Sharif Digital Repository

In this thesis, in the first part, a promising electrochemical sensor was developed based on a layer by layer process by electropolymerization of pyrrole in the presence of new coccine (NC) as dopant anion on the surface of the CNTs pre-coated glassy carbon electrode (GCE). The modified electrode was used as a new and sensitive electrochemical sensor for voltammetric determination of sumatriptan (SUM). The results showed a remarkable increase in the anodic peak current of SUM in comparison to the bare GCE. In the second part, the electropolymerization of pyrrole was performed in the presence of Nitrazine Yellow (NY) as a dopant anion on the surface of the electrode precoated with CNTs. The... 

Nowadays, the inside needle capillary adsorption trap (INCAT) technique as a solventless sample preparation approach and alternative extraction method derived from SPME is gaining rising attentions. The INCAT and needle-trap devices are inexpensive, robust, reusable, and are applicable for sampling and analyzing suitable organic compounds from many different sample matrices. Compared to the fragile silica-based SPME fiber, the needle device is nearly impossible to break mechanically. In addition, the extraction medium possesses quite a large extraction phase volume and a powerful preconcentration capability. Similar to SPME, needle-like devices are particularly convenient for automation and... 

In the first part of thesis, the electropolymerization of pyrrole was performed in the presence of new coccine (NC) as a dopant anion on the surface of the electrode precoated with SWCNT. The modified electrode was used to study the voltammetric response of salbutamol (SAL). The results showed a remarkable increase in the anodic peak current of SAL in comparison to the bare GCE. The surface morphology PPY/CNT/GCE was thoroughly characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Under the optimized analysis conditions, the modified electrode showed two linear dynamic ranges of 0.02 – 0.1 μM and 0.1-10 μM with a detection limit of 6 nM for the... 

This research is divided in three parts. In the first part of this research, we report the one-pot synthesis of carbonate-coated nanostructured LLO (Li2CO3@LLO) through a polyol-assisted method as a Li-ion battery cathode. Carbonate protects the cathode from adverse reactions with the electrolyte, also reduces the layered-to-spinel phase transition, thereby stabilizing the cathode structure. LLO nanostructure provides a fast Li+ diffusion. The target material exhibits excellent long-term stability with 77% capacity retention after 1000 cycles at 0.2C-rate. In the second part of research, Li(Na-doped)-Mn-Ni-O oxides were synthesized by different LiOH.H2O amount, type and amount of reducing... 

A novel amperometric non-enzymatic glucose (NEG) sensor is designed by a facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3- disulfonate as an anion dopant. The electrochemical performance of the modified electrode toward glucose detection is investigated by various electrochemical methods. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the surface of PPy@Cu(OH)2NTs electrode... 

In the recent years, conductive polymers are widely used in the design and construction of chemical and biological sensors.The polypyrrole due to features such as good thermal and chemical stability, ease of synthesis and better conductivity than other conductive polymers, atracts much attention. In order to modification of electrode surface,adhesiveand thin polymer films can be electropolymerized in the presence of organic or inorganic dopants on the surface of metal or carbon surfaces in aqueous or organic solutions. On the other hand carbon nanotubes by owing unique properties such as chemical stability and high electrical conductivity are good choice for electrod surface modification.... 

Chlorinated benzenes are a group of cyclic aromatic compounds which are used mainly as intermediates in the synthesis of pesticides and other chemicals. These compounds have harmful effects on human health, as on blood, kidneys, skin and eyes, and cause biological disorders and cancers. Chlorobenzenes have been ranked as priority pollutants by the US Environmental Protection Agency (EPA). The permissible level of these compounds for drinking water ranges between 2 μg/L and 1 mg/L. Hence determination of these compounds is of a significant importance. Solid Phase Dynamic Extraction (SPDE) of 5 types of chlorobenzenes (monochlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene,... 

In the first part, preparation of different kinds of polypyrrole/carbon composites and their application for drug analysis are described. In the first work, A very sensitive electrochemical sensor constructed from a glassy carbon electrode modified with a layer-by-layer MWCNT/doped overoxidized polypyrrole (oppy/MWCNT /GCE) was used for the determination of acetaminophen (AC) in the presence of codeine and ascorbic acid (AA). In comparison to the bare glassy carbon electrode, a considerable shift in the peak potential together with an increase in the peak current was observed for AC on the surface of oppy/MWCNT/GCE, which can be related to the enlarged microscopic surface area of the... 

In the first part, the electropolymerization of pyrrole was performed in the presence of Titan Yellow (TY) as a dopant anion on the surface of the electrode precoated with CNTs. The modified electrode was used to study the voltammetric response of tizanidine (TIZ). A remarkable increase was observed in the anodic peak current of TIZ on the surface of the modified electrode relative to the bare GCE. The surface morphology PPY/CNT/GCE was thoroughly characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques. Under the optimized analysis conditions, the modified electrode showed two linear dynamic ranges of 0.01 - 1 μM and 1-10 μM with a detection limit of 3 nM... 

This research is a bout a novel sample prepration procedure that used polypyrrole film into a stainless steel needle as a fiber coating for solid phase dynamic extraction(SPDE) with using a home-made SPDE devise and gas chromatography – mass spectroscopy for the extraction and detectionof Atrazine from the aqueous sample in direct mode of SPDE. Polypyrrole film was directly electrodeposited into the needle in a aqueous sodium dodecyl sulfonate solution with pecial set up in optimom condition of potential, time and concentration of polypyrrole. To enhance the sensitivity of the SPDE , variables affecting adsorption and desorption steps such as temperature,time,PH, flowrate and ionic strength... 

Porosity and high surface area is a profound concept for creating advance materials. Nanofibers are an important class of nano materials which would be used as novel sorbents because of their high surface to volume ratio as a result of long lengths and nano-to-micro-scale diameters. Electrospining is a simple method for producing fine nanofibers from different meterials such as, polymers, composites and ceramics to prepare highly efficient sorbents. Moreover, electrospining has been developed for fabricating nanofibers with core-shell structures. These structures in compared with conventional fibers have gained higher attentions due to their high aspect ratios and flexiblity in surface... 

Phenolic compounds, which are one of the most dangerous compounds for the environment, are present in many effluents of various industries such as petrochemicals and pharmaceuticals, and the need to eliminate these compounds is increasingly felt. In this study, adsorption of three compounds of para-chlorophenol, para-nitrophenol and hydroquinone on polypyrrole adsorbent in the form of neutral, charged, copolymer with polyaniline and phosphorus-doped have been investigated using density functional theory (DFT). Calculations are performed at two levels of b3lyp/6-31+G(d,p) and wb97xd/631+G(d,p) for two different orientations of adsorbate molecules that the correlation-exchange function wb97xd... 

Novel Copper Oxide microflowers /Polypyrroles nanowire nanocomposites with various wight ratio have been synthesized.The synthesized CuO/Ppy NCs and Cuo microflowers are characterized by XRD, FT-IR, TGA, FESEM and EDX line analysis/elemntal mapping. The formation mechanism of CuO microflower and Ppy nanowires are also well explained.All syntesized samples have been used as as anode material for li-ion batteries in order to measure their electochemical lithium-ion storage properties. It is demonstrated that presence of Ppy nanowire with different weight ratio plays important role in lithium-storage properties of the hybrid CuO/Ppy NCs. With increase in the mass ratio of Ppy nanowire cyclic... 

There are high attractions in the development of conducting polymer (CP) coatings to improve the electrochemical properties and biocompatibility of electrodes in the area of biosensors. In the first part of this thesis, a new type of modified electrodes, constructing multi-walled carbon nanotubes (MWCNTs) and polypyrrole is prepared in a layer-by-layer process. In this procedure, the glassy carbon electrode is casted first by a drop suspension of MWCNTs, leading to formation a thin film on its surface. In the second step, electrochemical polymerization of pyrrole in the presence of tiron (used as doping anion) is performed on the surface of the MWCNTs pre-coated electrode. The modification...