scholarly journals A Facile Aptasensor for Instantaneous Determination of Cadmium Ions Based on Fluorescence Amplification Effect of MOPS on FAM-Labeled Aptamer

Biosensors ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 133
Author(s):  
Yang Liu ◽  
Dongwei Zhang ◽  
Jina Ding ◽  
Kashif Hayat ◽  
Xijia Yang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Real Time ◽  
Sulfonic Acid ◽  
High Performance ◽  
Concentration Limit ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Amplification Effect ◽  
Fluorescence Amplification

Analytical performance and efficiency are two pivotal issues for developing an on-site and real-time aptasensor for cadmium (Cd2+) determination. However, suffering from redundant preparations, fabrications, and incubation, most of them fail to well satisfy the requirements. In this work, we found that fluorescence intensity of 6-carboxyfluorescein(FAM)-labeled aptamer (FAM-aptamer) could be remarkably amplified by 3-(N-morpholino)propane sulfonic acid (MOPS), then fell proportionally as Cd2+ concentration introduced. Importantly, the fluorescence variation occurred immediately after addition of Cd2+, and would keep stable for at least 60 min. Based on the discovery, a facile and ultra-efficient aptasensor for Cd2+ determination was successfully developed. The sensing mechanism was confirmed by fluorescence pattern, circular dichroism (CD) and intermolecular interaction related to pKa. Under the optimal conditions, Cd2+ could be determined rapidly from 5 to 4000 ng mL−1. The detection limit (1.92 ng mL−1) was also lower than the concentration limit for drinking water set by WHO and EPA (3 and 5 ng mL−1, respectively). More than a widely used buffer, MOPS was firstly revealed to have fluorescence amplification effect on FAM-aptamer upon a given context. Despite being sensitive to pH, this simple, high-performance and ultra-efficient aptasensor would be practical for on-site and real-time monitoring of Cd2+.

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

scholarly journals Determination of the bifenazate insecticide in apples and cucumbers by high performance liquid chromatography

2019 ◽  
Vol 55 (4) ◽  
pp. 422-428
Author(s):  
M. F. Zayats ◽  
S. M. Leschev
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Diode Array ◽  
The European Union ◽  
Optimal Conditions ◽  
Plant Materials ◽  
Ultraviolet Detection ◽  
Maximum Residue Level ◽  
Distribution Constants

Based on the distribution constants of biphenazate, obtained experimentally and also calculated from literature data on the solubility of biphenazate in water and organic solvents, as well as experimental data on the extraction of biphenazate from plant matrices by various extractants, we selected the optimal conditions for extracting biphenazate from apples and cucumbers. The conditions for the purification of the extracts were also selected. Acetonitrile in the presence of ammonium sulfate and hexane was used for extraction of the pesticide. Purification of extracts of plant materials was carried out by partitioning between hexane and water-acetonitrile mixture. The samples obtained after this treatment were pure enough to determine the residual amounts of biphenazate in them at the maximum residue level determined in Belarus and the countries of the European Union, or lower using widespread liquid chromatography with diode-array (ultraviolet) detection.

Development of a method for trace level determination of antibiotics in drinking water sources by high performance liquid chromatography-tandem mass spectrometry

2015 ◽  
Vol 7 (5) ◽  
pp. 1777-1787 ◽  
Author(s):  
Wenhuan Cheng ◽  
Lei Jiang ◽  
Ning Lu ◽  
Lei Ma ◽  
Xiaoyan Sun ◽  
...  
Keyword(s):  
Drinking Water ◽  
High Performance ◽  
Water Sources ◽  
Tandem Mass ◽  
Trace Level ◽  
Drinking Water Sources ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Harmful Effects

The presence of antibiotics in drinking water sources is worthy of concern regarding their potentially harmful effects on drinking water quality.

A real-time fluorescent sensor specific to Mg2+: crystallographic evidence, DFT calculation and its use for quantitative determination of magnesium in drinking water

2015 ◽  
Vol 44 (6) ◽  
pp. 2755-2762 ◽  
Author(s):  
Guangwen Men ◽  
Chunrong Chen ◽  
Shitong Zhang ◽  
Chunshuang Liang ◽  
Ying Wang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Quantitative Determination ◽  
Real Time ◽  
Dft Calculation ◽  
Fluorescent Sensor ◽  
Turn On ◽  
Quantitative Monitoring ◽  
Fluorescence Turn On

An “off-the-shelf” fluorescence “turn-on” Mg2+ chemosensor BCSA has been developed for real-time quantitative monitoring of magnesium in drinking water.

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