Synthesis of rGO/TiO2/CdS Nanocomposites and its Enhanced Photoelectrochemical Performance in Determination of Parathion-Methyl

NANO ◽  
2018 ◽  
Vol 13 (05) ◽  
pp. 1850054
Author(s):  
Jian-Jun Shi ◽  
Yan Wang ◽  
Li-Rong Meng ◽  
Jing-Chun Zhu ◽  
Rui-Wen Shu ◽  
...  
Keyword(s):  
Solvothermal Method ◽  
High Sensitivity ◽  
Alkaline Condition ◽  
Optimal Conditions ◽  
Excellent Performance ◽  
Photoelectrochemical Performance ◽  
Sensing System ◽  
The Matrix ◽  
Cds Nanocomposites

A photoelectrochemical (PEC) sensor for the determination of organophosphate pesticides (OPs) was developed based on rGO/TiO2/CdS photoactive nanomaterials. The rGO/TiO2/CdS nanocomposites were prepared by solvothermal method and electrochemical deposition technique successively. The morphologies and structures of the as-prepared nanocomposites were extensively investigated by SEM and XRD. In alkaline condition, p-nitrophenol as the hydrolysate of parathion-methyl (PM) could be obtained by a simple hydrolyzation process. Under optimal conditions, the rGO/TiO2/CdS NPs modified ITO electrode exhibited a good PEC performance toward the hydrolysate of PM. The photocurrent intensity was enhanced with the increase of the concentration of the hydrolysate of PM. The proposed PEC method could detect PM in the range from 0.05[Formula: see text]nmol L[Formula: see text] to 10[Formula: see text]nmol L[Formula: see text] with a detection limit of 0.02[Formula: see text]nmol L[Formula: see text] ([Formula: see text]). Thus, the excellent performance of the rGO/TiO2/CdS nanocomposites serve as the matrix of the sensor, which provides a new way for the fabrication of high-sensitivity PEC sensing system.

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.

scholarly journals Simultaneous Determination of Rimsulfuron and Haloxyfop-P-methyl and Its Metabolite Haloxyfop in Tobacco Leaf by LC-MS/MS

2019 ◽  
Vol 102 (5) ◽  
pp. 1632-1640
Author(s):  
Yurong Yu ◽  
Shan Zhao ◽  
Ya Yang ◽  
Ya Chen ◽  
Daimei Qiu ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Weed Management ◽  
Matrix Effects ◽  
High Sensitivity ◽  
Tobacco Leaf ◽  
Extraction Solvent ◽  
Nicotiana Tabacum L ◽  
The Matrix ◽  
Pretreatment Conditions

Abstract Background: Tobacco (Nicotiana tabacum L.), is an important economic crop. In China, the use of rimsulfuron and haloxyfop-P-methyl herbicides for weed management during the planting period is necessary to improve the production of tobacco. Objective: To establish and validate a quick, easy, cheap, effective, rugged, and safe LC-MS/MS method to determine rimsulfuron, haloxyfop-P-methyl, and haloxyfop in tobacco leaf samples. Methods: We optimized MS/MS conditions and chromatographic conditions for optimal detection conditions. The extraction solvent and sorbent were optimized, and the analysis of variance was applied to analyze the pretreatment method to obtain the optimal pretreatment conditions. Results: The validation results showed that the proposed method exhibited good linearity (R2 > 0.9978), satisfactory recovery (72.51–101.60%) and low LOQ (0.02–1.00 mg/kg). The matrix effects of the three analytes in the two tobacco leaf matrixes were different. The dissipation results showed that the half-lives of rimsulfuron and haloxyfop-P-methyl in fresh tobacco leaf samples were ranged from 2.4 to 3.7 days. The final residues of rimsulfuron, haloxyfop-P-methyl, and haloxyfop in flue-cured tobacco leaf samples were all lower than the LOQ. Conclusions: The results demonstrate that the developed method could be used to detect rimsulfuron, haloxyfop-P-methyl, and haloxyfop in tobacco leaf matrixes. Highlights: A method for simultaneous determination of rimsulfuron, haloxyfop-P-methyl, and haloxyfop in tobacco leaf samples with high sensitivity has been established for the first time.

scholarly journals Development of the High Sensitivity and Selectivity Method for the Determination of Histamine in Fish and Fish Sauce from Vietnam by UPLC-MS/MS

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Quang Hieu Tran ◽  
Thanh Tan Nguyen ◽  
Kim Phuong Pham
Keyword(s):  
Limit Of Detection ◽  
High Sensitivity ◽  
Fish Sauce ◽  
Limit Of Quantification ◽  
Fish Samples ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Sensitivity And Selectivity ◽  
Liquid Chromatographic

A selective, sensitive, and rapid method by using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the determination of histamine in fish and fish sauce was developed. The optimal conditions of liquid chromatographic separation and mass spectroscopy of histamine have also been investigated. The linear ranges of the method were 20.0 ÷ 1000 ng/mL, and the corresponding correlation coefficient was 0.9993. Mean recoveries of the analyte at three spike levels (low, medium, and high) were within the range of 98.5% ÷ 102.5% (n = 7). The limit of detection (LOD) and limit of quantification (LOQ) values were 3.83 and 11.50 ng/mL for the fish sauce sample and 4.71 and 14.12 ng/mL for the fish sample, respectively. The influence of the matrix effect on the accuracy, repeatability, and recovery of the method was negligible. The recommended method was applied to determine the content of this substance in 21 fish sauce samples and 4 kinds of fish samples, which were collected from Ho Chi Minh City, Vietnam, in 2019.

Fluorescent sensing of sulfide ions based on papain-directed gold nanoclusters

2015 ◽  
Vol 39 (12) ◽  
pp. 9306-9312 ◽  
Author(s):  
Lichao Wang ◽  
Guiqiu Chen ◽  
Guangming Zeng ◽  
Jie Liang ◽  
Haoran Dong ◽  
...  
Keyword(s):  
Natural Water ◽  
Water Samples ◽  
Gold Nanoclusters ◽  
Fluorescence Sensing ◽  
Excellent Performance ◽  
Fluorescent Sensing ◽  
Sensing System ◽  
Natural Water Samples ◽  
Sulfide Ions

This fluorescence sensing system showed excellent performance and could be applied to the determination of S2− in natural water samples.

Experimental Investigation on Determination of Chitosan by Spectrophotometry

2012 ◽  
Vol 554-556 ◽  
pp. 1895-1900 ◽  
Author(s):  
Si Hui Wu ◽  
Song Yan Hu ◽  
Gui Dong Huang ◽  
Wei Shan Pan ◽  
Cheng Lu Yu ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Sulfuric Acid ◽  
Alcohol Solution ◽  
Alkaline Condition ◽  
Boiling Water Bath ◽  
Optimal Conditions ◽  
Average Recovery ◽  
Mixed Acid ◽  
Ultrasound Assisted

Chitosan is a natural basic polysaccharide, currently which have no a very effective way to determine its content. In this paper, we used mixed acid and ultrasound-assisted with chitosan which hydrolyzed into glucosamine, under alkaline condition acetyl acetone may react with paradimethylaminobenzaldehyde acid alcohol solution to form red compound, which was measured at 525nm by spectrophotometry. More appropriate technological conditions have been determined. The results showed that the optimal conditions for quantity of chitosan was 2mg, 0.168mol/L hydrochloric acid was 0.8ml, 75% sulfuric acid was 3.5ml, in boiling water bath for 30min, supersonic for 60min at 50 °C, the average recovery was 96.9±3.24%, the content of chitosan was 87.89±1.02%, the production rate of chitosan was 84.79±0.99%. The results show that the mentioned method is easy and effective for the quantitative analysis of chitosan by spectrophotometry.

CdSe Quantum Dots Decorated by 3-Aminobenzeneboronic Acid as Fluorescence Probe for Glucose

2011 ◽  
Vol 306-307 ◽  
pp. 1338-1341
Author(s):  
Shao Wei Wang ◽  
Xia Ona Zhang ◽  
Jing Hua Yu
Keyword(s):  
Quantum Dots ◽  
Fluorescence Probe ◽  
High Sensitivity ◽  
Cdse Quantum Dots ◽  
Optimal Conditions ◽  
Cdse Qds ◽  
Relative Standard ◽  
Sensitivity And Selectivity

A simple route to the production of high-quality CdSe quantum dots (QDs) is presented. The characterization of CdSe QDs was measured by Zetasizer Nano ZS, ultraviolet-visible spectoscopy and fluorospectrophotometer. The CdSe QDs were decorated by 3-Aminobenzeneboronic acid to obtain good fluorescent characteristic. Under the optimal conditions, the decreased normalized absorbance was linear to the concentration of glucose from 1.0×10−7 to 2.9×10−6 mol·L-1with a detection limit of 5.0´10-8mol·L-1. The relative standard deviation (RSD) for the determination of 1.0×10-7mol·L-1was 1.4 % by 11 replicate determination. In this paper, the fluorescent behavior of glucose with the decorated CdSe QDs was studied, and it is found that the system has a high sensitivity and selectivity for analysis of glucose.

scholarly journals MoS2/CdS Heterostructure for Enhanced Photoelectrochemical Performance under Visible Light

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 379 ◽  
Author(s):  
Guannan He ◽  
Yimin Zhang ◽  
Qinyu He
Keyword(s):  
Solvothermal Method ◽  
Photogenerated Electron ◽  
Molybdenum Sulfide ◽  
High Rate ◽  
Cds Nanoparticles ◽  
Mos2 Nanosheets ◽  
Photoelectrochemical Performance ◽  
Cds Nanocomposites ◽  
Original Crystal ◽  
Facile Solvothermal Method

High-rate recombination of photogenerated electron and hole pairs will lead to low photocatalytic activity. Constructing heterostructure is a way to address this problem and thus increase the photoelectrochemical performance of the photocatalysts. In this article, molybdenum sulfide (MoS2)/cadmium sulfide (CdS) nanocomposites were fabricated by a facile solvothermal method after sonication. The CdS nanoparticles immobilized on the MoS2 sheet retained the original crystal structure and morphology. The composites exhibit higher photoelectrochemical properties compared with pure MoS2 nanosheets or CdS powder. When the precursor concentration of CdS is 0.015 M, the MoS2/CdS composites yield the highest photocurrent, which is enhanced nearly five times compared with pure CdS or MoS2. The improved photoelectrochemical performance can be ascribed to the increase of light harvest, as well as to the heterostructure that decreases the recombination rate of the photogenerated electron and hole pairs.

scholarly journals New UHPLC-QqQ-MS/MS Method for the Rapid and Sensitive Analysis of Ascorbic and Dehydroascorbic Acids in Plant Foods

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1632 ◽  
Author(s):  
Nieves Baenas ◽  
Francisco J. Salar ◽  
Raúl Domínguez-Perles ◽  
Cristina García-Viguera
Keyword(s):  
Matrix Effect ◽  
High Performance ◽  
High Selectivity ◽  
Dehydroascorbic Acid ◽  
High Sensitivity ◽  
Practical Application ◽  
Quadrupole Mass ◽  
Internal Standards ◽  
The Matrix

A new method using ultra high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS) methodology was developed for the determination of ascorbic acid (AA) and dehydroascorbic acid (DHAA) contents in liquid and solid vegetable samples. The advantages of this method are speed, high sensitivity and practical application. In accordance with these advantages, the present method allows the simultaneous determination of AA and DHAA without previous reduction/derivatization of DHAA and without the use of internal standards in the samples. This is of high interest in routine analysis, providing a simpler sample preparation, as well as enhanced accuracy and robustness. Its validation included selectivity, sensitivity and linearity, precision and accuracy, matrix effect, and recovery. The results showed high selectivity and sensitivity, with calibration curves ranging from 10 to 500 ng mL−1 and from 50 to 500 ng mL−1 for AA and DHAA, respectively. Appropriate dilutions for each sample are necessary to avoid the matrix effect with accepted recoveries.

scholarly journals Gold Nanocage-Based Electrochemical Sensing Platform for Sensitive Detection of Luteolin

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2309 ◽  
Author(s):  
Xiaobao Li ◽  
Ruyi Zou ◽  
Yanyan Niu ◽  
Wei Sun ◽  
Taiming Shao ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Carbon Ionic Liquid Electrode ◽  
Optimal Conditions ◽  
Oxidation Peak ◽  
Chemically Modified ◽  
Sensing System ◽  
Redox Peak ◽  
Sensing Platform ◽  
Redox Peak Current

A simple and sensitive electrochemical sensor was developed for the detection of tracelevels of luteolin. The sensoris based on a novel type of chemically modified electrode: gold nanocage (AuNCs)-modified carbon ionic liquid electrode (CILE). To construct this electrochemical sensing platform for luteolin, CILE is initially prepared by using 1-hexylpyridinium hexafluorophosphate as the binder and then AuNCs are coated on the surface of CILE to fabricate AuNCs-modified CILE (AuNCs/CILE). Electrochemical studies have shown that AuNCs/CILE can exhibit enhanced electrocatalytic activity toward the redox reaction of luteolin, therefore, the redox peak current of luteolin can be greatly improved, resulting in the high sensitivity of the developed sensor. Under the optimal conditions, the oxidation peak currents of the sensor increase linearly with an increase in the luteolin concentration in a range from 1 to 1000 nM with a detection limit of 0.4 nM, which is lower than those of most reported electrochemical luteolin sensors. Moreover, the reproducibility, precision, selectivity, and stability of this sensor are excellent. Finally, the sensing system was applied to the analysis of luteolin-spiked drug samples and the recovery in all cases was 95.0–96.7%, indicating the potential application of this simple, facile, and sensitive sensing system in pharmaceutical analysis.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

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