scholarly journals Cyclic Voltammetry and Oxidation Rate Studies of Ferrous Gluconate Complex Solutions for Preparation of Chitosan-Tripolyphosphate Microparticles

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Noer Abyor Handayani ◽  
Elsa Anisa Krisanti ◽  
Sutrasno Kartohardjono ◽  
Kamarza Mulia

A proper understanding of the properties of iron could increase the effectiveness of programmes for alleviating iron deficiency. Recently, encapsulation has been considered an appropriate method for protecting iron from injurious reactions. However, several events may occur during encapsulation processes, including changes in the iron’s oxidation state. Oxidation of ferrous iron is not desirable since the intestines can only absorb iron in the ferrous form. In this study, a cyclic voltammetry method was applied to investigate the likelihood of ferrous gluconate oxidation for the preparation of chitosan-tripolyphosphate microparticles. Then, the electrochemical properties of ferrous gluconate were confirmed experimentally. The oxidation rate of ferrous gluconate is also discussed in this paper. All the experimental solutions were formulated in detail to produce conditions similar to those of microparticle production. Cyclic voltammetry analysis was conducted using a configuration of three electrodes connected to an electrochemical analyser. Graphite, platinum wire, and Ag/AgCl were employed as the auxiliary, working, and reference electrodes, respectively. The cyclic voltammetry results show that the observed potential for each anodic peak shifted negatively in the presence of chitosan and sodium tripolyphosphate. Moreover, the rate of ferrous oxidation tended to increase during 75 min of experiments due to the presence of chitosan and sodium tripolyphosphate. These behaviours indicate the transformation of ferrous iron to ferric iron during iron microparticle preparation. Furthermore, these findings suggest that spray drying is a preferable method to minimise the oxidation reaction.

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Intan Frina Utamiyanti

<p>The development of material-based glucose sensor SiO<sub>2</sub>-CuO using Screen Printed Carbon Electrode (SPCE) had been done. Three types of materials were used to detect glucose, i.e Multi Wall Carbon Nanotube (MWCNT)-SiO2-CuO, SiO2-CuO (A) dan SiO2-CuO (B). The differences composition of SiO<sub>2</sub>-CuO(A) and SiO<sub>2</sub>-CuO(B) occurred during the addition of NaOH in synthesis process of SiO2-CuO (B). The prepared materials were analyzed by Scanning Electron Microscopy (SEM), cyclic voltammetry method and chrono-amperometry. Cyclic voltammetry analysis was conducted at a potential range of -1.0 - 1.5 V with Ag/AgCl as reference electrode. The scan rate was 100 mV/sec and the potential was varied at (-0.6), (-0.5) and (-0.4) V, in which the duration of each analysis was 5 second. Based on the result of analysis, whether by SEM, cyclic voltammetry and chrono-amperometry, the SiO<sub>2</sub>-CuO (B) was found to be the best material for detection of glucose.</p>


2016 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Intan Frina Utamiyanti ◽  
Barlah Rumhayati ◽  
Ani Mulyasuryani

The development of material-based glucose sensor SiO<sub>2</sub>-CuO using Screen Printed Carbon Electrode (SPCE) had been done. Three types of materials were used to detect glucose, i.e Multi Wall Carbon Nanotube (MWCNT)-SiO2-CuO, SiO2-CuO (A) dan SiO2-CuO (B). The differences composition of SiO<sub>2</sub>-CuO(A) and SiO<sub>2</sub>-CuO(B) occurred during the addition of NaOH in synthesis process of SiO2-CuO (B). The prepared materials were analyzed by Scanning Electron Microscopy (SEM), cyclic voltammetry method and chrono-amperometry. Cyclic voltammetry analysis was conducted at a potential range of -1.0 - 1.5 V with Ag/AgCl as reference electrode. The scan rate was 100 mV/sec and the potential was varied at (-0.6), (-0.5) and (-0.4) V, in which the duration of each analysis was 5 second. Based on the result of analysis, whether by SEM, cyclic voltammetry and chrono-amperometry, the SiO<sub>2</sub>-CuO (B) was found to be the best material for detection of glucose.


2016 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Intan Frina Utamiyanti ◽  
Barlah Rumhayati ◽  
Ani Mulyasuryani

The development of material-based glucose sensor SiO<sub>2</sub>-CuO using Screen Printed Carbon Electrode (SPCE) had been done. Three types of materials were used to detect glucose, i.e Multi Wall Carbon Nanotube (MWCNT)-SiO2-CuO, SiO2-CuO (A) dan SiO2-CuO (B). The differences composition of SiO<sub>2</sub>-CuO(A) and SiO<sub>2</sub>-CuO(B) occurred during the addition of NaOH in synthesis process of SiO2-CuO (B). The prepared materials were analyzed by Scanning Electron Microscopy (SEM), cyclic voltammetry method and chrono-amperometry. Cyclic voltammetry analysis was conducted at a potential range of -1.0 - 1.5 V with Ag/AgCl as reference electrode. The scan rate was 100 mV/sec and the potential was varied at (-0.6), (-0.5) and (-0.4) V, in which the duration of each analysis was 5 second. Based on the result of analysis, whether by SEM, cyclic voltammetry and chrono-amperometry, the SiO<sub>2</sub>-CuO (B) was found to be the best material for detection of glucose.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2349
Author(s):  
Alain Salvador Conejo-Dávila ◽  
Marco Armando Moya-Quevedo ◽  
David Chávez-Flores ◽  
Alejandro Vega-Rios ◽  
Erasto Armando Zaragoza-Contreras

The development of anilinium 2-acrylamide-2-methyl-1-propanesulfonate (Ani-AMPS) monomer, confirmed by 1H NMR, 13C NMR, and FTIR, is systematically studied. Ani-AMPS contains two polymerizable functional groups, so it was submitted to selective polymerization either by free-radical or oxidative polymerization. Therefore, poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonic) [Poly(Ani-AMPS)] and polyaniline doped with 2-acrylamide-2-methyl-1-propanesulfonic acid [PAni-AMPS] can be obtained. First, the acrylamide polymer, poly(Ani-AMPS), favored the π-stacking of the anilinium group produced by the inter- and intra-molecular interactions and was studied utilizing 1H NMR, 13C NMR, FTIR, and UV-Vis-NIR. Furthermore, poly(Ani-AMPS) fluorescence shows quenching in the presence of Fe2+ and Fe3+ in the emission spectrum at 347 nm. In contrast, the typical behavior of polyaniline is observed in the cyclic voltammetry analysis for PAni-AMPS. The optical properties also show a significant change at pH 4.4. The PAni-AMPS structure was corroborated through FTIR, while the thermal properties and morphology were analyzed utilizing TGA, DSC (except PAni-AMPS), and FESEM.


1995 ◽  
Vol 49 (11) ◽  
pp. 1669-1676 ◽  
Author(s):  
Sahar F. Mahmoud ◽  
Stephen E. Bialkowski

In this research, laser-excited fluorescence was examined for sensitive detection of aqueous dityrosine. Samples were excited with a 6.3-mW, 325-nm helium-cadmium laser focused into a small volume-fluorescence cell with a 10-cm lens. The resulting fluorescence emission was collected perpendicular to the excitation and detected with two different schemes. An optical bandpass filter was used with a photomultiplier tube for sensitive quantitative measurement, while a photodiode array detector was used in conjunction with a spectrograph for qualitative characterization of fluorescence emission spectra. Dityrosine detection on the order of 2 × 10−11 M was obtained with the use of the photomultiplier tube with bandpass optical filter. The dityrosine fluorescence yield is found to vary with the solution pH, the relative concentrations of ferric and ferrous iron, and the amount of dissolved oxygen. A maximum fluorescence yield is observed for iron-free, oxygen-free alkaline solutions. Fluorescence quenching by oxygen is a cumulative photolysis effect that diminished fluorescence yield with increased irradiation time. Flowing the solutions minimized photolysis effects in oxygenated solutions. Quenching by ferrous and ferric iron is found to be due primarily to complex formation. The ferrous iron complex appears to have a fluorescence efficiency of ∼20% of the free dityrosine. The ferric iron dityrosine complex appears to have two ferric ions per molecule at low iron concentration. Other complexes may form at different concentrations. Solvent effects on dityrosine absorption and fluorescence spectra were also investigated. A red shift in dityrosine fluorescence maximum was observed in 1 M trichloroacetic acid and in N, N-dimethylformamide. The fluorescence emission maximum was shifted to the blue in acetonitrile and glacial acetic acid. These shifts were attributed to typical solvochromic behavior.


2016 ◽  
Vol 3 (5) ◽  
pp. 709-712 ◽  
Author(s):  
Hao Yuan ◽  
Richard R. Lunt ◽  
Gary J. Blanchard ◽  
Robert Y. Ofoli

2018 ◽  
Vol 181 ◽  
pp. 189-194
Author(s):  
Naomi J. Boxall ◽  
Ka Yu Cheng ◽  
Chris A. du Plessis ◽  
David Collinson ◽  
Christina Morris ◽  
...  

1991 ◽  
Vol 55 (378) ◽  
pp. 3-18 ◽  
Author(s):  
John C. Schumacher

AbstractThe ferromagnesian silicate minerals, such as garnets, pyroxenes, micas, and amphiboles, appear in a variety of geothermometers and geobarometers. Where complete chemical analyses are available and regardless of bulk composition (metamorphosed pelitic or mafic), the aforementioned minerals commonly contain ferric iron. In mineral analyses using the electron microprobe, ferric and ferrous iron are not distinguished, and all the iron is treated as FeO. In ferric Fe-bearing minerals, this treatment results in (1) low analytical sums and (2) excess cations in the mineral formulae. Assuming ideal stoichiometry (ideal formula cations and oxygens) allows direct ferric estimates in garnets and pyroxenes; amphiboles require additional assumptions concerning site occupancies, and, for micas, no acceptable constraint exists for a ferric estimate. Based on ferric iron determinations for some metamorphic ferromagnesian silicates, the proportion of ferric to total iron increases at higher XMg values. The influence of ferric estimates on T and P calculations depends on the model used and on the extent the ferric estimate alters the relative proportions of end-members. Several examples suggest that, in general, if ferric estimates (or determinations) are made, they should be made for all the relevant minerals.


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