scholarly journals Tuned Cd2+ Selectivity: Showcase of Electronic and Regio-Effect of π-Extended Di-2-Picolylamine-Substituted Quinoline-Based Tolans

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 917
Author(s):  
Min-Sung Ko ◽  
P. Sankara Rao ◽  
Dong-Gyu Cho
Keyword(s):  
Metal Ions ◽  
Steric Hindrance ◽  
Limit Of Detection ◽  
Energy Difference ◽  
Turn On ◽  
Fluorescence Titration ◽  
Metal Selectivity ◽  
Substituted Effect ◽  
Phosphate Buffered Saline ◽  
Pbs Phosphate Buffered Saline

π-Extended di-2-picolylamine (DPA)-substituted 8-hydroxyquinoline (8-HQ) tolans (2) were synthesized for testing electronic and regio-effects. The electron-poor CN-tolan (2b) showed clear selectivity for Cd2+ (>>Zn2+) over other metal ions via turn-on fluorescence, while the electron-rich MeO-tolan (2a) displayed no clear metal selectivity. Furthermore, considering that there was no significant energy difference between the Cd2+ complexes of 1 and 2b, the intended regio-effect (7- vs. 5-substituted effect) did not induce steric hindrance. Thus, the regio-effect is mainly electronic. Considering the above, 2a and 2b constitute a complete showcase in which electronic and regio-effects modulate the metal selectivity. The fluorescence titration of 2b (10 mM) with Cd2+ showed that the limit of detection (LOD) of the Cd2+-selective 2b was 158 nM in PBS (phosphate-buffered saline) (10 mM, pH 7.2) containing 50% MeOH.

scholarly journals Development of tBu-phenyl acetamide appended thiacalix[4]arene as “Turn-ON” Fluorescent Probe For Selective Recognition of Hg(II) Ions

2021 ◽  
Author(s):  
Ashukumar Verma ◽  
Krunal Modi ◽  
Shuvankar Dey ◽  
Anita Kongor ◽  
Manthan Panchal ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Metal Ions ◽  
Limit Of Detection ◽  
Bathochromic Shift ◽  
Computational Modelling ◽  
Selective Recognition ◽  
Strong Electron ◽  
Tert Butyl ◽  
Turn On ◽  
Binding Stoichiometry

Abstract Herein, a novel N-(4-(tert-butyl)-phenyl)-2-chloroacetamide functionalized thiacalix[4]arene architecture, viz TCAN2PA has been synthesized and the sensing behaviour towards metal ions was explored. The probe, TCAN2PA displayed a “Turn-ON” fluorescence response towards Hg(II) ions in acetonitrile over a series of competing common metal ions. A bathochromic shift in absorption band along with a significant “Turn-ON” fluorescence behaviour of TCAN2PA was observed upon interaction with Hg(II) ions. The lower rim modification of thiacalixarene with N-(4-(tert-butyl)-phenyl)-2-chloroacetamide actively contributes toward the fluorescence property due to the presence of strong electron-donating aryl amido substituent. Fluorescence titration experiments were conducted to find out the limit of detection and to understand binding stoichiometry as well. The electron transfer interactions between the electron-rich TCAN2PA host with Hg(II) ions have been postulated which is also supported by computational modelling insights.

scholarly journals Anodic Stripping Voltammetry with the Hanging Mercury Drop Electrode for Trace Metal Detection in Soil Samples

Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 107
Author(s):  
Kequan Xu ◽  
Clara Pérez-Ràfols ◽  
Amine Marchoud ◽  
María Cuartero ◽  
Gastón A. Crespo
Keyword(s):  
Metal Ions ◽  
Limit Of Detection ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Hanging Mercury Drop Electrode ◽  
Mercury Drop Electrode ◽  
Redox Active ◽  
Active Metal ◽  
Metal Detection ◽  
Trace Metal Detection

The widely spread use of the hanging mercury drop electrode (HMDE) for multi-ion analysis is primarily ascribed to the following reasons: (i) excellent reproducibility owing to the easy renewal of the electrode surface avoiding any hysteresis effect (i.e., a new identical drop is generated for each measurement to be accomplished); (ii) a wide cathodic potential window originating from the passive hydrogen evolution and solvent electrolysis; (iii) the ability to form amalgams with many redox-active metal ions; and (iv) the achievement of (sub)nanomolar limits of detection. On the other hand, the main controversy of the HMDE usage is the high toxicity level of mercury, which has motivated the scientific community to question whether the HMDE deserves to continue being used despite its unique capability for multi-metal detection. In this work, the simultaneous determination of Zn2+, Cd2+, Pb2+, and Cu2+ using the HMDE is investigated as a model system to evaluate the main features of the technique. The analytical benefits of the HMDE in terms of linear range of response, reproducibility, limit of detection, proximity to ideal redox behavior of metal ions and analysis time are herein demonstrated and compared to other electrodes proposed in the literature as less-toxic alternatives to the HMDE. The results have revealed that the HMDE is largely superior to other reported methods in several aspects and, moreover, it displays excellent accuracy when simultaneously analyzing Zn2+, Cd2+, Pb2+, and Cu2+ in such a complex matrix as digested soils. Yet, more efforts are required towards the definitive replacement of the HMDE in the electroanalysis field, despite the elegant approaches already reported in the literature.

scholarly journals Highly sensitive and selective colorimetric detection of dual metal ions (Hg2+ and Sn2+) in water: an eco-friendly approach

RSC Advances ◽  
2021 ◽  
Vol 11 (24) ◽  
pp. 14700-14709
Author(s):  
Rintumoni Paw ◽  
Moushumi Hazarika ◽  
Purna K. Boruah ◽  
Amlan Jyoti Kalita ◽  
Ankur K. Guha ◽  
...  
Keyword(s):  
Metal Ions ◽  
Ag Nanoparticles ◽  
Limit Of Detection ◽  
Colorimetric Detection ◽  
Garlic Extract ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Dual Metal

Synthesis of Ag nanoparticles using Allin based garlic extract for highly sensitive and selective detection of metal ions Hg2+ and Sn2+ in water. The limit of detection (LoD) for Hg2+ and Sn2+ ions were found as 15.7 nM and 11.25 nM respectively.

Chromogenic ‘naked eye’ and fluorogenic ‘turn on’ sensor for mercury metal ion using thiophene-based Schiff base

RSC Advances ◽  
2015 ◽  
Vol 5 (81) ◽  
pp. 65731-65738 ◽  
Author(s):  
Divya Singhal ◽  
Neha Gupta ◽  
Ashok Kumar Singh
Keyword(s):  
Schiff Base ◽  
Binding Affinity ◽  
Metal Ion ◽  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Naked Eye ◽  
Turn On

2-((3-Methylthiophen-2-yl)methyleneamino)benzenethiol (Probe 1) is selective for Hg2+. The binding affinity of Hg2+ with Probe 1 was confirmed by DFT and electrochemical behaviour. The limit of detection was 20 μM with 2 : 1 stoichiometry of 1 + Hg2+ complex.

A benzothiazole-based fluorescence turn-on sensor for copper(II)

2021 ◽  
Author(s):  
Gyeongjin Kim ◽  
Donghwan Choi ◽  
Cheal Kim
Keyword(s):  
Charge Transfer ◽  
Limit Of Detection ◽  
Theoretical Calculations ◽  
Enhanced Fluorescence ◽  
Turn On ◽  
Fluorescent Response ◽  
Chelation Enhanced Fluorescence ◽  
Fluorescence Turn On ◽  
Internal Charge Transfer ◽  
Internal Charge

Abstract A new benzothiazole-based chemosensor BTN (1-((Z)-(((E)-3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazono)methyl)naphthalen-2-ol) was synthesized for the detection of Cu2+. BTN could detect Cu2+ with “off-on” fluorescent response from colorless to yellow irrespective of presence of other cations. Limit of detection for Cu2+ was determined to be 3.3 µM. Binding ratio of BTN and Cu2+ turned out to be a 1:1 with the analysis of Job plot and ESI-MS. Sensing feature of Cu2+ by BTN was explained with theoretical calculations, which might be owing to internal charge transfer and chelation-enhanced fluorescence processes.

A Highly Sensitive and Label-Free Microbead-Based ‘Turn-On’ Colorimetric Sensor for the Detection of Mercury(II) in Urine Using a Peroxidase-Like Split G-Quadruplex–Hemin DNAzyme

2018 ◽  
Vol 71 (12) ◽  
pp. 945
Author(s):  
Xin Fu ◽  
He Zhang ◽  
Jie Zhang ◽  
Shi-Tong Wen ◽  
Xing-Cheng Deng
Keyword(s):  
Standard Deviation ◽  
Base Pair ◽  
Limit Of Detection ◽  
Label Free ◽  
Turn On ◽  
Highly Sensitive ◽  
Relative Standard ◽  
G Quadruplex ◽  
Catalytically Active ◽  
Partial Cdna

A highly sensitive and label-free microbead-based ‘turn-on’ assay was developed for the detection of Hg2+ in urine based on the Hg2+-mediated formation of intermolecular split G-quadruplex–hemin DNAzymes. In the presence of Hg2+, T–T mismatches between the two partial cDNA strands were stabilized by a T–Hg2+–T base pair, and can cause the G-rich sequences of the two oligonucleotides to associate to form a split G-quadruplex which is able to bind hemin to form the catalytically active G-quadruplex–hemin DNAzyme. This microbead-based ‘turn-on’ process allows the detection of Hg2+ in urine samples at concentrations as low as 0.5 pM. The relative standard deviation and recovery are 1.2–3.9 and 98.7–103.2%, respectively. The remarkable sensitivity for Hg2+ is mainly attributed to the enhanced mass transport ability that is inherent in homogeneous microbead-based assays. Compared with previous developments of intermolecular split G-quardruplex–hemin DNAzymes for the homogeneous detection of Hg2+ (the limit of detection was 19nM), a signal enhancement of ~1000 times is obtained when such an assay is performed on the surface of microbeads.

scholarly journals Using Thermolytic Solution of Anionic - Decorated Gqds as Fluorescence Turn on-off Sensor for Selective Screening Test of Metal Ions

2018 ◽  
Vol 34 (1) ◽  
pp. 55-63 ◽  
Author(s):  
Khanitta Saenwong ◽  
Chawangorn Putthasehn ◽  
Atipa Tunsawat ◽  
Prawit Nuengmatcha ◽  
Saksit Chanthai
Keyword(s):  
Metal Ions ◽  
Screening Test ◽  
Selective Screening ◽  
Turn On ◽  
Fluorescence Turn On

scholarly journals Enzyme Method-Based Microfluidic Chip for the Rapid Detection of Copper Ions

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1380
Author(s):  
Binfeng Yin ◽  
Xinhua Wan ◽  
Changcheng Qian ◽  
A. S. M. Muhtasim Fuad Sohan ◽  
Teng Zhou ◽  
...  
Keyword(s):  
Metal Ions ◽  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Copper Ions ◽  
Practical Applications ◽  
Enzyme Method ◽  
In Series ◽  
High Concentrations ◽  
Biochemical Detection ◽  
Seawater Samples

Metal ions in high concentrations can pollute the marine environment. Human activities and industrial pollution are the causes of Cu2+ contamination. Here, we report our discovery of an enzyme method-based microfluidic that can be used to rapidly detect Cu2+ in seawater. In this method, Cu2+ is reduced to Cu+ to inhibit horseradish peroxidase (HRP) activity, which then results in the color distortion of the reaction solution. The chip provides both naked eye and spectrophotometer modalities. Cu2+ concentrations have an ideal linear relationship, with absorbance values ranging from 3.91 nM to 256 μM. The proposed enzyme method-based microfluidic chip detects Cu2+ with a limit of detection (LOD) of 0.87 nM. Other common metal ions do not affect the operation of the chip. The successful detection of Cu2+ was achieved using three real seawater samples, verifying the ability of the chip in practical applications. Furthermore, the chip realizes the functions of two AND gates in series and has potential practical implementations in biochemical detection and biological computing.

scholarly journals A multifunctional selective “turn-on” fluorescent chemosensor for detection of Group IIIA ions Al3+, Ga3+ and In3+

2018 ◽  
Vol 17 (9) ◽  
pp. 1247-1255 ◽  
Author(s):  
Hyo Jung Jang ◽  
Ji Hye Kang ◽  
Dongju Yun ◽  
Cheal Kim
Keyword(s):  
Metal Ions ◽  
Fluorescent Chemosensor ◽  
Selective Recognition ◽  
Turn On

A versatile chemosensor was developed for highly distinguishable and selective recognition of group IIIA metal ions (Al3+, Ga3+ and In3+).

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