scholarly journals A Multi-Catalytic Sensing for Hydrogen Peroxide, Glucose, and Organophosphorus Pesticides Based on Carbon Dots

2021 ◽  
Vol 9 ◽  
Author(s):  
Ping Li ◽  
Xiang-Ying Sun ◽  
Jiang-Shan Shen
Keyword(s):  
Catalytic Reaction ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Organophosphorus Pesticides ◽  
Choline Oxidase ◽  
Hydrothermal Route ◽  
One Pot ◽  
Catalytic Systems ◽  
Sensing System ◽  
Fruit Samples

In this work, a facile one-pot hydrothermal route was employed to synthesize a series of fluorescent carbon dots (CDs) by using 20 natural amino acids, respectively, as the starting materials. It was found that the CDs synthesized using phenylalanine could possess the intrinsic peroxidase-like activity that could effectively catalyze a traditional peroxidase substrate like 3, 3’, 5, 5’- tetramethylbenzidine (TMB) in the presence of H2O2 to produce a blue solution; thereby, a catalytic sensing system for H2O2 has been developed. On the basis of this catalytic reaction, together with the fact that glucose oxidase (GOx) can catalyze the hydrolysis of glucose to generate H2O2, a sensitive catalytic sensing system for glucose could be further established. Furthermore, based on this catalytic reaction, taken together with the two enzymatic catalytic systems of acetylcholinesterase (AChE) and choline oxidase (CHO), a highly sensitive multi-catalytic sensing system could be successfully developed for organophosphorus (OPs) pesticides such as dimethoate, DDVP, and parathion-methyl. Limit of detections (LODs) of H2O2 and glucose were estimated to be 6.5 and 0.84 μM, respectively. The limit of detection of the sub-nM level could be obtained for tested dimethoate, DDVP, and parathion-methyl OPs pesticides. The established sensing systems can exhibit good practical application performance in serum and several fruit samples.

scholarly journals Spectrofluorimetric Determination of Hydrochlorothiazide by a Carbon Dots-Based Probe via Inner Filtering Effect and Resonance Rayleigh Scattering

2022 ◽  
Author(s):  
Ali Ghafarloo ◽  
Reza Sabzi ◽  
Naser Samadi ◽  
Hamed Hamishehkar
Keyword(s):  
Carbon Dots ◽  
Rayleigh Scattering ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Emission Spectra ◽  
Cost Effective ◽  
Inner Filter Effect ◽  
Resonance Rayleigh Scattering ◽  
Excitation Spectra ◽  
One Pot

Synthesis of carbon dots (CDs) from natural resources not only enables green synthesis and production of environmentally friendly materials, but also provides a cost-effective probe as a fluorescence nanosensor. The proposed sensor introduces a unique one-pot hydrothermal CDs synthesis from alfalfa leaves, which is promising for sensing hydrochlorothiazide (HCTZ) via inner filter effect (IFE) and resonance Rayleigh scattering (RRS). The as-prepared CDs had wide emission spectra, excitation-dependent emission, high solubility, high stability, and visible fluorescence light with a quantum yield of up to 11%. The absorption of HCTZ overlapped with the excitation spectra of CDs. Therefore, CDs represented excellent quenching due to IFE when HCTZ was gradually added. Furthermore, this fluorescent sensor was successfully used to quantify HCTZ in the linear ranges (0.17-2.50 μg mL-1) with the limit of detection of 0.11 μg mL-1. The sensing system was simple as no surface functionalization was required for CDs, leading to less laborious steps and more cost-effective synthesis. The reaction time was short, i.e., less than 2 min, indicating a simple approach for rapid analysis of HCTZ. By optimizing conditions, successful measurements were carried out on pharmaceutical tablets.

Dual functional carbon dots derived from cornflour via a simple one-pot hydrothermal route

2014 ◽  
Vol 123 ◽  
pp. 107-111 ◽  
Author(s):  
Jumeng Wei ◽  
Xin Zhang ◽  
Yingzhuo Sheng ◽  
Jianmin Shen ◽  
Peng Huang ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Hydrothermal Route ◽  
One Pot ◽  
Dual Functional

Protein as the source for synthesizing fluorescent carbon dots by a one-pot hydrothermal route

RSC Advances ◽  
2012 ◽  
Vol 2 (23) ◽  
pp. 8599 ◽  
Author(s):  
Zhe Zhang ◽  
Jinhui Hao ◽  
Jing Zhang ◽  
Bailin Zhang ◽  
Jilin Tang
Keyword(s):  
Carbon Dots ◽  
Hydrothermal Route ◽  
One Pot ◽  
Fluorescent Carbon Dots ◽  
Fluorescent Carbon

scholarly journals Carbon dots functionalized papers for high-throughput sensing of 4-chloroethcathinone and its analogues in crime sites

2019 ◽  
Vol 6 (9) ◽  
pp. 191017 ◽  
Author(s):  
Yao-Te Yen ◽  
Yu-Syuan Lin ◽  
Ting-Yueh Chen ◽  
San-Chong Chyueh ◽  
Huan-Tsung Chang
Keyword(s):  
Aqueous Solution ◽  
Carbon Dots ◽  
Low Cost ◽  
New Psychoactive Substances ◽  
Hydrothermal Route ◽  
Photoluminescence Quenching ◽  
Sensing System ◽  
Uv Lamp ◽  
Abused Drugs ◽  
Solid Ink Printing

Sensitive and selective assays are demanded for quantitation of new psychoactive substances such as 4-chloroethcathinone that is a π-conjugated keto compound. Carbon dots (C-dots) prepared from L-arginine through a hydrothermal route have been used for quantitation of 4-chloroethcathinone in aqueous solution and on C-dot-functionalized papers (CDFPs). To prepare CDFPs, chromatography papers, each with a pattern of 8 × 12 circles (wells), are first fabricated through a solid-ink printing method and then the C-dots are coated into the wells. π-Conjugated keto or ester compounds induce photoluminescence quenching of C-dots through an electron transfer process. At pH 7.0, the CDFPs allow screening of abused drugs such as cocaine, heroin and cathinones. Because of poor solubility of heroin and cocaine at pH 11.0, the C-dot probe is selective for cathinones. The C-dots in aqueous solution and CDFPs at pH 11.0 allow quantitation of 4-chloroethcathinone down to 1.73 mM and 0.14 mM, respectively. Our sensing system consisting of a portable UV-lamp, a smartphone and a low-cost CDFP has been used to detect cathinones, cocaine and heroin at pH 7.0, showing its potential for screening of these drugs in crime sites.

scholarly journals Detection of Ferric Ions and Catecholamine Neurotransmitters via Highly Fluorescent Heteroatom Co-Doped Carbon Dots

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3470
Author(s):  
Thi Hoa Le ◽  
Hyun Jong Lee ◽  
Ji Hyeon Kim ◽  
Sang Joon Park
Keyword(s):  
Carbon Dots ◽  
Fluorescence Quantum Yield ◽  
Limit Of Detection ◽  
Fluorescence Signal ◽  
Ferric Ions ◽  
Nitrogen And Phosphorus ◽  
Fluorescence Detector ◽  
Sensing System ◽  
Doped Carbon Dots ◽  
Co Doped

Carbon dots (CDs) demonstrate very poor fluorescence quantum yield (QY). In this study, with the help of a hydrothermal method, we combined CDs with nitrogen and phosphorus elements belonging to the VA group (in the periodic table) to form heteroatom co-doped CDs, i.e., nitrogen and phosphorus co-doped carbon dots (NPCDs). These displayed a significant improvement in the QY (up to 84%), which was as much as four times than that of CDs synthesized by the same method. The as-prepared NPCDs could be used as an “off-on” fluorescence detector for the rapid and effective sensing of ferric ions (Fe3+) and catecholamine neurotransmitters (CNs) such as dopamine (DA), adrenaline (AD), and noradrenaline (NAD). The fluorescence of NPCDs was “turned off” and the emission wavelength was slightly red-shifted upon increasing the Fe3+ concentration. However, when CNs were incorporated, the fluorescence of NPCDs was recovered in a short response time; this indicated that CN concentration could be monitored, relying on enhancing the fluorescence signal of NPCDs. As a result, NPCDs are considered as a potential fluorescent bi-sensor for Fe3+ and CN detection. Particularly, in this research, we selected DA as the representative neurotransmitter of the CN group along with Fe3+ to study the sensing system based on NPCDs. The results exhibited good linear ranges with a limit of detection (LOD) of 0.2 and 0.1 µM for Fe3+ and DA, respectively.

Facile Synthesis and Properties of Aqueous CdTe Quantum Dots for High-Sensitive Copper (II) Ion Detection

NANO ◽  
2017 ◽  
Vol 12 (12) ◽  
pp. 1750151 ◽  
Author(s):  
Yue Zheng ◽  
Hengshan Tang ◽  
Xiaoyu Wang ◽  
Ya Di ◽  
Kunling Lu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Limit Of Detection ◽  
Tap Water ◽  
High Sensitivity ◽  
Cdte Quantum Dots ◽  
Reaction Conditions ◽  
One Pot ◽  
Sensing System ◽  
Cdte Qds ◽  
Transmission Electron

The synthesis of aqueous MPA-capped CdTe quantum dots (QDs) via a facile one-pot route was developed. The particle size, optical properties and crystal structure of the as-synthesis QDs were investigated by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), UV-vis absorption and photoluminescence (PL) spectra, respectively. Meanwhile, the effect of reaction conditions, including reaction time, pH and the quantity of sodium citrate (SC) on the growth of CdTe QDs were discussed. Then, the obtained CdTe QDs were successfully used for the detection of trace Cu[Formula: see text] with high sensitivity and excellent selectivity. The fluorescence intensity of CdTe QDs with Cu[Formula: see text] concentration showed a linear relationship in the range from [Formula: see text] mol/L to [Formula: see text][Formula: see text]mol/L. The correlation coefficient (R) is 0.9980 and limit of detection (LOD) is [Formula: see text][Formula: see text]mol/L. Moreover, the concentration of Cu[Formula: see text] in tap water samples was determined based on this sensing system and the recovery test was satisfactory.

scholarly journals One-Pot Hydrothermal Synthesis of Carbon Dots as Fluorescent Probes for the Determination of Mercuric and Hypochlorite Ions

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1831
Author(s):  
Hsin Lee ◽  
Yen-Chang Su ◽  
Hsiang-Hao Tang ◽  
Yu-Sheng Lee ◽  
Jan-Yee Lee ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Fluorescent Probes ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Tap Water ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
One Pot ◽  
Fluorescence Emission Spectra

Nitrogen and sulfur codoped carbon dots (NSCDs) were synthesized via a one-pot hydrothermal method, and citric acid, ethylenediamine, and methyl blue were used as precursors. The obtained NSCDs were spherical with an average size of 1.86 nm. The fluorescence emission spectra of the NSCDs were excitation independent and emitted blue fluorescence at 440 nm with an excitation wavelength at 350 nm. The quantum yield of the NSCDs was calculated to be 68.0%. The NSCDs could be constructed as fluorescent probes for highly selective and sensitive sensing mercuric (Hg2+) and hypochlorite (ClO−) ions. As the addition of Hg2+ or ClO− ions to the NSCDs, the fluorescence intensity was effectively quenched due to dynamic quenching. Under the optimal conditions, the linear response of the fluorescence intensity ranged from 0.7 μM to 15 μM with a detection limit of 0.54 μM and from 0.3 μM to 5.0 μM with a limit of detection of 0.29 μM for Hg2+ and ClO− ions, respectively. Finally, the proposed method was successfully used for quantifying Hg2+ and ClO− ions in spiked tap water samples.

scholarly journals Green synthesis of surface-passivated carbon dots from the prickly pear cactus as a fluorescent probe for the dual detection of arsenic(iii) and hypochlorite ions from drinking water

RSC Advances ◽  
2018 ◽  
Vol 8 (53) ◽  
pp. 30455-30467 ◽  
Author(s):  
K. Radhakrishnan ◽  
P. Panneerselvam
Keyword(s):  
Drinking Water ◽  
Green Synthesis ◽  
Carbon Dots ◽  
Prickly Pear ◽  
Hydrothermal Route ◽  
One Pot ◽  
New Approach ◽  
Prickly Pear Cactus ◽  
Dual Detection ◽  
Pear Cactus

Efforts were made to develop a simple new approach for the green synthesis of surface-passivated carbon dots from edible prickly pear cactus fruit as the carbon source by a one-pot hydrothermal route.

scholarly journals Simultaneous Hydrolysis and Detection of Organophosphate by Benzimidazole Containing Ligand-Based Zinc(II) Complexes

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 714
Author(s):  
Gaber A. M. Mersal ◽  
Hamdy S. El-Sheshtawy ◽  
Mohammed A. Amin ◽  
Nasser Y. Mostafa ◽  
Amine Mezni ◽  
...  
Keyword(s):  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Organophosphorus Compounds ◽  
Organophosphorus Pesticides ◽  
Carbon Paste ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Carbon Past Electrode ◽  
Hydrolysis Of ◽  
Biomimetic Sensor

The agricultural use of organophosphorus pesticides is a widespread practice with significant advantages in crop health and product yield. An undesirable consequence is the contamination of soil and groundwater by these neurotoxins resulting from over application and run-off. Here, we design and synthesize the mononuclear zinc(II) complexes, namely, [Zn(AMB)2Cl](ClO4) 1 and [Zn(AMB)2(OH)](ClO4) 2 (AMB = 2-aminomethylbenzimidazole), as artificial catalysts inspired by phosphotriesterase (PTE) for the hydrolysis of organophosphorus compounds (OPs) and simultaneously detect the organophosphate pesticides such as fenitrothion and parathion. Spectral and DFT (B3LYP/Lanl2DZ) calculations revealed that complexes 1 and 2 have a square-pyramidal environment around zinc(II) centers with coordination chromophores of ZnN4Cl and ZnN4O, respectively. Both 1 and 2 were used as a modifier in the construction of a biomimetic sensor for the determination of toxic OPs, fenitrothion and parathion, in phosphate buffer by square wave voltammetry. The hydrolysis of OPs using 1 or 2 generates p-nitrophenol, which is subsequently oxidized at the surface of the modified carbon past electrode. The catalytic activity of 2 was higher than 1, which is attributed to the higher electronegativity of the former. The oxidation peak potentials of p-nitrophenol were obtained at +0.97 V (vs. Ag/AgCl) using cyclic voltammetry (CV) and +0.88 V (vs. Ag/AgCl) using square wave voltammetry. Several parameters were investigated to evaluate the performance of the biomimetic sensor obtained after the incorporation of zinc(II) complex 1 and 2 on a carbon paste electrode (CPE). The calibration curve showed a linear response ranging between 1.0 μM (0.29 ppm) and 5.5 μM (1.6 ppm) for fenitrothion and 1.0 μM (0.28 ppm) and 0.1 μM (0.028 ppm) for parathion with a limit of detection (LOD) of 0.08 μM (0.022 ppm) and 0.51 μM (0.149 ppm) for fenitrothion and parathion, respectively. The obtained results clearly demonstrated that the CPE modified by 1 and 2 has a remarkable electrocatalytic activity towards the hydrolysis of OPs under optimal conditions.

scholarly journals A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanhua Xun ◽  
Stephan Thomas Lane ◽  
Vassily Andrew Petrov ◽  
Brandon Elliott Pepa ◽  
Huimin Zhao
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
High Volume ◽  
N Gene ◽  
Testing System ◽  
Target Sequence ◽  
One Pot ◽  
Sequence Detection ◽  
Highly Sensitive ◽  
Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

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