was obtained, and the detection limit was 1.54 ng mL−1 (3σ, n = 9), far below the maximum residue limit (100 ng mL−1) of SDM in edible animal tissues regulated by China and the European Commission. The fluorescence-based aptasensor was applied to the detection of SDM in aquaculture water and fish samples with high accuracy, excellent precision, and ideal selectivity. The results indicated that the developed aptasensor was simple in design, easy to operate, and could be used to detect rapidly and accurately SDM in water and fish samples.

scholarly journals Novel Multifunctional Luminescent Electrospun Fluorescent Nanofiber Chemosensor-Filters and Their Versatile Sensing of pH, Temperature, and Metal Ions

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1259 ◽  
Author(s):  
Bo-Yu Chen ◽  
Yen-Chen Lung ◽  
Chi-Ching Kuo ◽  
Fang-Cheng Liang ◽  
Tien-Liang Tsai ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Color Change ◽  
Ethylenediaminetetraacetic Acid ◽  
Fluorescence Emission ◽  
Volume Ratio ◽  
High Sensitivity ◽  
Electrospinning Process ◽  
Solution Temperature ◽  
Highly Sensitive ◽  
Nanofibrous Membranes

Novel multifunctional fluorescent chemosensors composed of electrospun (ES) nanofibers with high sensitivity toward pH, mercury ions (Hg2+), and temperature were prepared from poly(N-Isopropylacrylamide-co-N-methylolacrylamide-co-rhodamine derivative) (poly(NIPAAm-co-NMA-co-RhBN2AM)) by employing an electrospinning process. NIPAAm and NMA moieties provide hydrophilic and thermo-responsive properties (absorption of Hg2+ in aqueous solutions), and chemical cross-linking sites (stabilization of the fibrous structure in aqueous solutions), respectively. The fluorescent probe, RhBN2AM is highly sensitive toward pH and Hg2+. The synthesis of poly(NIPAAm-co-NMA-co-RhBN2AM) with different compositions was carried on via free-radical polymerization. ES nanofibers prepared from sensory copolymers with a 71.1:28.4:0.5 NIPAAm:NMA:RhBN2AM ratio (P3 ES nanofibers) exhibited significant color change from non-fluorescent to red fluorescence while sensing pH (the λPL, max exhibited a 4.8-fold enhancement) or Hg2+ (at a constant Hg2+ concentration (10−3 M), the λPL, max of P3-fibers exhibited 4.7-fold enhancement), and high reversibility of on/off switchable fluorescence emission at least five times when Hg2+ and ethylenediaminetetraacetic acid (EDTA) were sequentially added. The P3 ES nanofibrous membranes had a higher surface-to-volume ratio to enhance their performance than did the corresponding thin films. In addition, the fluorescence emission of P3 ES nanofibrous membranes exhibited second enhancement above the lower critical solution temperature. Thus, the ES nanofibrous membranes prepared from P3 with on/off switchable capacity and thermo-responsive characteristics can be used as a multifunctional sensory device for specific heavy transition metal (HTM) in aqueous solutions.

scholarly journals Schiff-Based Fluorescent-ON Sensor L Synthesis and Its Application for Selective Determination of Cerium in Aqueous Media

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Maria Sadia ◽  
Jehangir Khan ◽  
Robina Naz ◽  
Muhammad Zahoor ◽  
Ezzat Khan ◽  
...  
Keyword(s):  
Metal Ion ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Aqueous Media ◽  
High Sensitivity ◽  
Transition Metal Ions ◽  
Acetonitrile Solution ◽  
Selective Determination ◽  
Sensitivity And Selectivity

In the present study, a fluorescent sensor L for sensing of Ce3+ ion was designed and characterized by XRD, 1HNMR, and FTIR. Its fluorescence behavior towards metal ion was examined by fluorescence spectroscopy. Chelation-enhanced fluorescence was shown by the sensor L upon interaction with Ce3+ ion. This fluorescent sensor exhibits high sensitivity and selectivity towards Ce3+ ion in acetonitrile solution, forming 2 : 1 (L : M) complex as determined by Job’s plot. Association constant was found to be 1×107 M−1 estimated from the Benesi-Hildebrand plot. No significant interference was observed in the presence of other studied alkali, alkaline, and transition metal ions. A rapid response was observed when employed for the determination of Ce3+ ion in spiked water samples with a limit of detection equal to 3.4×10−8 M.

scholarly journals Highly Luminescent and Biocompatible P and N Co-Doped Passivated Carbon Nanodots for the Sensitive and Selective Determination of Rifampicin Using the Inner Filter Effect

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2275 ◽  
Author(s):  
Baraa Al-Hashimi ◽  
Heshu Sulaiman Rahman ◽  
Khalid Mohammad Omer
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Fluorescence Emission ◽  
Inner Filter Effect ◽  
Single Step ◽  
Carbon Nanodots ◽  
Pharmaceutical Dosage Forms ◽  
Selective Determination ◽  
Filter Effect

The determination of rifampicin in pharmaceutical dosage forms using a rapid, sensitive, selective, biocompatible, and low-cost method is of vital importance in the pharmaceutical analysis field to ensure its concentration is within the effective range when administered. In this study, nitrogen-and-phosphorous-doped carbon nanodots (CNDs) were prepared using a single-step hydrothermal method with ciprofloxacin as the starting material. The CNDs showed a highly intense blue fluorescence emission centered at 450 nm, with a photoluminescence quantum yield of about 51%. Since the absorption of rifampicin was the same as the excitation spectrum of CNDs, inner filter effect (IFE) quenching occurred and it was used as a successful detection platform for the analysis of rifampicin in capsules. The detection platform showed a dynamic linear range from 1 to 100 μM (R2 = 0.9940) and the limit of detection was 0.06 μM (when S/N = 3). The average spike recovery percentage for rifampicin in the capsule samples was 100.53% (n = 5). Moreover, the sub-chronic cytotoxicity of CNDs was evaluated on healthy male mice (Balb/c) drenched with different amounts of CNDs (10 and 50 mg/kg). During this study period, no mortalities or toxicity signs were recorded in any of the experimental subjects. Based on the cytotoxicity experiment, the proposed nano-probe is considered safe and biocompatible.

scholarly journals Novel Multifunctional Luminescent Electrospun Fluorescent Nanofiber Chemosensors-Filter and Their Versatile Sensing of pH, Temperature, and Metal Ions

2018 ◽  
Author(s):  
Bo-Yu Chen ◽  
Yen-Chen Lung ◽  
Chi-Ching Kuo ◽  
Fang-Cheng Liang ◽  
Tien-Liang Tsai ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Color Change ◽  
Ethylenediaminetetraacetic Acid ◽  
Fluorescence Emission ◽  
Volume Ratio ◽  
High Sensitivity ◽  
Electrospinning Process ◽  
Solution Temperature ◽  
Highly Sensitive ◽  
Nanofibrous Membranes

Novel multifunctional fluorescent chemosensors composed of electrospun (ES) nanofibers with high sensitivity toward pH, mercury ions (Hg2+), and temperature were prepared from poly(N-Isopropylacrylamide-co-N-methylolacrylamide-co-rhodamine derivative) (poly(NIPAAm-co-NMA-co-RhBN2AM)) by employing electrospinning process. NIPAAm and NMA moieties provide hydrophilic and thermo-responsive properties (absorption of Hg2+ in aqueous solutions), and chemical cross-linking sites (stabilization of the fibrous structure in aqueous solutions), respectively. The fluorescent probe, RhBN2AM is highly sensitive toward pH and Hg2+. Synthesis of poly(NIPAAm-co-NMA-co-RhBN2AM) with different compositions were carried on via free-radical polymerization. ES nanofibers prepared from sensory copolymers with a 71.1:28.4:0.5 NIPAAm: NMA: RhBN2AM ratio (P3 ES nanofibers) exhibited significant color change from nonfluorescent to red fluorescence while sensing pH or Hg2+, and high reversibility of on/off switchable fluorescence emission when Hg2+ and ethylenediaminetetraacetic acid (EDTA) were sequentially added. The P3 ES nanofibrous membranes had a higher surface-to-volume ratio to enhance their performance than did the corresponding thin films. In addition, the fluorescence emission of P3 ES nanofibrous membranes exhibited second enhancement above the lower critical solution temperature. Thus, the ES nanofibrous membranes prepared from P3 with on/off switchable capacity and thermo-responsive characteristics can be used as multifunctional sensory devise for specific heavy transition metal (HTM) in aqueous solutions.

A Highly Sensitive Fluorescent Sensor for Amitrole Determination in Aqueous Samples

NANO ◽  
2017 ◽  
Vol 12 (07) ◽  
pp. 1750071
Author(s):  
Yue Wang ◽  
Danqun Huo ◽  
Jingzhou Hou ◽  
Junjie Li ◽  
Mei Yang ◽  
...  
Keyword(s):  
Fluorescent Sensor ◽  
Low Cost ◽  
High Sensitivity ◽  
Inner Filter Effect ◽  
Aqueous Samples ◽  
Cdte Qds ◽  
Sensor Platform ◽  
Highly Sensitive ◽  
Wide Range ◽  
Optimized Conditions

A simple yet sensitive fluorescent sensor was reported for amitrole analysis based on integration of gold nanoparticles (AuNPs) and CdTe quantum dots (CdTe QDs) via inner filter effect (IFE). The fluorescence of GSH-coated CdTe QDs can be significantly quenched by AuNPs, and gradually restored in the presence of amitrole. Addition of amitrole induced AuNPs aggregation and decreased their characteristic surface plasmon absorption, which diminished the IFE between them. The sensor platform realized high sensitivity and good reproducibility in low concentration amitrole ranging from 9.5[Formula: see text]nM to 1000[Formula: see text]nM with a detection limit down to 4.75[Formula: see text]nM under the optimized conditions. It also resisted a wide range of interfering counterparts and showed analytical performance comparable to the majority of analytical methods reported in prior studies. We envisioned the first fluorescent amitrole sensor would be potentially useful for low cost on-site amitrole monitoring in real application.

Highly sensitive and selective fluorescent probe for Ag+ based on a Eu3+ post-functionalized metal–organic framework in aqueous media

2014 ◽  
Vol 2 (42) ◽  
pp. 18018-18025 ◽  
Author(s):  
Ji-Na Hao ◽  
Bing Yan
Keyword(s):  
Aqueous Solution ◽  
Metal Organic Framework ◽  
Aqueous Media ◽  
High Sensitivity ◽  
Fast Response ◽  
New Class ◽  
Postsynthetic Modification ◽  
Highly Sensitive ◽  
Metal Organic ◽  
The Eu

A new class of lanthanide luminescent MOFs was generated by postsynthetic modification encapsulating Eu3+ into the pores of MIL-121 (Eu3+@MIL-121). More significantly, the robust Eu3+@MIL-121 shows fast response and high sensitivity to Ag+ ions in aqueous solution, due to a great enhancement in the Eu-luminescence.

Photophysics of High Concentration Systems at a Solution / Solid Interface: An Evanescentwave Study

1996 ◽  
Vol 464 ◽  
Author(s):  
J.A. Elliott ◽  
G. Rumbles ◽  
A.J. De Mello ◽  
H.L. Anderson
Keyword(s):  
Total Internal Reflection ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Inner Filter Effect ◽  
Bulk Solution ◽  
Laser Dye ◽  
High Concentration ◽  
Fluorescence Emission Spectra ◽  
Steady State Fluorescence ◽  
Rhodamine 101

ABSTRACTFor many species the study of photophysical behaviour by fluorescence spectroscopy has been confined to low concentration as a result of the influence of the inner filter effect. In this paper we report how the total internal reflection technique of evanescent wavefluorescence spectroscopy (EWIFS) allows both the collection of distortion free steady-state fluorescence emission spectra and quantitative analysis of such species, in ‘bulk’ solution environment, to significantly higher concentration than can be achieved with a conventional ( right-angle ) geometry. A study of two species, the laser dye rhodamine 101 and anovel meso-substituted zinc prophyrin is presented.

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