Bio

PDF Upload: 
application/pdf iconcv_marina_sept_2017.pdf

(Last updated: November 1, 2017)

Publications

2014

Marina, M.  2014.  Polyaniline and Polythiophene Modified Electrodes in Energy Storage Units with Hydrocarbon Gel/Bentonite/Sodium Chloride as Electrolyte Gel. IOSR Journal of Applied Chemistry. 7(5):63-80. Abstract

In this paper we present results obtained for energy storage units developed using polyaniline and polythiophene modified electrodes. The voltage potential profiles for recharge/discharge are either linear or exponential. Nucleation over-potential has been observed in some profiles where there is a phase transition. It is observed that hydrocarbon gel: bentonite electrolyte mixtures yielded relatively high initial voltages and that, this voltage also depended on the hydrocarbon: bentonite ratio. The potential decay profile for potential at Vo, 3/4Vo, 1/2Vo and 1/3Vo yielded linear and exponential curves for various hydrocarbon:bentonite mixtures.
The capacity (C) were 0.0014 Ah, for the 2:1 energy unit and 0.00035 Ah for the 3:1 energy unit.
The electric storage density (ESD) for the 2:1 and 3:1 energy units were 4.7 × 10-4 Ah/g and 8.8 × 10-5 Ah/g
Key words: Electronically conducting polymers, Bentonite, Hydrocarbon gel, discharge profile
Mukabi, M.  2014.  Surface Modified Electrodes Used In Cyclic Voltammetric Profiling Of Quinine An Anti-Malarial Drug. IOSR Journal of Applied Chemistry. 7(5):81-89. Abstract

In this paper electrochemical profiling of quinine, an effective anti- malarial drug administered to humans, was done using primarily the very versatile electrochemical technique- cyclic voltammetry. In the electro-analysis, the main supporting electrolyte used was sulphuric acid. The surface of the working electrode was modified using electronically conducting polymer- polyanailine and a clay montmorillonite- bentonite. Quinine and metal cation Cu2+, Co2+, Zn2+ and Sn2+ were also used to modify the electrode surface.The results obtained showed that quinine oxidation /reduction potential on bare carbon graphite electrode occured at 0.495V/0.300V and 0.015V (0.25M H2SO4 supporting electrolyte). Bentonite modified electrode gave 0.434V/0.480V (1M H2SO4 supporting electrolyte) and 0.360V/0.345V (1M HCl supporting electrolyte). A mechanistic pathway for the oxidation of quinine has also been proposed. It was also observed from the results obtained from studies on the effect of consumables such as tea, glycine and milk on quinine, that milk totally suppressed the redox process in quinine. Amino acids which are the building blocks in proteins and which is an important macromolecule in humans, does not affect significantly the redox process in quinine.
Cyclic voltammetric profiling of quinine interaction with metal cations such as Cu2+, Co2+, Zn2+ and Sn2+ and drugs such as paracetamol, acetyl salicylic acid, hydrocortisone and ferrous fumarate revealed interactions between the redox centers.
Key Words: Surface modified electrodes, cyclic voltammetry, polyaniline, bentonite and quinine
Mukabi, M.  2014.  Electrochemical Characterization of Amoxycillin, a Broad Spectrum Antibiotic on a Bentonite Host Matrix, Using Cyclic Voltammetry. IOSR Journal of Applied Chemistry. 7(5):50-58. Abstract

In this paper we report on the redox properties of amoxycillin , a broad spectrum anti biotic. on a bentonite modified working electrode. The CV obtained with ethanol is well defined and quasi reversible suggesting fast electrode kinetics. The oxidation peak in the case of water exhibits a shoulder at 0.195v and a well defined peak at 0.465v with a broad reduction peak approximated at 0.450v. In the case of ethanol, there is a single well defined oxidation peak at 0.480v and a well defined reduction peak at 0.330v.
Interaction of amoxycillin with metal cations (co2+, pb2+, fe2+cu2+), amino acids- methionine, leucine arginine and with hydrocortisone and paracetamol was assessed. The results obtained confirm the interactions of amoxil with these chemical substances. The amoxil redox potential is altered or inhibited in certain cases. This is informative given that these substances are commonly used together with amoxil as part of a prescription, notwithstanding the fact that the amino acids are iimportant macromolecules in the human biochemical/physiological system.
The UV-vis spectrophotometric analysis showed that, the absorbance of amoxil is a affected by electrolyte solution pH, probably an indication of the latter affecting the extent of conjugation in amoxil.
key words:amoxycillin (amoxil), antibiotic, bentonite, cyclic voltammetry
Mukabi, M.  2014.  Surface Modified Electrode Used In the Electro-Analysis of NAcetyl P-Aminophenol- A Pharmaceutical Drug. IOSR Journal of Applied Chemistry. 7(5):90-99. Abstract

In this paper we report on the electrochemical behavior of paracetamol or N-acetyl-p-aminophenol.
In the electro-analysis bare carbon graphite and bentonite modified working electrode has been used in
conjunction with cyclic voltammetry to study its redox properties. The results indicate that, the oxidation and
reduction potentials of paracetamol occur at 0.600V and 0.750V. The paracetamol cyclic voltammogram is
reversible.From the results obtained we observe that, paracetamol interacts with consumables such tea and
milk; metal ions such as CO2+ and Fe2+. It is also shown to interact with vitamin, ferrous fumarate and
hydrocortisone. The observed electrochemical behaviour of paracetamol, if replicated at the cellular level, can
give insight into its mechanistic and interactive pathways.
Keywords: N-acetyl-p-aminophenol (paracetamol), surface modified electrode, working electrode
Mukabi, M.  2014.  Sodium Thiosulphate, a Novel Electrocatalyst in the Electro-synthesis of Electronically Conducting Polymer-Polythiophene. IOSR Journal of Applied Chemistry. 7(5):73-85. Abstract

In this paper we report on the electrosynthesis of polythiophene from aqueous media with sulphuric acid as the supporting electrolyte. The redox features of polythiophene on a bare carbon graphite working electrode and on a clay montmorillonite host matrix is also reported. Co-polymerisation of polythiophene and polyaniline from an electrolyte media containing both aniline and thiophene monomers reveal that, the redox centres of the two polymers are independent, hence suggesting the formation of a bilayer, even though no charge rectification is observed.The role of sodium thiosulphate as a novel electrocatalyst which has led to a tremendous improvement in the polythiophene faradaic /redox process is also reported.
Key Words:Polythiophene, electronically conducting, clay montmorillonite (bentonite), electrocatalyst.
Mukabi, M.  2014.  Electro-Characterization of Polypyrolle Electrosynthesized on a Montmorillonite Host-Matrix, In Aqueous Media Containing Sulphuric Acid as Supporting Electrolyte. IOSR Journal of Applied Chemistry. 7(5):59-72. Abstract

In this paper polypyrolle has been electrosynthesised from an aqueous media containing the pyrolle monomer and sulphuric acid as the supporting electrolyte.
The redox properties of polypyrolle on carbon graphite working electrode and on a clay montmorillonite host matrix has also been reported.
The results obtained from plots of oxidative and reductive peak currents yield redox efficiencies above 95% for the polypyrolle redox process.
The polypyrolle redox process is also shown to be diffusion limited.
The reduction in the rate of electrodeposition of polypyrolle on a polyaniline loaded clay montmorillinite host-matrix, is a veiled confirmation of intercalation of the polyaniline in montmorillonite matrix.
KeyWords:Polypyrolle, Polyaniline, Electrosynthesised, Clay Montmorillonite (bentonite), Cyclicvoltammogram, Host matrix
D, O, H N, M M, D M, Y A.  2014.  Polyaniline and Polythiophene Modified Electrodes in Energy Storage Units with hydrocarbon gel/Bentonite/Sodium Chloride as Electrolyte Gel. Journal of Applied Chemistry.

2013

Mukabi, ML.  2013.  Introduction to Unit Operations. , Nairobi: University of Nairobi

UoN Websites Search