A Switchable Sensor for Cu2+ and Zn2+ Based on Xanthene Moietymaking a Path for a Complex Molecular Encryption System Based on Color and Fluorescent Change

<p>Colorimetric and fluorescent detection methods for metal analytes has become a powerful tool for qualitative and quantitative analysis in the last decade due to their immediate output, cost-effectiveness, specificity/selectivity, zero interference, high detection limit, and application in practical samples. Sensing Cu²⁺, Ni^2+, or Zn²⁺ like analytes gained a lot of attention due to their significance in biological, medical, and environmental purposes. To account for this purpose, we synthesized and designed a colorimetric, fluorescent off-on, and reversible chemosensor <b>EYM</b> having xanthene as a signaling moiety and 4-carbamoyl-3-Butenoic acid as a receptor moiety. The <b>EYM</b> probe is then screened with Al³⁺, V³⁺, Na⁺, K⁺, Fe³⁺, Mg²⁺, Ca²⁺, Fe²⁺, Co²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Mn²⁺, Co³⁺, Pb²⁺, Cu²⁺, Pd²⁺, and V⁴⁺in DMSO: H₂O (4:1) solvent system where <b>EYM</b> shows absorbance change specifically for Cu²⁺ at 541nm changing from colorless to dark pink. The detection limit and association constant of the <b>EYM</b> probe for Cu²⁺ is 78.5nM and (6.013-5.947)´10⁹ M^-1, respectively. The coordination of Cu²⁺ with <b>EYM</b> is in (1:2: Ligand: Metal) stoichiometric ratio. The immediate saturation time (~2 sec) and low detection limit (78.5nM) of the EYH probe give competitiveness over other sensors in practical applicability in real-life samples detection of Cu²⁺. Not only this, the <b>EYM</b> sensor can switch from mono to bi to tri-functional sensor for Cu²⁺, Ni^2+, and Zn²⁺ with the stimuli of water in the DMSO solvent. The <b>EYM</b> shows specific abnormal fluorescent enhancement in contact with Zn²⁺ in DMSO solvent. The detection limit for Zn²⁺ is 79nM same as Cu²⁺ in a colorimetric assay. Switchable sensing is utilized to make complex molecular LOGIC GATE operations, including password-protected molecular encryption systems.</p>

A Switchable Sensor for Cu2+ and Zn2+ Based on Xanthene Moietymaking a Path for a Complex Molecular Encryption System Based on Color and Fluorescent Change

<p>Colorimetric and fluorescent detection methods for metal analytes has become a powerful tool for qualitative and quantitative analysis in the last decade due to their immediate output, cost-effectiveness, specificity/selectivity, zero interference, high detection limit, and application in practical samples. Sensing Cu²⁺, Ni^2+, or Zn²⁺ like analytes gained a lot of attention due to their significance in biological, medical, and environmental purposes. To account for this purpose, we synthesized and designed a colorimetric, fluorescent off-on, and reversible chemosensor <b>EYM</b> having xanthene as a signaling moiety and 4-carbamoyl-3-Butenoic acid as a receptor moiety. The <b>EYM</b> probe is then screened with Al³⁺, V³⁺, Na⁺, K⁺, Fe³⁺, Mg²⁺, Ca²⁺, Fe²⁺, Co²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Mn²⁺, Co³⁺, Pb²⁺, Cu²⁺, Pd²⁺, and V⁴⁺in DMSO: H₂O (4:1) solvent system where <b>EYM</b> shows absorbance change specifically for Cu²⁺ at 541nm changing from colorless to dark pink. The detection limit and association constant of the <b>EYM</b> probe for Cu²⁺ is 78.5nM and (6.013-5.947)´10⁹ M^-1, respectively. The coordination of Cu²⁺ with <b>EYM</b> is in (1:2: Ligand: Metal) stoichiometric ratio. The immediate saturation time (~2 sec) and low detection limit (78.5nM) of the EYH probe give competitiveness over other sensors in practical applicability in real-life samples detection of Cu²⁺. Not only this, the <b>EYM</b> sensor can switch from mono to bi to tri-functional sensor for Cu²⁺, Ni^2+, and Zn²⁺ with the stimuli of water in the DMSO solvent. The <b>EYM</b> shows specific abnormal fluorescent enhancement in contact with Zn²⁺ in DMSO solvent. The detection limit for Zn²⁺ is 79nM same as Cu²⁺ in a colorimetric assay. Switchable sensing is utilized to make complex molecular LOGIC GATE operations, including password-protected molecular encryption systems.</p>

A semicontinuous study on the ecotoxicity of atmospheric particles using a versatile aerosol concentration enrichment system (VACES): development and field characterization

Oxidative stress can be used to evaluate not only adverse health effects but also adverse ecological effects, but limited research uses eco-toxicological assay to assess the risks posed by particle matters to non-human biomes. One important reason might be that the concentration of toxic components of atmospheric particles is far below the high detection limit of eco-toxic measurement. To solve the rapid detection problem, we extended a versatile aerosol concentration enrichment system (VACES) for ecotoxicity aerosol measurement and firstly used VACES to provide a comparison of ecotoxicity between non-concentrated and concentrated aerosols in ambient air. In this study, the total concentration (number or mass), the concentration of chemical components and the ecotoxicity were all increased by approximately 7 to 10 times in VACES, making the detection of ecotoxicity above the baseline. The comparison of ecotoxicity data and PM2.5 concentration showed that low concentration was not matched with ecotoxicity, although high concentration corresponded to higher ecotoxicity. In addition, the higher saturation temperature in VACES caused a loss of particulate matter, of which nitrate accounted for about 18 %.

Electrochemical Characterization of Redox FeII/FeIII Mediated by ZrO2NPs/GCE Using Cyclic Voltammetry

In this article, experimental methods based on cyclic voltammetric technique were used to study the electrochemical analysis of a new modified electrode with zirconium dioxide molecules on the glassy carbon electrode (ZrO2NPs/GCE) to characterize iron ions K4[Fe(CN)6]. These methods also allowed the study of current peaks for oxidation reduction of Fe(II)/Fe(III) using potassium chloride (KCl) solution as electrolytes at different concentration, pH, scanning rates, and stability (reliability) of which these parameters are important in assessing oxidation properties. Also, the diffusion coefficient values of oxidation-reduction reaction for iron ions on the new sensor (ZrO2 NPs/GCE) was determined using Randles-Seveik equation as Dfa = 2.03 ×10-5 cm2 /sec and Dfc = 7.12 × 10-5 cm2 /sec, respectively. It was found the modified electrode ZrO2NPs/GCE acts as a good sensor with high detection limit of iron ions in electrolyte. It can be used the modified electrode in different electrochemical applications because of its higher conductivity.

Sandwiched gold/PNIPAm/gold microstructures for smart plasmonics application: towards the high detection limit and Raman quantitative measurements

A smart plasmonic SERS platform, comprising a layer of a stimuli-responsive polymer sandwiched between two gold layers, is reported.

Ion chromatography as highly suitable method for rapid and accurate determination of antibiotic fosfomycin in pharmaceutical wastewater

A rapid and accurate ion chromatography (IC) method (limit of detection as low as 0.06 mg L−1) for fosfomycin concentration determination in pharmaceutical industrial wastewater was developed. This method was compared with the performance of high performance liquid chromatography determination (with a high detection limit of 96.0 mg L−1) and ultraviolet spectrometry after reacting with alizarin (difficult to perform in colored solutions). The accuracy of the IC method was established in the linear range of 1.0–15.0 mg L−1 and a linear correlation was found with a correlation coefficient of 0.9998. The recoveries of fosfomycin from industrial pharmaceutical wastewater at spiking concentrations of 2.0, 5.0 and 8.0 mg L−1 ranged from 81.91 to 94.74%, with a relative standard deviation (RSD) from 1 to 4%. The recoveries of effluent from a sequencing batch reactor treated fosfomycin with activated sludge at spiking concentrations of 5.0, 8.0, 10.0 mg L−1 ranging from 98.25 to 99.91%, with a RSD from 1 to 2%. The developed IC procedure provided a rapid, reliable and sensitive method for the determination of fosfomycin concentration in industrial pharmaceutical wastewater and samples containing complex components.

Results compared for tricyclic antidepressants as assayed by liquid chromatography and enzyme immunoassay.

The tricyclic antidepressants amitriptyline, nortriptyline, imipramine, and desipramine in serum of patients taking one of the drugs were quantified in two laboratories by high-performance liquid chromatography (HPLC) and enzyme-multiplied immunoassay (EMIT; Syva). Results for split samples were highly correlated, but EMIT gave higher results in most cases, and the slopes of the correlation lines for each analyte were greater than 1. Detection limits for the two procedures were such that 18% of the EMIT results for the drug(s) were considered negative, as compared with 4% of the HPLC results. Additional assay of desmethyl or hydroxy antidepressant metabolites by HPLC did not explain the higher EMIT results. The relatively high detection limit for EMIT greatly limits its use in therapeutic drug monitoring, where low concentrations of tricyclic antidepressants are as important as high ones for dose adjustment or determination of compliance. Other problems with EMIT measurement of tricyclic antidepressants are discussed.