scholarly journals A Naked-Eye Visible Colorimetric and Ratiometric Chemosensor Based on Schiff Base for Fluoride Anion Detection

2020 ◽  
Author(s):  
Liu Yang ◽  
Yu-Long Liu ◽  
Cheng-Guo Liu ◽  
Ying Fu ◽  
Fei Ye
Keyword(s):  
Schiff Base ◽  
Limit Of Detection ◽  
Fluoride Anion ◽  
Dmso Solution ◽  
Binding Model ◽  
Anion Detection ◽  
Real Samples ◽  
Color Changes ◽  
Naked Eye ◽  
Ratiometric Probe

A dual-platform colorimetric and ratiometric chemosensor, namely 6-(2-hydroxynaphthalen)-N-n-butyl-naphthalimide (HNA), based on Schiff base constructed from N-n-butyl-4-amino-1,8-naphthalimide and 2-hydroxy-1-naphthaldehyde has been designed and fabricated for detecting fluoride anion (F−) in DMSO solution. HNA is a colorimetic and ratiometric probe with superior selectivity and sensitivity. The color changes of HNA from yellow to purple was observed by the naked eyes in the presence of F−. The absorbance in the UV-Vis spectra of HNA was decreasing in 422 nm, while gradually increasing in 583 nm by adding F−. The limit of detection (LOD) of HNA for detecting F− is low to 0.61 μM and the binding model of HNA and F− is in 3:2 stoichiometry. Meanwhile, HNA can be used to detect F− in real samples. Finally, the mechanism of HNA for the detection of F− was investigated. The present work indicated that HNA would be a superior potential chemosensor in monitoring F− selectively and sensitively.

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.

scholarly journals Design and Characterization of Electrochemical Sensor for the Determination of Mercury(II) Ion in Real Samples Based upon a New Schiff Base Derivative as an Ionophore

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3020
Author(s):  
Salman S. Alharthi ◽  
Ahmed M. Fallatah ◽  
Hamed M. Al-Saidi
Keyword(s):  
Schiff Base ◽  
Response Time ◽  
Limit Of Detection ◽  
Polymeric Membrane ◽  
Indicator Electrode ◽  
Membrane Composition ◽  
Solution Ph ◽  
Real Samples ◽  
Wide Range

The present paper provides a description of the design, characterization, and use of a Hg2+ selective electrode (Hg2+–SE) for the determination of Hg2+ at ultra-traces levels in a variety of real samples. The ionophore in the proposed electrode is a new Schiff base, namely 4-bromo-2-[(4-methoxyphenylimino)methyl]phenol (BMPMP). All factors affecting electrode response including polymeric membrane composition, concentration of internal solution, pH sample solution, and response time were optimized. The optimum response of our electrode was obtained with the following polymeric membrane composition (% w/w): PVC, 32; o-NPOE, 64.5; BMPMP, 2 and NaTPB, 1.5. The potentiometric response of Hg2+–SE towards Hg2+ ion was linear in the wide range of concentrations (9.33 × 10–8−3.98 × 10–3 molL–1), while, the limit of detection of the proposed electrode was 3.98 × 10–8 molL–1 (8.00 μg L–1). The Hg2+–SE responds quickly to Hg2+ ions as the response time of less than 10 s. On the other hand, the slope value obtained for the developed electrode was 29.74 ± 0.1 mV/decade in the pH range of 2.0−9.0 in good agreement with the Nernstian response (29.50 mV/decade). The Hg2+–SE has relatively less interference with other metal ions. The Hg2+–SE was used as an indicator electrode in potentiometric titrations to estimate Hg2+ ions in waters, compact fluorescent lamp, and dental amalgam alloy and the accuracy of the developed electrode was compared with ICP–OES measurement values. Moreover, the new Schiff base (BMPMP) was synthesized and characterized using ATR–FTIR, elemental analysis, 1H NMR, and 13C NMR. The PVC membranes containing BMPMP as an ionophore unloaded and loaded with Hg(II) are reported by scanning electron microscope images (SEM) along with energy-dispersive X-ray spectroscopy (EDX) spectra.

scholarly journals Noval Dual-Emission Fluorescence Carbon Dots as a Ratiometric Probe for Cu2+ and ClO− Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1232
Author(s):  
Jiaqing Guo ◽  
Aikun Liu ◽  
Yutian Zeng ◽  
Haojie Cai ◽  
Shuai Ye ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Background Noise ◽  
Good Recovery ◽  
Ratiometric Fluorescence ◽  
Dual Emission ◽  
Simple Method ◽  
Real Samples ◽  
Nitrogen Doped ◽  
Probe Concentration ◽  
Ratiometric Probe

The use of carbon dots (CDs) with dual emission based on ratiometric fluorescence has been attracting attention in recent times for more accurate ion detection since they help avoid interference from background noise, probe concentration, and complexity. Herein, novel dual-emission nitrogen-doped CDs (NCDs) were prepared by a simple method for Cu2+ and ClO- detection. The NCDs showed excellent anti-interference ability and selectivity for different emissions. In addition, a good linear relationship was observed between the fluorescence intensity (FI) of the NCD solutions in different emissions with Cu2+ (0–90 μM) and ClO- (0–75 μM). The limits of both Cu2+ detection and ClO- were very low, at 17.7 and 11.6 nM, respectively. The NCDs developed herein also showed a good recovery rate in water for Cu2+ and ClO− detection. Hence, they are expected to have a more extensive application prospect in real samples.

scholarly journals Effect of Citric Acid on Color Changes of Calcium Silicate-Based Cements an In Vitro Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2339
Author(s):  
Joanna Metlerska ◽  
Till Dammaschke ◽  
Mariusz Lipski ◽  
Irini Fagogeni ◽  
Anna Machoy-Mokrzyńska ◽  
...  
Keyword(s):  
Citric Acid ◽  
Calcium Silicate ◽  
In Vitro Study ◽  
Vitro Study ◽  
Color Measurement ◽  
Color Changes ◽  
Naked Eye ◽  
Root Canal Irrigants ◽  
The Difference

The aim of the present in vitro study was to investigate the effects of 10% and 40% citric acid (CA) on the color of calcium silicate–based cements (CSCs) in comparison to the effects of common root canal irrigants. Samples of six CSCs (n = 6)—ProRoot MTA (Dentsply, Tulsa, OK, USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), MTA Plus (Avalon Biomed Inc, by Prevest Denpro Limited, Jammu, India), MTA Repair HP (Angelus, Londrina, PR, Brazil), Ortho MTA (BioMTA, Seoul, Korea), and Retro MTA (BioMTA, Seoul, Korea)—were immersed in 10% and 40% CA as well as 15% EDTA, 2% NaOCl, 2% CHX, and 0.9% NaCl for 15 min, 1 h, and 24 h. ΔE values, representing the difference between the final and baseline values of the color components, were then determined using a VITA Easyshade Compact 5.0 spectrophotometer. Naked-eye evaluation of the changes in color and structures of the materials was performed using our own scale. Upon immersion of the materials in both 10% and 40% CA, there were statistically significant differences between spectrophotometric color measurement results for all CSCs (P < 0.05). However, CA does not cause dark discoloration, observable with the naked eye, of any of the materials, such as NaOCl and CHX. Significant statistical differences were also found between all CSCs in terms of submersion duration (P < 0.05). CA, which could be an alternative to EDTA use, caused greater CSCs discoloration and changed some of their structures. Unless required by the therapeutic procedure, clinicians should pay attention to the fact that the irrigant may affect the CSCs discoloration and minimize the contact time of irrigant with CSCs.

scholarly journals Recent Advancements in Enzyme-Based Lateral Flow Immunoassays

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3358
Author(s):  
Donato Calabria ◽  
Maria Maddalena Calabretta ◽  
Martina Zangheri ◽  
Elisa Marchegiani ◽  
Ilaria Trozzi ◽  
...  
Keyword(s):  
Lateral Flow ◽  
Qualitative Information ◽  
Eye Color ◽  
Commercial Success ◽  
Color Changes ◽  
Naked Eye ◽  
Future Developments ◽  
Highly Sensitive ◽  
Critical Overview ◽  
Detection Technologies

Paper-based lateral-flow immunoassays (LFIAs) have achieved considerable commercial success and their impact in diagnostics is continuously growing. LFIA results are often obtained by visualizing by the naked eye color changes in given areas, providing a qualitative information about the presence/absence of the target analyte in the sample. However, this platform has the potential to provide ultrasensitive quantitative analysis for several applications. Indeed, LFIA is based on well-established immunological techniques, which have known in the last year great advances due to the combination of highly sensitive tracers, innovative signal amplification strategies and last-generation instrumental detectors. All these available progresses can be applied also to the LFIA platform by adapting them to a portable and miniaturized format. This possibility opens countless strategies for definitively turning the LFIA technique into an ultrasensitive quantitative method. Among the different proposals for achieving this goal, the use of enzyme-based immunoassay is very well known and widespread for routine analysis and it can represent a valid approach for improving LFIA performances. Several examples have been recently reported in literature exploiting enzymes properties and features for obtaining significative advances in this field. In this review, we aim to provide a critical overview of the recent progresses in highly sensitive LFIA detection technologies, involving the exploitation of enzyme-based amplification strategies. The features and applications of the technologies, along with future developments and challenges, are also discussed.

scholarly journals Phthalocyanine-Functionalized Magnetic Silica Nanoparticles as Anion Chemosensors

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1632
Author(s):  
João M. M. Rodrigues ◽  
Andreia S. F. Farinha ◽  
Zhi Lin ◽  
José A. S. Cavaleiro ◽  
Augusto C. Tome ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Dimethyl Sulfoxide ◽  
Silica Nanoparticles ◽  
Hybrid Material ◽  
Limit Of Detection ◽  
Active Material ◽  
Anion Detection ◽  
Anionic Species ◽  
Magnetic Silica ◽  
Magnetic Silica Nanoparticles

Anionic species are one of the most common pollutants in residual and freshwaters. The presence of anthropogenic anions in water drastically increases the toxicity to living beings. Here, we report the preparation of a new optical active material based on tri(tosylamino)phthalocyanines grafted to ferromagnetic silica nanoparticles for anion detection and removal. The new unsymmetrical phthalocyanines (Pcs) proved to be excellent chemosensors for several anions (AcO−, Br−, Cl−, CN−, F−, H2PO4−, HSO4−, NO2−, NO3−, and OH−) in dimethyl sulfoxide (DMSO). Furthermore, the Pcs were grafted onto magnetic nanoparticles. The resulting novel hybrid material showed selectivity and sensitivity towards CN−, F−, and OH− anions in DMSO with limit of detection (LoD) of ≈4.0 µM. In water, the new hybrid chemosensor demonstrated selectivity and sensitivity for CN− and OH− anions with LoD of ≈0.2 µM. The new hybrids are easily recovered using a magnet, allowing recyclability and reusability, after acidic treatment, without losing the sensing proprieties.

Syntheses and crystal structures of guanidine hydrochlorides with two Schiff base functions as efficient colorimetric and selective sensors for fluoride

2018 ◽  
Vol 73 (8) ◽  
pp. 601-609 ◽  
Author(s):  
Bei Wang ◽  
Pei-Zhi Zhang ◽  
Xin Chen ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang
Keyword(s):  
Optical Properties ◽  
Schiff Base ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Guanidinium Chloride ◽  
Visible Absorption ◽  
X Ray ◽  
Color Changes ◽  
Base Functions ◽  
Magnetic Resonances

AbstractA series of guanidinium chloride derivatives have been synthesized by condensation of 1,3-diaminoguanidine monohydrochloride with heteroaromatic formaldehydes in good yields. All compounds were characterized by nuclear magnetic resonances and infrared spectroscopies, and the molecular structures of four compounds were determined by single crystal X-ray diffraction. The optical properties of these guanidinium chloride derivatives with fluoride anions were investigated, showing selective color changes from colorless to yellow or orange, red-shifted in the ultraviolet/visible absorption spectra.

scholarly journals A multi-colorimetric probe to discriminate between heavy metal cations and anions in DMSO–H2O with high selectivity for Cu2+ and CN−: study of logic functions and its application in real samples

RSC Advances ◽  
2021 ◽  
Vol 11 (47) ◽  
pp. 29466-29485
Author(s):  
Eunike Hamukwaya ◽  
Johannes Naimhwaka ◽  
Veikko Uahengo
Keyword(s):  
Heavy Metal ◽  
Schiff Base ◽  
Reaction Mechanism ◽  
High Selectivity ◽  
Colorimetric Probe ◽  
Real Samples ◽  
Heavy Metal Cations ◽  
H Nmr ◽  
Vis Spectroscopy ◽  
Logic Functions

A ditopic multi-colorimetric probe based on the phenylpridyl-thioic moiety (EN) was synthesized via a Schiff base reaction mechanism and characterized using 1H NMR and UV-vis spectroscopy.

Photophysical properties of a D–π-A Schiff base and its applications in the detection of metal ions

2018 ◽  
Vol 47 (38) ◽  
pp. 13730-13738 ◽  
Author(s):  
Yang Kang ◽  
Zhuang Liao ◽  
Min Wu ◽  
Sai Li ◽  
De-Cai Fang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Photophysical Properties ◽  
Naked Eye ◽  
Dual Channel ◽  
Stimuli Sensitive

AIEE-active D–π-A Schiff-base H2L is stimuli-sensitive and acts as a dual channel chemosensor for Cu2+ ions and naked-eye probes for Mn2+ ions.

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