Polarographic Study of Lead in Potassium Thiocyanate Supporting Electrolyte

1954 ◽  
Vol 26 (7) ◽  
pp. 1119-1120 ◽  
Author(s):  
J. O. Hibbits ◽  
S. S. Cooper
Keyword(s):  
Supporting Electrolyte ◽  
Potassium Thiocyanate ◽  
Polarographic Study

Polarographic Study of the Electrode Reaction of Zn(II) in Formamide and Dimethylformamide

1975 ◽  
Vol 30 (5-6) ◽  
pp. 350-354 ◽  
Author(s):  
Sudhindra Swarup Sharma ◽  
Mukhtar Singh
Keyword(s):  
Kinetic Parameters ◽  
Organic Solvents ◽  
Metal Ion ◽  
Supporting Electrolyte ◽  
Electrode Reaction ◽  
Polarographic Study ◽  
Aqueous Mixtures ◽  
Diffusion Controlled ◽  
And Diffusion

The reduction of Zn(II) at the d.m.e. has been studied in aqueous mixtures of formamide and dimethylformamide. The general polarographic characteristics have been determined, using 0.1 M NaNO3 as the supporting electrolyte. The reduction of Zn(II) in these organic solvents is irreversible and diffusion controlled. The kinetic parameters, αna and kf,h have been calculated separately by KOTECKY and DELAHAY treatments. The change of polarographic characteristics and kinetic parameters is explained in terms of solvation of the metal ion in these solvents. The electrocapillary curves in the presence of these solvents have also been studied.

Room Temperature Flow Electrochemistry as a Means of Retaining the “Memory of Chirality” via Hofer Moest Type Reaction

2020 ◽  
Author(s):  
Tomas Hardwick ◽  
Rossana Cicala ◽  
Nisar Ahmed
Keyword(s):  
Continuous Flow ◽  
Room Temperature ◽  
Biological Activities ◽  
Supporting Electrolyte ◽  
Enantiomeric Excess ◽  
Flow Chemistry ◽  
Batch Processes ◽  
Enabling Technology ◽  
Chiral Compounds ◽  
Memory Of Chirality

<p>Many chiral compounds have become of great interest to the pharmaceutical industry as they possess various biological activities. Concurrently, the concept of “memory of chirality” has been proven as a powerful tool in asymmetric synthesis, while flow chemistry has begun its rise as a new enabling technology to add to the ever increasing arsenal of techniques available to the modern day chemist. Here, we have employed a new simple electrochemical microreactor design to oxidise an L-proline derivative at room temperature in continuous flow. Flow performed in microreactors offers up a number of benefits allowing reactions to be performed in a more convenient and safer manner, and even allow electrochemical reactions to take place without a supporting electrolyte due to a very short interelectrode distance. By the comparison of electrochemical oxidations in batch and flow we have found that continuous flow is able to outperform its batch counterpart, producing a good yield (71%) and a better enantiomeric excess (64%) than batch with a 98% conversion. We have, therefore, provided evidence that continuous flow chemistry has the potential to act as a new enabling technology to replace some aspects of conventional batch processes. </p>

Naphthoquinone-based hydrazone hybrids: synthesis and potent activity against cancer cell lines

2020 ◽  
Vol 16 ◽  
Author(s):  
Délis Galvão Guimarães ◽  
Arlan de Assis Gonsalves ◽  
Larissa Araújo Rolim ◽  
Edigênia Cavalcante Araújo ◽  
Victória Laysna dos Anjos Santos ◽  
...  
Keyword(s):  
Anticancer Activity ◽  
Cell Lines ◽  
Cancer Cell ◽  
Biological Activities ◽  
Supporting Electrolyte ◽  
Cancer Cell Lines ◽  
Molecular Structures ◽  
Cytotoxic Activities ◽  
Electrochemical Studies ◽  
Ic50 Values

Background: Natural naphthoquinones have shown diversified biological activities including antibacterial, antifungal, antimalarial, and cytotoxic activities. However, they are also compounds with acute cytotoxicity, immunotoxicity, carcinogenesis, and cardio- and hepatotoxicity, then the modification at their redox center is an interesting strategy to overcome such harmful activity. Objective: In this study, four novel semisynthetic hydrazones, derived from the isomers α- and β-lapachones (α and β, respectively) and coupled with the drugs hydralazine (HDZ) and isoniazid (ACIL), were prepared, evaluated by electrochemical methods and assayed for anticancer activity. Method: The semisynthetic hydrazones were obtained and had their molecular structures established by NMR, IR, and MS. Anticancer activity was evaluated by cell viability determined by reduction of 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT). The electrochemical studies, mainly cyclic voltammetry, were performed, in aprotic and protic media. Result: The study showed that the compounds 2, 3, and 4 were active against at least one of the cancer cell lines evaluated, being compounds 3 and 4 the most cytotoxic. Toward HL-60 cells, compound 3 was 20x more active than β-lapachone, and 3x more cytotoxic than doxorubicin. Furthermore, 3 showed an SI value of 39.62 for HL-60 cells. Compound 4 was active against all cancer cells tested, with IC50 values in the range 2.90–12.40 μM. Electrochemical studies revealed a profile typical of self-protonation and reductive cleavage, dependent on the supporting electrolyte. Conclusion: These results therefore indicate that compounds 3 and 4 are strong candidates as prototypes of new antineoplastic drugs.

Selective Sensing Platform Utilizing Graphitized Multi-Walled Carbon Nanotubes for Monitoring of Ondansetron and Paracetamol

2020 ◽  
Vol 16 ◽  
Author(s):  
Biljana Nigović ◽  
Iva Šimunić ◽  
Ana Mornar
Keyword(s):  
Carbon Nanotubes ◽  
Cation Exchange ◽  
Supporting Electrolyte ◽  
Polymer Concentration ◽  
Fixed Dose ◽  
Sensing Platform ◽  
Multi Walled Carbon Nanotubes ◽  
Electroanalytical Method ◽  
Walled Carbon Nanotubes

Background: Ondansetron and paracetamol are often co-administrated to prevent and treat nausea and vomiting caused by anaesthesia and to control of postoperative pain. In addition, ondansetron is used as the first-line antiemetic in paracetamol overdose. Therefore, selective and sensitive method for their simultaneous analysis is of a great importance. The electroanalytical methods are highly sensitive and offer many possibilities for new sensor platform design. However, at present, no electroanalytical method for simultaneous determination of these drugs has been proposed. Objective: The aim of this study was to develop a novel nanosensor for selective monitoring of ondansetron and paracetamol in pharmaceutical and biological samples without expensive and time-consuming pretreatments. Methods: The graphitized multi-walled carbon nanotubes embedded in a cation exchange polymer matrix was selected, among various surface functionalizations evaluated, to design novel sensor. Based on its excellent sensing performance, the first electroanalytical method was developed for rapid concurrent determination of investigated drugs. Results: The scanning electron microscopy study showed interlinked nanoporous network structure and highly enlarged active surface. The developed sensor facilitated electron transfer in the oxidation of both drugs and tremendously enhanced the adsorption capacity for ondasetron, thus exhibiting significant increase of drug responses and sensitivity. To obtain much sensitive response of investigated drugs the effect of pH values of supporting electrolyte, dispersed nanomaterial amount, the cation exchange polymer concentration, drop-casting volume of nanocomposite suspension, accumulation potential and deposition time on the peak current was evaluated. The developed electroanalytical method was validated and practical utility of the proposed nanosensor was tested. Conclusion: The developed sensor is promising sensing platform with a fast response time for analysis of ondansetron and paracetamol at very different concentration levels found in their fixed-dose combination and human serum sample after recommended daily doses showing its potential usage in pharmaceutical quality control and clinical research.

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