Quantitative Determination of Triglyceride by Photoactivated CdSe/ZnS Quantum Dots Through Fluorescence Assay

2008 ◽  
Vol 8 (7) ◽  
pp. 3434-3438 ◽  
Author(s):  
Chin-Ping Huang ◽  
Yaw-Kuen Li ◽  
Teng-Ming Chen
Keyword(s):  
Quantum Dots ◽  
Color Change ◽  
Low Cost ◽  
High Sensitivity ◽  
Assay System ◽  
Oil Refining ◽  
Quantitative Detection ◽  
Multiple Reactions ◽  
High Flexibility

The quantitative detection of triglycerides is an important issue for health inspection of metabolic disorders and for food and oil-refining industries. Many methods have been designed to approach this target, in which multiple reactions catalyzed by enzymes are normally coupled consecutively. In this study, we demonstrated a simple assay system containing lipase and photoactivated luminescent CdSe/ZnS quantum dots (QDs) for the quantitative detection of triglycerides. Photoactivated CdSe/ZnS QDs function as a sensitive "indicator" to reveal the minute acidity change of the assay system resulting from the enzymatic hydrolysis of triglycerides. By controlling the initial buffer condition of the assay system at 5, 10, or 20 mM phosphate buffer at pH 8.0, respectively, the quenching ratio of the QDs fluorescence intensity monitored at the maximum photoluminescence showed a linear correlation with the concentration of the examined triglyceride in the range of 0.02–6, 0.2–10, or 2–20 mM, respectively. The assay system also provides a convenient way to estimate triglyceride concentration by visualizing the color change of the QDs fluorescence. As compared to most of the existing methods, the system reported herein possessed many advantages, including simplicity, low cost, high flexibility, and high sensitivity. Furthermore, no complicated chemical modification or enzyme immobilization is needed.

scholarly journals Carbon Quantum Dots Prepared with Chitosan for Synthesis of CQDs/AuNPs for Iodine Ions Detection

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1043 ◽  
Author(s):  
Juanjuan Song ◽  
Li Zhao ◽  
Yesheng Wang ◽  
Yun Xue ◽  
Yujia Deng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Color Change ◽  
Colorimetric Method ◽  
High Sensitivity ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
Synthetic Process ◽  
Iodide Ions

Water-soluble and reductive carbon quantum dots (CQDs) were fabricated by the hydrothermal carbonization of chitosan. Acting as a reducing agent and stabilizer, the as-prepared CQDs were further used to synthesize gold nanoparticles (AuNPs). This synthetic process was carried out in aqueous solution, which was absolutely “green”. Furthermore, the CQDs/AuNPs composite was used to detect iodine ions by the colorimetric method. A color change from pink to colorless was observed with the constant addition of I− ions, accompanied by a decrease in the absorbance of the CQDs/AuNPs composite. According to the absorbance change, a favorable linear relationship was obtained between ΔA and I− concentration in the range of 20–140 μM and 140–400 μM. The detection limit of iodide ions, depending on the 3δ/slope, was estimated to be 2.3 μM, indicating high sensitivity to the determination of iodide. More importantly, it also showed good selectivity toward I− over other anion ions, and was used for the analysis of salt samples. Moreover, TEM results indicated that I− ions induced the aggregation of CQDs/AuNPs, resulting in changes in color and absorbance.

scholarly journals Determination of oroxin A, oroxin B, oroxylin A, oroxyloside, chrysin, chrysin 7-O-beta-gentiobioside, and guaijaverin in mouse blood by UPLC-MS/MS and its application to pharmacokinetics

2021 ◽  
Author(s):  
Zheng Yu ◽  
Fan Chen ◽  
Yinan Jin ◽  
Minyue Zhou ◽  
Xianqin Wang ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Sensitivity ◽  
Gradient Elution ◽  
Oroxylin A ◽  
Mouse Blood ◽  
Multiple Reactions ◽  
Caudal Vein ◽  
The Matrix ◽  
Positive Ion

Abstract In this study, a UPLC-MS/MS method was developed to measure the concentrations of the flavonoids oroxin A, oroxin B, oroxylin A, oroxyloside, chrysin, chrysin 7-O-beta-gentiobioside, and guaijaverin in the blank mouse blood, and the method was then used in the measurement of the pharmacokinetics of the compounds in mice. Oroxin A, oroxin B, oroxylin A, oroxyloside, chrysin, chrysin 7-O-beta-gentiobioside, and guaijaverin were administered intravenously at a dose of 5 mg kg−1, and the mouse blood (20 μL) was withdrawn from the caudal vein 0.08333, 0.25, 0.5, 1, 2, 4, 6, 8, and 10 h after administration. The mobile phase used for chromatographic separation by gradient elution was composed of acetonitrile and water (0.1% formic acid). The analytes were detected by operating in electrospray ionization (ESI) positive-ion mode using multiple reactions monitoring (MRM). The intra-day and inter-day accuracy ranged from 86.2 to 109.3%, the intra-day precision was less than 14%, and the inter-day precision was less than 15%. The matrix effect ranged from 85.3 to 111.3%, and the recovery of the analytes after protein precipitation were all above 78.2%. This method had the advantages of high sensitivity, accuracy, and recovery, and it had excellent selectivity, which enabled it to be applied to measuring the pharmacokinetics of the analytes in mice.

Detection of glutathione with an “off–on” fluorescent biosensor based on N-acetyl-l-cysteine capped CdTe quantum dots

The Analyst ◽  
2015 ◽  
Vol 140 (19) ◽  
pp. 6748-6757 ◽  
Author(s):  
Xuanping Tan ◽  
Jidong Yang ◽  
Qin Li ◽  
Qiong Yang
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
High Sensitivity ◽  
Cdte Quantum Dots ◽  
Fluorescent Biosensor

This paper reports a quantum dot (QD)-based “off–on” fluorescent biosensor specifically for the determination of glutathione (GSH) with high sensitivity.

scholarly journals A Simple Colorimetric Method for Determination of Ethanol in Exhaled Breath Condensate

2020 ◽  
Vol 27 (2) ◽  
pp. 297-301
Author(s):  
Fariba Pourkarim ◽  
Elaheh Rahimpour ◽  
Maryam Khoubnasabjafari ◽  
Vahid Jouyban-Gharamaleki ◽  
Sara Farhang ◽  
...  
Keyword(s):  
Color Change ◽  
High Reliability ◽  
Exhaled Breath Condensate ◽  
Colorimetric Method ◽  
Quantitative Detection ◽  
Exhaled Breath ◽  
Serum Samples ◽  
Catalyst Free ◽  
Breath Condensate

Background: Ethanol is considered as a toxic compound when used in excess amounts. The toxic concentration for ethanol was reported to be 1000 – 2000 μg.mL-1 in plasma and serum samples. The aim of the current study was to develop a rapid and catalyst free colorimetric method for determination of ethanol in exhaled breath condensate (EBC) sample. Methods: A redox reaction with dichromate-based colorimetric method was used for determination of ethanol in EBC. Results: The proposed method shows a good sensitivity and selectivity for ethanol in compared with other compounds and biomarkers existing in EBC. The color change can be easily observed by the naked eye in the presence of ethanol in the range of 300 - 8000 μg.mL-1. The quantitative detection of ethanol was fully validated and used for determination of ethanol in EBC of alcohol administrated individuals. Conclusion: This catalyst free colorimetric method has great potential for ethanol determination owing to many desirable properties such as high reliability, high sensitivity, and fast response time.

Recent Electrochemical Assays on Cephalosporins

2020 ◽  
Vol 16 (4) ◽  
pp. 337-349
Author(s):  
Leyla Karadurmus ◽  
Kaan Eşme ◽  
Nurgul K. Bakirhan ◽  
Sibel A. Ozkan
Keyword(s):  
Low Cost ◽  
Linear Sweep Voltammetry ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Electroanalytical Methods ◽  
Antibiotic Drugs ◽  
Short Time ◽  
Advanced Generation ◽  
Antibacterial Spectrum

: Antibiotics are an important class among drugs because they are a significant agent to deal with infections. Cephalosporins are a very important group of antibiotics in the β-lactam class. The cephalosporins are semisynthetic antibiotics derived from products of the fungus Cephalosporium. Cephalosporins are classified as first, second, third, fourth, and advanced generation, based largely on their antibacterial spectrum and stability to β-lactamases. Electrochemical methods have been used for the determination of cephalosporin just as used in the determination of many antibiotic drugs. Electroanalytical methods present generally high sensitivity, low cost, low requirements, ease of preparation of the samples in a very short time, and a short analysis time. The most commonly used types are cyclic voltammetry, differential pulse voltammetry, square wave voltammetry and linear sweep voltammetry. The aim of this review is to evaluate the advantages and uses of electroanalytical methods used in the determination of cephalosporins. In addition, current applications of the methods to the pharmaceutical analysis of cephalosporins will also be summarized in a table.

Biological Activity Test of Dendrobium Huoshanense and Its Application in the Detection of Environmental Pollutant Phenols

2021 ◽  
Vol 13 (7) ◽  
pp. 1205-1214
Author(s):  
Yujuan Wang ◽  
Jun Dai ◽  
Peipei Wei ◽  
Yongping Cai ◽  
Bangxing Han
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Reaction ◽  
High Sensitivity ◽  
Carbon Quantum Dots ◽  
Environmental Pollutant ◽  
One Step ◽  
New Type ◽  
Filtration Effect ◽  
Dendrobium Huoshanense

ABSTRACTIn this research, a new type of carbon quantum dot was prepared from Dendrobium huoshanense via one-step hydrothermal reaction at 200 °C for 6 h. The as-derived carbon quantum dots exhibited good fluorescence properties, with quantum yield of 23.57%. The extraction and determination of Dendrobium huoshanense enzymes activity were performed for different incubation times to study the theoretical reference for the dynamic changes of the main enzyme activity in the process of Dendrobium huoshanense growth and the solid processing industry. The results demonstrated that Dendrobium huoshanense was a low toxic carbon source material. Moreover, the prepared carbon quantum dots exhibited high sensitivity for the detection of nonylphenol, allowing a range of linear response of 0.5–50 µM (R2 = 0.9997). The detection limit was a slow as 95.32 nM. These results indicated that fluorescence internal filtration effect influenced nonylphenol-induced quenching of the Dendrobium huoshanense-carbon quantum dots fluorescence. The Dendrobium huoshanense-carbon quantum dots were successfully used to track nonylphenol in environmental samples. Therefore, their exploitation offers a promising approach for environmental pollutant detection.

scholarly journals Electrochemical Sensor for Rapid and Sensitive Detection of Tryptophan by a Cu2O Nanoparticles-Coated Reduced Graphene Oxide Nanocomposite

Biomolecules ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 176 ◽  
Author(s):  
Quanguo He ◽  
Yaling Tian ◽  
Yiyong Wu ◽  
Jun Liu ◽  
Guangli Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Low Cost ◽  
Supporting Electrolyte ◽  
Modified Electrodes ◽  
High Sensitivity ◽  
Experimental Conditions ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

In this paper, a nanocomposite of cuprous oxide and electrochemically reduced graphene oxide (Cu2O–ERGO) was prepared by a simple and low-cost method; hereby, a new method for the electrochemical determination of tryptophan (Trp) by this composite modified glassy carbon electrode (GCE) is proposed. The prepared materials and modified electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and cyclic voltammetry (CV). The results showed that Cu2O–ERGO/GCE had good electrocatalytic activity for Trp. The effects of supporting electrolyte, scanning rate, accumulation potential, and accumulation time on the determination of Trp were studied. Under the optimum experimental conditions, Trp was quantitatively analyzed by square-wave voltammetry (SWV). The oxidation peak current of Trp had a good linear relationship with its concentration in the range of 0.02–20 μM, and the detection limit was 0.01 μM (S/N = 3). In addition, the modified electrode has high sensitivity, good repeatability, and long-term stability. Finally, the proposed method has been successfully applied in the determination of Trp concentration in practical samples.

scholarly journals Highly Sensitive and Selective Colorimetric Detection of Creatinine Based on Synergistic Effect of PEG/Hg2+–AuNPs

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1424 ◽  
Author(s):  
Xia ◽  
Zhu ◽  
Bian ◽  
Li ◽  
Liu ◽  
...  
Keyword(s):  
Color Change ◽  
Limit Of Detection ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Peak Shift ◽  
Creatinine Concentration ◽  
Highly Sensitive ◽  
Coordination Effect ◽  
Bovine Serum Sample

A colorimetric sensor, based on the synergistic coordination effect on a gold nanoparticle (AuNP) platform has been developed for the determination of creatinine. The sensor selects citrate stabilized AuNPs as a platform, polyethylene glycol (PEG) as a decorator, and Hg2+ as a linkage to form a colorimetric probe system (PEG/Hg2−–AuNPs). By forming hydrogen bond between the oxygen-containing functional groups of PEG and citrate ions on the surface of AuNPs, this probe shows good stability. PEG coordinated with Hg2+ synergistically and specifically on the surface of dispersed AuNPs, and the existence of creatinine could induce the aggregation of AuNPs with a corresponding color change and an obvious absorption peak shift within 5 min. This PEG/Hg2+–AuNPs probe towards creatinine shows high sensitivity, and a good linear relationship (R2 = 0.9948) was obtained between A620–522 nm and creatinine concentration, which can achieve the quantitative calculations of creatinine. The limit of detection (LOD) of this PEG/Hg2+–AuNPs probe was estimated to be 9.68 nM, lower than that of many other reported methods (Supplementary Materials Table S3). Importantly, the sensitive probe can be successfully applied in a urine simulating fluid sample and a bovine serum sample. The unique synergistic coordination sensing mechanism applied in the designation of this probe further improves its high selectivity and specificity for the detection of creatinine. Thus, the proposed probe may give new inspirations for colorimetric detection of creatinine and other biomolecules.

Sign in / Sign up

Export Citation Format

Share Document