A simple method to construct a low-cost immunosensor based on a dithiol-functionalized polydopamine platform

2021 ◽  
Author(s):  
Bo Liu ◽  
Luanying Yang ◽  
Gang Wang ◽  
Sha He ◽  
Xiaobo Wang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Linear Response ◽  
Low Cost ◽  
Covalent Immobilization ◽  
The Self ◽  
Simple Method ◽  
Low Detection Limit

A simple and low-cost electrochemical CEA immunosensor was investigated via the self-polymerization of dopamine and a dithiol compound spacer for the covalent immobilization of antibodies. The designed CEA immunosensor exhibited a linear response and a low detection limit.

Insecticide Residues on 1972 U.S. Auction-Market Tobacco

1975 ◽  
Vol 8 (1) ◽  
Author(s):  
J. J. Domanski ◽  
P. L. Haire ◽  
T.J. Sheets
Keyword(s):  
Detection Limit ◽  
Auction Market ◽  
Insecticide Residues ◽  
Low Detection Limit ◽  
Average Residue ◽  
The Individual ◽  
In Fire

AbstractAverage residue Ievels of DDT + TDE in flue-cured tobacco decreased from 6.1 ppm in 1970 to 0.85 ppm in 1972. DDT + TDE residues in Burley also dropped sharply from previous levels. In 1972 one sample from Kentucky contained 8.17 ppm; all other Burley samples were less than 0.25 ppm. DDT + TDE residues also declined in fire-cured and air-cured types; of these samples Tennessee dark air-cured tobacco contained the highest average residue (3.5 ppm of DDT + TDE). In 1972 over 90 % of the flue-cured samples were positive for toxaphene. Since each of our samples was a composite of tobacco from 10 farmers, we cannot conclude from this result that 90 % of the individual piles contained toxaphene. Significant amounts of toxaphene were found in other types also; for example, 50 % of the 1972 Burley samples had toxaphene concentrations greater than 0.5 ppm. Average endosulfan levels decreased between 1970 and 1972 in flue-cured and Burley tobaccos. However, in all of the dark air and dark fire-cured samples from Tennessee endosulfan residues exceeded 5 ppm. Average endrin residues were at or near the low detection limit in alI samples except fire-cured and dark air-cured tobacco from Tennessee; these averaged 0.26 and 0.17 ppm, respectively.

scholarly journals Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Mayra K. S. Monteiro ◽  
Djalma R. Da Silva ◽  
Marco A. Quiroz ◽  
Vítor J. P. Vilar ◽  
Carlos A. Martínez-Huitle ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Linear Response ◽  
High Performance ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Caffeine Concentration ◽  
Real Samples ◽  
Wide Range ◽  
Potential Use

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

scholarly journals A set of simple methods for detection and extraction of laminarinase

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ananthamurthy Koteshwara ◽  
Nancy V. Philip ◽  
Jesil Mathew Aranjani ◽  
Raghu Chandrashekhar Hariharapura ◽  
Subrahmanyam Volety Mallikarjuna
Keyword(s):  
Ammonium Sulfate ◽  
Ammonium Sulphate ◽  
Gold Standard ◽  
Direct Detection ◽  
Low Cost ◽  
Direct Analysis ◽  
Reducing Sugar ◽  
Ammonium Sulfate Precipitation ◽  
Simple Method ◽  
Functional Step

AbstractA carefully designed ammonium sulfate precipitation will simplify extraction of proteins and is considered to be a gold standard among various precipitation methods. Therefore, optimization of ammonium sulfate precipitation can be an important functional step in protein purification. The presence of high amounts of ammonium sulphate precludes direct detection of many enzymatically active proteins including reducing sugar assays (e.g. Nelson-Somogyi, Reissig and 3,5-dinitrosalicylic acid methods) for assessing carbohydrases (e.g. laminarinase (β (1–3)-glucanohydrolase), cellulases and chitinases). In this study, a simple method was developed using laminarin infused agarose plate for the direct analysis of the ammonium sulphate precipitates from Streptomyces rimosus AFM-1. The developed method is simple and convenient that can give accurate results even in presence of ammonium sulfate in the crude precipitates. Laminarin is a translucent substrate requiring the use of a stain to visualize the zones of hydrolysis in a plate assay. A very low-cost and locally available fluorescent optical fabric brightener Tinopal CBS-X has been used as a stain to detect the zones of hydrolysis. We also report simple methods to prepare colloidal chitin and cell free supernatant in this manuscript.

An ultra-highly sensitive and selective self-enhanced AIECL sensor for public security early warning in a nuclear emergency via a co-reactive group poisoning mechanism

2021 ◽  
Author(s):  
Ziyu Wang ◽  
Meiyun Xu ◽  
Nan Zhang ◽  
Jian-Bin Pan ◽  
Xinqi Wu ◽  
...  
Keyword(s):  
Detection Limit ◽  
Early Warning ◽  
High Selectivity ◽  
Public Security ◽  
Reactive Group ◽  
Low Detection Limit ◽  
Highly Sensitive ◽  
Vapor Sensors ◽  
Nuclear Emergency

A mechanism of co-reactive group poisoning (CGP) was discovered for designing efficient I2 vapor sensors for early warning of a nuclear emergency, which give an ultra-low detection limit of 0.13 ppt as well as high selectivity.

scholarly journals Self-coding: A method to assess semantic validity and bias when coding open-ended responses

2021 ◽  
Vol 8 (3) ◽  
pp. 205316802110317
Author(s):  
Rebecca A. Glazier ◽  
Amber E. Boydstun ◽  
Jessica T. Feezell
Keyword(s):  
Content Analysis ◽  
The Self ◽  
Bad Faith ◽  
Simple Method ◽  
Demographic Groups ◽  
Survey Questions ◽  
Coding Method ◽  
Significant Disagreement ◽  
Rich Data ◽  
Semantic Validity

Open-ended survey questions can provide researchers with nuanced and rich data, but content analysis is subject to misinterpretation and can introduce bias into subsequent analysis. We present a simple method to improve the semantic validity of a codebook and test for bias: a “self-coding” method where respondents first provide open-ended responses and then self-code those responses into categories. We demonstrated this method by comparing respondents’ self-coding to researcher-based coding using an established codebook. Our analysis showed significant disagreement between the codebook’s assigned categorizations of responses and respondents’ self-codes. Moreover, this technique uncovered instances where researcher-based coding disproportionately misrepresented the views of certain demographic groups. We propose using the self-coding method to iteratively improve codebooks, identify bad-faith respondents, and, perhaps, to replace researcher-based content analysis.

Bifunctional 4MBA mediated recyclable SERS-based immunoassay induced by photocatalytic activity of TiO2 nanotube arrays

2016 ◽  
Vol 18 (34) ◽  
pp. 23795-23802 ◽  
Author(s):  
Xiaolong Wang ◽  
Lu Zhou ◽  
Wei Lai ◽  
Tao Jiang ◽  
Jun Zhou
Keyword(s):  
Density Functional Theory ◽  
Photocatalytic Activity ◽  
Detection Limit ◽  
Uv Irradiation ◽  
Density Functional ◽  
Tio2 Nanotube Arrays ◽  
Tio2 Nanotube ◽  
Nanotube Arrays ◽  
Functional Theory ◽  
Low Detection Limit

We present a recyclable SERS-based immunoassay for CA19-9 with a low detection limit of 5 U mL−1. The linking between TiO2-NTs and 4MBA was destroyed by catalyzing 4MBA into 4-sulfobenzoate upon UV irradiation, which was clarified by UPLC/ESI-tqMS and density functional theory.

Electrochemical investigations of 8-hydroxydeoxyguanosine and its determination at an edge plane pyrolytic graphite electrode

RSC Advances ◽  
2016 ◽  
Vol 6 (3) ◽  
pp. 1722-1728 ◽  
Author(s):  
Pankaj Gupta ◽  
Munetaka Oyama ◽  
Rajendra N. Goyal
Keyword(s):  
Detection Limit ◽  
Electrochemical Oxidation ◽  
Graphite Electrode ◽  
Pyrolytic Graphite ◽  
Low Detection Limit ◽  
Pyrolytic Graphite Electrode

Electrochemical oxidation of 8-hydroxydeoxyguanosine (8-OHdG) and its detection with low detection limit is reported at pyrolytic graphite electrode.

An ultrasensitive electrochemical immunosensor for the detection of CD146 based on TiO2 colloidal sphere laden Au/Pd nanoparticles

The Analyst ◽  
2015 ◽  
Vol 140 (10) ◽  
pp. 3557-3564 ◽  
Author(s):  
Yaoguang Wang ◽  
Yueyun Li ◽  
Hongmin Ma ◽  
Aiping Guo ◽  
Bin Du ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Detection Limit ◽  
Pd Nanoparticles ◽  
Electrochemical Immunosensor ◽  
Loading Capacity ◽  
Colloidal Sphere ◽  
Low Detection Limit

An ultrasensitive electrochemical immunosensor was developed for detecting CD146. rGO-TEPA enhanced the loading capacity of Ab1 and facilitated the electron transfer. Au and Pd nanoparticles on the TiO2 colloidal sphere facilitated the decomposition of H2O2. The immunosensor exhibited an extremely low detection limit of 1.6 pg mL−1 for CD146.

Ultra-fast and low detection limit of H2S sensor based on hydrothermal synthesized Cu7S4-CuO Microflowers

2021 ◽  
pp. 130847
Author(s):  
Na wang ◽  
Rongrong Jin ◽  
Yue Zhou ◽  
Liupeng Zhao ◽  
Tianshuang Wang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Low Detection Limit
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