3 Methodology 3.1 Chemicals Chemicals will be obtained from Sigma-Aldrich. Graphite powder will be used as the raw material. Concentrated hydrochloric acid, sulphuric acid, potassium permanganate and hydrogen peroxide will be used for the oxidation process to oxidase graphite powder to graphite oxide. The next process will be to get the reduced graphene oxide. Hydrazine monohydrate will be used as the reductants. To make graphene as a glucose sensor, glucose, chitosan, phosphate buffer saline, potassium chloride, acetic acid, chloroplatinic acid, sulphuric acid, hydrogen peroxide, ascorbic acid and uric acid will be used. All solutions used in the glucose sensor experiment will be prepared with ultra-pure water. 3.2 Sample Preparation 3.2.1 Preparation of graphite oxide Graphite oxide will be synthesized by graphite powder through pre-oxidation and oxidation process based on Hummers and Hummers Improved method (Marcano et al., 2010). 20 g of graphite powder will be stirred in a heated solution of 30 ml H2SO4, 10 g K2S2O8 and 10 g P2O5 at 80°C for 30 minutes until dark blue mixture will be formed. The mixture will be cooled to 25°C for 6 hours. After that deionized water will be added and the ingredient will be filtered and washed until filtrate become neutral pH. Then, the filtrate will be dried overnight in vacuum desiccator at 25°C. 460 ml of concentrated H2SO4 will be used to oxidise the graphite in the ice bath after the drying process. KMnO4 will be added slowly with stirring and temperature of suspension will be maintained at 20°C.Then, the ice bath will be removed and the suspension will be heating up in an oil bath at 35°C for 2 hours until the suspension is thickening and effervescence paste in brownish grey colour will b... ... middle of paper ... ...at 3400 cm-1 by FTIR spectra. 3.4.3 Cyclic voltammetry (CV) Cyclic voltammetric and amperometic measurements will be performed to measure and detect the current at the working electrode and plotted versus the applied voltage. Electrochemical window of working electrode and electrolyte solution can examine the oxidation/reduction peak of redox species. If absence of redox analyte the cyclic voltammogram will form rectangular shape as voltage constantly varies the current will get to steady state. GO (0.5 g/mL) will be added in to 0.05M Sodium Perborate (PBS) solution. 30 continuous Cyclic voltammograms will be executed in the potential range between 0 to -1.5 V while scan rate at 30 mV/s. A cathodic peak will emerge at -1.0 V with an onset potential of -0.75 V during first cathodic potential scan. Cathodic peak will be disappearing completely after several cycles.
Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
The important parameters of a cyclic voltammogram are the magnitudes of anodic peak current (ipa), the cathodic peak current (ipc), the anodic peak potential (Epa) and cathodic peak potential (Epc). The basic shape of the current verses potential response for a cyclic voltammetry experiment as shown (Fig. 1.2). At the start of the experiment, the bulk solution contains only the oxidized form of the redox couple so that at potenials lower than the redox potential, i.e. the initial potential, there is no net conversion of oxidized species (O) into reduced species (R) (point A). As redox potential is approached, there is net cathodic current which increases exponentially with potential. As O is converted to R, concentration gradients are set up for both O and R, and diffusion occurs down these concentration gradients. At the cathodic peak (point B), the redox potential is sufficiently negative that any O that reaches the electrode surface is instantaneously reduced to R. Therefore,
ED is an electrical system utilizing ion exchange membranes. Ion exchange membranes have permselectivity similar to RO and NF membranes [6]. It is very important to understand the mechanism of permselectivity of ion exchange membranes to design ED system. The transport number ratio between target ion and standard ion has been treated to discuss the permselectivity of ion exchange membrane in ED system [7]. Recently, it was found that the ratio of transport number of several anions to chloride ion changed with the progress of electrodialysis. In this paper, a mechanism of permselectivity of ions in the electrodialysis system is theoretically discussed to make clear the reason why the transport number ratio changes with the progress of deionization in electodialysis process. In addition, the simple way to simulate ED system is proposed.
Schlesinger, Mordechay. "Electrochemistry Encyclopedia." Electroplating. Department of Physics, University of Windsor, Sept. 2002. Web. 17 Nov. 2013.
Needle-prick method was one of the earliest innovations in blood glucose monitoring and stayed the gold standard for a while. Right from the time, Ames Company released Dextrosix in 1965, this invasive method of blood glucose technology advanced rapidly. Even though the first glucose meter took six years to follow the Dextrostix blood strip, advancements followed rapidly. There were 2 companies in the market in 1971, but by 1987, there were 20 companies in market working on producing a better glucose meter. By 1987, as standard glucose monitoring technologies were hitting a plateau in terms of innovation, an effort to begin low-cost glucose monitoring started. This effort was directed at making the glucose monitors easily available at home, making patient use easier.
Transition metal oxide (TMO) materials contain transition element and oxygen. Both insulator and metal of poor quality are belongs to this group. It may be happens that the same material may give both types of transport properties. When either temperature or pressure is varying, then metal-insulator transition is possible. There are few superconductors are transition metal oxide. Valence electrons are present more than one shell in such type of compound. But the most of transition metal has one oxidation state. Transition metal oxides are not associated with activation energy; hence it is better than non-transition metal oxides. Transition metals have vacant d orbitals, so they are basically called catalyst. The metal surface adsorbed the reagent and the substrate and reagent are bound between them by a clamp called d orbitals. The vacant d-orbitals behaves similar like energy gap, hence transition metals have different colours.
The procedure for this experiment can be found in Inorganic Chemistry Lab Manual prepared by Dr. Virgil Payne.
Kirk, Julienne., Stegner, Jane., 2010. Journal of Diabetes Science and Technology: Self-Monitoring of Blood Glucose: Practical Aspects. Retrieved from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2864180/
October 22, 2004 wasn’t a particularly special day for Andre Geim and his colleague Kostyz Novoselov. Previously, a student had tried to separate graphite into ten or even one hundred layers but only succeeded in obtaining a specimen of one thousand layers. Then Geim had the brilliant idea of using Scotch tape to peel off individual layers of graphite. Geim and Kostyz took pieces of tape and manually separated the graphite until one layer remained (Lucibella 2). After hours of work and several pieces of tape with thin pieces of graphite on them, the final step was ready (Fuente). The tape was dissolved in a solution, leaving behind a thin flake on the surface of the solution. A substance previously unknown to mankind was created (Lucibella 2). This amazing material was named graphene. It is a sheet of atoms that can be picked up (Sheriff). Surprisingly, it resembles a honeycomb; the crystal lattice is composed solely of hexagons (Berger). Graphene is highly versatile, it has many interesting properties and it can be used in various electrical and medical applications.
brief overview on the structure and some properties of graphene, along with a presentation of graphene synthesis method and various applications.
Good morning/ afternoon ladies and gentleman, my name is Gurkaran Banipal, and my presentation is on Carbon Nanotubes or also known as CNTs. Did you know theses nanotubes are constructed with a length-to-diameter ratio of up to 132,000,000:1, significantly larger than for any other material present and they are lighter than plastic, stronger than steel, harder than diamond, and conduct electricity better than copper. Carbon nanotubes are a revolutionary development that has a very distinguished structure and unique properties which allows it to have significant applications in the fields of: nanotechnology, electronics, and other fields of materials science and technology that are applying to our everyday lives and improving them without us even noticing, and have a very small negative impact on our environment compared to their potential contributions to our world. The structure the CNTs possess is so unique and distinct it allows it to have very peculiar properties. The structure of the CNTs allows it to have very unique bonding properties, strength, electrical conductivity and Kinetic properties that are helping to change the world we know. I will discuss all of these properties, but first let me properly introduce you to these aforementioned Carbon Nanotubes.
Inside a standard lead acid battery it consists of two plates. There is a positive plate (+) which consists of lead peroxide (PbO₂) and a negative (-) plate which consists of lead (Pb). These two plates are placed into a dilute sulphuric acid (H₂SO₄) solution.
This topic has aroused my interest as now around the world, using fossil fuels to produce electricity is depleted and other alternatives are considered,which would create lower amount of greenhouse gases, and also because microbial fuel cells represent a clean and renewable energy source.I was also fascinated when we did chapter 9 of our syllabus which is oxidation and reduction I was so enthusiastic to see if there is another way of producing low voltage electricity without using electrodes and their salts/electrolytes. My aim in this experiment is to discover“How different types of sugar (Glucose,Fructose,Sucrose,Maltose and Galactose) used in a mi...
Metallurgy is the field of materials science and material engineering that studies the physical and chemical behaviour of metallic elements, their microstructure compounds and their mixtures, which are mostly known as alloy. Metallurgy can be refers as the technology of metals where science is applied to the production of metals, and the engineering of metal components for the uses of products for consumers and manufacturers.
It is the part of geology that is in charge of the study of rocks from the genetic point and from their relationships with other rocks, very closely related with magma. It is considered one of the main parts of geology. An igneous petrologist studies every aspect of magma in order to know