Chemistry Commons^™

Design, Synthesis, Characterization, And Applications Of Matrix Free Polymer Nanocomposites, Yucheng Huang

Theses and Dissertations

This dissertation focuses on the design, synthesis, characterization and application of matrix free polymer nanocomposites. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize block copolymers and polymer grafted silica nanoparticles with precise control over architectures.

In the first chapter, thermoplastic elastomer (TPE) grafted nanoparticles were prepared by grafting block copolymer poly(styrene-block-(n-butyl acrylate)) onto silica nanoparticles (NPs) (~15nm) via surface initiated RAFT polymerization. The effects of polymer chain length and graft density on the mechanical properties were investigated using films made solely from the grafted NPs. The ultimate tensile stress and elastic modulus increased with the increase of PS …

Synthesis And Reactivity Of Carborane Backbone Pincer Complexes, Bennett J. Eleazer

Theses and Dissertations

In organometallic chemistry, boron-centered ligand systems represent a powerful synthetic strategy for the promotion of a variety of catalytic transformations. These ligands offer a versatile array of bonding motifs, which can function as borane, boratrane, boryl, borate, or borylenes type ligands, and are likely the strongest σ-donors in the anionic series of ligands based on boron, carbon, nitrogen, and oxygen. Carboranes, which are icosahedral boron clusters of the type C2B10H12, offer unique potential as metal ligands, such as their bonding to exohedral metal centers being dominated by two-center-two-electron σ-bond interactions, their three-dimensional cluster structure providing considerable steric shielding to a …

Designed Polymer Brush Interfaces For Plutonium Separations And Polyethylene Nanocomposites, Julia G. Pribyl

Theses and Dissertations

Modification of surfaces with polymer brushes has become an important area of research for developing materials with a variety of advanced properties. Flat or continuous surfaces modified with polymer brushes can serve as surfaces where chemical reactions or separations take place, and discrete nanoparticles covered in a polymer brush can disperse within a miscible surrounding polymer, generating a composite which retains the processability of the polymer but becomes endowed with the properties of the filler as well. Presented herein are new synthetic approaches to modify both continuous surfaces as well as discrete particles with polymer brushes for complex applications. In …

Synthesis And Characterization Of Polydiene-Grafted Nanoparticles, Zaid Mohammed Abbas Alajeeli

Theses and Dissertations

This dissertation presents the design, synthesis, and characterization of polydiene grafted nanoparticles as a way to tailor nanocomposite interfaces and properties via interface design. The polymerization of dienes was done via reversible addition fragmentation chain transfer (RAFT) polymerization. The grafting of polymer chains on the surface of silica nanoparticles can be controlled through the molecular design of the RAFT agents attached to the nanoparticles surface. The properties of the nanocomposites largely depended on the interface between the particles and the polymer matrix. In the first part of this work, the polymerization of diene monomers was done on 15 nm diameter …

Development Of A High-Resolution Spatial Heterodyne Libs Spectrometer, Kevin A. Dudley

Theses and Dissertations

Laser-Induced Breakdown Spectroscopy (LIBS) is an atomic emission technique that uses a pulse laser to ablate a sample and form a plasma. Atomic emissions from the plasma provide unique elemental characteristics regarding the composition of the sample. The technique produces valuable qualitative results, but the accuracy of quantitative analyses is hindered by spectral line broadening mechanisms and laser pulse reproducibility, among other factors. The Spatial Heterodyne Spectrometer (SHS) is a high-resolution spectrometer with very high light throughput, and its use to LIBS is currently limited to two peer-reviewed publications. In the following work a high resolution SHS is developed and …

Mechanistic Investigations Of The Iron(Iii)-Catalyzed Carbonyl-Olefin Metathesis Reaction, Susan Phan

Master's Theses

Iron(III)-catalyzed carbonyl-olefin ring-closing metathesis represents a new approach toward the assembly of molecules traditionally generated by olefinˆ’olefin metathesis or olefination. Herein, we report detailed synthetic, spectroscopic, kinetic, and computational studies to determine the mechanistic features imparted by iron(III), substrate, and temperature to the catalytic cycle. These data are consistent with an iron(III)-mediated asynchronous, concerted [2+2]-cycloaddition to form an intermediate oxetane as the turnover-limiting step. Fragmentation of the oxetane via Lewis acid-activation results in the formation of five- and six-membered unsaturated carbocycles.

Strength Of Π-Stacking, From Neutral To Cation: Precision Measurement Of Binding Energies In An Isolated Π-Stacked Dimer, Damian Kokkin, Maxim V. Ivanov, John Loman, Jin-Zhe Cai, Rajendra Rathore, Scott A. Reid

Chemistry Faculty Research and Publications

π-Stacking interactions are ubiquitious across chemistry and biochemistry, impacting areas from organic materials and photovoltaics to biochemistry and DNA. However, experimental data is lacking regarding the strength of π-stacking forces—an issue not settled even for the simplest model system, the isolated benzene dimer. Here, we use two-color appearance potential measurements to determine the binding energies of the isolated, π-stacked dimer of fluorene (C₁₃H₁₀) in ground, excited, and ionic states. Our measurements provide the first precise values for π-stacking interaction energies in these states, which are key benchmarks for theory. Indeed, theoretical predictions using ab initio and …

Determination Of Organic Acid Preservatives In Shrimp Paste By Headspace Solid-Phase Microextraction Combined With Gas Chromatography, Nuttanee Tungkijanansin

Chulalongkorn University Theses and Dissertations (Chula ETD)

Organic acids, which are benzoic acid, sorbic acid and propionic acid, are the most common preservatives used in foods and have been regulated the usage. Shrimp paste, called Kapi in Thai, is a fermented food that used in many Thai dishes. Owing to a complex matrix in shrimp paste, sample preparation is required to determine the amount of organic acid preservatives in shrimp paste. In this work, headspace solid-phase microextraction (HS-SPME) was developed for extraction of organic acid preservatives in shrimp pastes and analyzed by gas chromatography with flame ionization detector (GC-FID). The 85 µm polyacrylate coated fiber was used …

Paper-Based Analytical Device For Determination Of Triglycerides, Yolthida Kantapa

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, a paper-based analytical device (PAD) together with enzymatic reactions was developed for determination of triglycerides using colorimetric detection. The method was based on the enzymatic reactions between triglycerides and enzymes (lipase, glycerol kinase and glycerol-3-phosphate oxidase). Hydrogen peroxide which was generated from the enzymatic reactions is reduced by chromogenic substrates which were 3-methyl-2-benzothiazolinone hydrazone (MBTH) and 3-(dimethylamino)benzoic acid (DMAB) in the presence of peroxidase to produce an indamine dye. The blue color intensity of indamine dye is directly proportional to triglycerides concentration. For quantitative analysis, the interfering effect of ascorbic acid in real samples was eliminated using …

Positively Charged Particles From Amphiphilic Chitosan For Plasmid Dna Delivery, Tinnakorn Phuangkaew

Chulalongkorn University Theses and Dissertations (Chula ETD)

Amphiphilic chitosan derivatives have been well regarded as potential non-viral vectors for gene delivery. Their hydrophobic entities could promote cell permeability whereas their hydrophilic entities especially those carrying positive charges can interact with the negatively charged phosphate groups of DNA. Here in this research, a series of amphiphilic chitosan derivatives were synthesized. Linear hydrocarbon of two different chain length: hexyl (C6) and dodecyl (C12) were substituted at amino groups of chitosan via reductive alkylation with hexanal and dodecanal and yielded two hydrophobized chitosan derivatiives, hexyl chitosan (HCS) and dodecyl chitosan (DCS), respectively. Phthaloyl chitosan (PhCS) was also prepared as another …

Reduced Graphene Oxide-Modified Screen-Printed Carbon Electrode For Determination Of Homocysteine Using Catechol, Suchapa Naranaruemol

Chulalongkorn University Theses and Dissertations (Chula ETD)

Homocysteine (Hcy), also known as 2-amino-4-mercaptobutyric acid, is a biomarker that is directly associated with an increased risk of cardiovascular diseases (CVDs). In this work, catechol (CA), which is redox active, had been used as an electron transfer mediator to facilitate the oxidation of Hcy. Typically, CA was first electrochemically immobilized onto the surface of screen-printed carbon electrode; however, the obtained CA-functionalized electrode did not show the electrocatalytic activity towards the detection of Hcy. Therefore, the deter– mination of Hcy was investigated in the solution containing CA using differential pulse voltammetry (DPV) at the reduced graphene oxide-modified screen-printed carbon electrode …

Modification Of Screen-Printed Carbon Electrode With Mxene/Conductive Polymer Composites For Hydrogen Peroxide Detection, Supawat Neampet

Chulalongkorn University Theses and Dissertations (Chula ETD)

MXene (Ti3C2), a two-dimensional material consisting of transition metal carbides, nitrides or carbonitrides was prepared by etching method for modification electrode of a novel nanocomposites consisting of platinum nanoparticles (PtNPs) and polyaniline (PANI) via electrodeposition and electropolymerization, respectively. The fabricated MXene/PANI/PtNPs nanocomposite modified on surface screen-printed carbon electrode (SPCE) were characterized by scanning electron microscopy SEM) with energy dispersive X-rays spectroscopy (EDX), X-ray powder diffraction (XRD), and transmission electron microscopy (TEM) to verify the presence of nanocomposite materials and indicate their morphologies. This electrode was applied for the detection of hydrogen peroxide (H2O2), which is a common electroactive product from …

Synthesis And Biological Activities Of Halogenated Chalcone-Based Pyra, Dinh Phuoc Nguyen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Twenty new 1,3,5-trisubstituted pyrazoline derivatives have been synthesized from chalcones and acylhydrazides in two steps. In the first step, chalcones were prepared by treatment of various acetophenones with different substituted benzaldehydes by Claisen-Schmidt condensation. In the second step, pyrazoline derivatives were synthesized by conducting the reaction of chalcones with acylhydrazides in acetonitrile at 67 °C in the presence of triazabicyclodecene as a catalyst. The synthesized compounds were identified by 1H, 13C NMR and HRMS spectral data and were evaluated for their antibacterial, anticancer and tyrosinase inhibitory activities. In antibacterial and tyrosinase inhibitory activities, most of pyrazoline derivatives showed inactive properties. …

ผลของสารลดแรงตึงผิวต่อการเตรียมตัวเร่งปฏิกิริยา Ptco/C สําหรับปฏิกิริยารีดักชันของออกซิเจน ในเซลล์เชื้อเพลิงพีอีเอ็ม, ปาณิศา ปราบ ณ ศักดิ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาผลของสารลดแรงตึงผิวที่มีต่อตัวเร่งปฏิกิริยา PtCo/C สำหรับปฏิกิริยารีดักชันของออกซิเจนในเซลล์เชื้อเพลิงพีอีเอ็ม ซึ่งสารลดแรงตึงผิวที่ใช้ในการทดลองประกอบด้วย สารลดแรงตึงผิวชนิดประจุบวก (CTAB), ชนิดประจุลบ (SDS), และชนิดไม่มีประจุ (Triton X-100) โดยทำการเตรียมตัวเร่งปฏิกิริยา PtCo/C ร้อยละ 20 โดยน้ำหนัก ผลการทดลองพบว่าตัวเร่งปฏิกิริยาที่ใช้ CTAB ความเข้มข้น 0.004 โมลต่อลิตร ให้พื้นที่ผิวในการเกิดปฏิกิริยาเคมีไฟฟ้าสูงที่สุด นอกจากนี้การปรับปรุงตัวเร่งปฏิกิริยาด้วยความร้อนที่อุณหภูมิ 600 องศาเซลเซียส สามารถเพิ่มพื้นที่ผิวในการเกิดปฏิกิริยาและช่วยลดขนาดอนุภาคของตัวเร่งปฏิกิริยาลงได้ เนื่องจากการปรับปรุงด้วยความร้อนจะกำจัดสารลดแรงตึงผิวที่บดบังบริเวณการเกิดปฏิกิริยา การศึกษาเสถียรภาพของตัวเร่งปฏิกิริยาในสารละลายกรดซัลฟิวริกที่อิ่มตัวด้วยไนโตรเจน ความเข้มข้น 0.5 โมลต่อลิตร พบว่า CTAB ความเข้มข้น 0.004 โมลต่อลิตร มีเสถียรภาพสูงที่สุด รองลงมาเป็น Triton X-100 และ SDS ตามลำดับ ซึ่งเป็นผลมาจากปริมาณพื้นที่ผิวในการเกิดปฏิกิริยาของตัวเร่งปฏิกิริยา ส่วนของการทดสอบกัมมันตภาพสำหรับปฏิกิริยารีดักชันของออกซิเจนในสารละลายกรดที่อิ่มตัวด้วยออกซิเจนและเซลล์เชื้อเพลิงพีอีเอ็มแบบเซลล์เดี่ยวภายใต้ภาวะไฮโดรเจน/ออกซิเจน ที่อุณหภูมิ 60 องศาเซลเซียส ความดันบรรยากาศ พบว่า Triton X-100 ความเข้มข้น 0.001 โมลต่อลิตร ให้กัมมันตภาพในสารละลายกรดและเซลล์เชื้อเพลิงพีอีเอ็มแบบเซลล์เดี่ยวสูงที่สุด

Phenolic Resin Aerogels: The Significance Of Inserting An Oxidative Ring-Fusion Aromatization Step At The Early Stages Of Pyrolytic Carbonization, And The Application Of These Materials In Co₂ Storage And Separation, Hojat Majedi Far

Doctoral Dissertations

"Phenolic aerogels, prepared via polycondensation of phenolic monomers and formaldehyde, were converted to carbon aerogels at 800 ⁰C/Ar followed by reactive etching under flowing CO₂. Previously, it was found that a lower-temperature air-oxidation of polybenzoxazine aerogels was necessary in order to obtain highly porous, isomorphic carbon aerogels with high carbonization yields. Using those findings as the point of departure, phenolic aerogels were oxidized at 240 ⁰C/air prior to carbonization. During that air-oxidation step, phenolic aerogels based on phloroglucinol (1,3,5- trihydroxybenzene) undergo fusion of their aromatic rings, yielding 6-membered heteroaromatic pyryliums with pendant phenoxide ions. The resulting carbon aerogels …

Carbon Dioxide Capture On Nitrogen-Doped Carbon Nanoparticle Derived From Aromatic Compounds Via Solution Plasma And Nitridation, Phuwadej Pornaroontham

Chulalongkorn University Theses and Dissertations (Chula ETD)

The carbon dioxide (CO2) adsorption on nanocarbon (C), oxygen-doped nanocarbon synthesized from benzene and a mixture of benzene and metal working fluid (MWF), respectively, via solution plasma process (SPP) have been revealed in this study. Firstly, they showed low CO2 adsorption capacity at 25 °C. However, their capacities were enhanced by nitridation under ammonia atmosphere at high temperature. The maximum CO2 adsorption capacity of 1.63 mmol g-1 was achieved on nitrogen-oxygen-codoped nanocarbon obtained from SPP discharging a mixture containing 15 vol% MWF nitrided at 800 °C (noC15(800)). The characterizations revealed that the micropososity and nitrogen functionality on the adsorbent are …

Computational Fluid Dynamics Of Fluid Transport And Deposition Of Particles Under Unsteady Flow In Human Fluid System, Ratchanon Piemjaiswang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Computational fluid dynamics has been widely used to investigate flow phenomena in many different applications. This study focuses on the development of computational fluid dynamic model in biomedical applications, including the flow within human respiratory system and the flow within human circulating system. For the model of respiratory system, electrostatic charge model was coupled, and the effect of breathing frequency was investigated. The accomplishment of the study will gain better understanding of the hydrodynamics when applying the electrostatic field, and will use to identify the potential aerosol deposition location. The aerosol properties and morphologies were also considered their effect on …

Development Of Optical Sensor For Detection Of Chloride Ions And Electrochemical Sensor For Detection Of Clinical Indicators, Abdulhadee Yakoh

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation concentrated on the development of nanomaterials-based miniaturized platforms for the detection of some important compounds/indicators from environmental, pharmaceutical, and clinical application. This dissertation can be classified into two main parts: (1) development of nanomaterials-based miniaturized platforms for optical sensing application, and (2) development of nanomaterials-based miniaturized platforms for electrochemical sensing applications. In the first part, two sub-sections were discussed. For the first sub-section, the paper-based colorimetric sensor for chloride ion determination using silver nanoprisms was developed. Using a smartphone as an optical readout, the color change from the oxidative etching of the silver nanoprisms to the silver nanospheres …

Development Of Sr₂Fetio[₆-Delta] Electrode For Solid Oxide Fuel Cell, Ausa Potong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Sr₂FeTi₁-x(Nb,V)xO₆ (x=0.05-0.50) double perovskites have been synthesized by the substitution of Nb and V on Ti sites of Sr₂FeTiO₆ (SFT) and tested as electrode for intermediate temperature solid oxide fuel cell (IT-SOFC). The XRD analyses indicated Sr₂FeTi₀.₉₅Nb₀.₀₅O₆ and Sr₂FeTi₀.₉₅V₀.₀₅O₆ were pure and the impurities, Sr(FeNb) ₀.₅O₃ and Sr3(VO4) ₂, were found with the increasing of Nb and V contents in SFT. By small addition of Nb and V in SFT, the electrical conductivity and electrochemical property of SFT was improved. Among the various oxide examined, Sr₂FeTi₀.₉₅Nb₀.₀₅O₆ and Sr₂FeTi₀.₉₅V₀.₀₅O₆ showed the highest electrical conductivity of 2.44 and 3.93 S cm⁻¹, respectively, …

Carbon Sorbent Reinforced Hollow Fiber Membrane Microextraction For Determination Of Trace Polar Organic Compounds, Chanatda Worawit

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work presents a proof of concept that hollow fiber liquid phase microextraction reinforced with carbon nanomaterials would improve the extraction efficiency of small and relatively polar organic compounds. Several types of carbon sorbents such as graphite, graphene, carbon nanofiber were studied. In research I, the hollow fiber membrane reinforced with graphite was developed for liquid phase microextraction of trihalomethanes in water samples. Parameters affecting extraction efficiency including organic solvent as supported liquid membrane, amount of loaded graphite and extraction time were investigated and optimized. The working range of 0.2-120 µg L-1 was obtained in 10 min extraction with good …

Development Of Electrochemical And Colorimetric Methods Using Inorganic Nanomaterials For Detection Of Biological And Environmental Compounds, Chanika Pinyorospathum

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research comprised of 2 parts including (1) lab-on-paper coupled with electrochemical method for C-reactive protein and colorimetric detection for phosphate ions and (2) the development of chromatographic techniques and its applications. In each part, it can be classified in 2 works. The first work of lab-on-paper is the electrochemical sensor that was fabricated from phosphorylcholine assembled electrodeposited gold nanoparticles onto screen-printed carbon electrode for C-reactive protein detection. Current of ferrocyanide decrease linearly when increase C-reactive protein concentration from 5.0 – 5000 µg L⁻¹. The calculated detection limit equals 1.60 µg L⁻¹. The final part of lab-on-paper is the colorimetry …

Study Of Substitution Reaction On Ring A Of Estradiol, Chanoknun Boonyaratsewee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Estradiol-conjugated anticancer drugs are the effective strategy that could specifically combat breast cancer cells, while minimizing the toxicity of the drug toward normal cells. Estradiol has been previously conjugated with drugs mostly at rings B, C and D. Functionalizations at ring A of estradiol introduce new types of conjugated drugs that could improve both the selectivity and efficiency in binding with estrogen receptor (ER). Using 4-cresol as the model, the nitration at meta-position was achieved, although with unsatisfied result of only 6% overall yield of the product. The practical results derived from diazo coupling on ortho-position of 4-cresol, which led …

Molecularly Imprinted Polymer Modified Optical Fiber Sensor Based On Surface Plasmon Resonance Spectroscopy For Determination Of Atrazine, Chidchanok Tabtimhin

Chulalongkorn University Theses and Dissertations (Chula ETD)

A sensitive sensor device based on surface plasmon resonance (SPR) spectroscopy was developed on an optical fiber and made to be selective to atrazine by molecularly imprinted polymer. The SPR probe was fabricated by deposition of gold nanoparticles on the uncladed surface of an optical fiber by self-assembly method. The size and distribution of gold nanoparticle was optimized by varying the soaking time of the optical fiber. The surface was further modified for selective sensing of atrazine with the molecularly imprinted polymer (MIP). The MIP was synthesized via 2 methods, the first was thermal polymerization method, the MIP was then …

Enzymatic Reaction Based Biosensor For Specific Detection Of Organophosphate Pesticides, Chonticha Sahub

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aims to design and develop two-biosensor platforms based on graphene quantum dots (GQDs) via enzymatic reaction for determining organophosphate pesticides (OPs). A first platform consisting of GQDs and active enzyme, GQDs/Enz platform, is simply fabricated in aqueous solution. Ongoing development of GQDs/Enz platform for effective OPs sensing by hybrid hydrogel (GQDs/Enz/Gels) was of great interest to improve the sensitivity and enzyme stability under the benefit of easy to be used for sensing approach. The GQDs/Enz and GQDs/Enz/Gels were constructed and characterized by general methods such as FT-IR, SEM and TEM. Based on the concept, H2O2 generated in situ …

Adsorption Of Tetrachloroaluminate Ion On Graphene Quantum Dots, Fadjar Mulya

Chulalongkorn University Theses and Dissertations (Chula ETD)

The important thing in the mechanism of aluminium ion battery is the fast adsorption of tetrachloroaluminate [AlCl4]- on intercalation sites of bulk graphite which can increase the efficiency and lifetime of the battery. In this study, we modeled graphene quantum dots (GQDs) as cathode material. For the adsorption of [AlCl4]-, coronene (C24H12) and circumcoronene (C54H18) were used as the model of GQDs with three types of adsorption sites and standing positions. The charge of GQDs was modified to be 0 and +1 to address discharging and charging conditions. The distance between chlorine atom and carbon atom of GQDs was found …

Green Synthesis Of Guanidines Directly From Thiourea, Jakkrit Srisa

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this work, one-pot synthesis of guanidines directly from isothiocyanates using DIB (diacetoxyiodobenzene) as a desulfurizing agent under a micellar condition in water was developed. The optimization study revealed that the use of 1wt%TPGS-750-M as a surfactant with NaOH as a base at room temperature can convert aromatic isothiocyanates and varieties of amines into the corresponding guanidines in good to excellent yields (69 - 95%). This green synthetic process in water can be applied to prepare guanidine at gram-scale quantity. The aqueous micellar medium was also reusable to give relatively the similar reaction yields for at least three cycles. The …

Application Of Capillary Electrophoresis For Determination Of Glycosaminoglycans In Biological And Cosmetic Samples, Kanokporn Chindaphan

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this research, on-line preconcentration and determination of glycosaminoglycans (GAGs), especially chondroitin sulfate (CS), dermatan sulfate (DS) and hyaluronic acid (HA) using capillary electrophoresis (CE) was developed. Large-volume sample stacking using an electroosmotic flow (EOF) pump (LVSEP) technique was employed for on-line preconcentration and improvement of the detection sensitivity in CE method. Central composite design (CCD) was used to simultaneously optimize all parameters for CE separation. The optimized CE conditions were background electrolyte consisting of 200 mM sodium dihydrogen phosphate, 200 mM buthylamine and 0.5% w/v polyethylene glycol at pH 4.0 and separation voltage of -16 kV. Limit of detections …

Electrochemical Detection Of Herbicides And Antioxidants Using Nanomaterial-Modified Electrode, Kanokwan Charoenkitamorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation focused on the development of a novel nanomaterial-based electrochemical sensors for pharmaceutical and environmental applications. The research is divided into two parts. In the first part, a low-cost and disposable sensor for the simultaneous determination of coenzyme Q10 (CoQ10) and α-lipoic acid (ALA) using manganese (IV) oxide-modified screen-printed graphene (MnO2/SPGE) electrode was developed. The incorporated MnO2 in the SPGE can greatly enhance the detection performance towards the oxidation of CoQ10 and ALA. The cyclic voltammetry (CV) and square-wave anodic stripping voltammetry (SWASV) were employed to investigate the electrochemical behavior of the developed sensor and also to perform the …

Dft And Dftb Investigations On Α–Mangostin Dye Adsorbed On Titanium Dioxide Electrode In Dsscs Application, Kanthira Kaewsud

Chulalongkorn University Theses and Dissertations (Chula ETD)

Conformations of α–mangostin dye (1,3,6–Trihydroxy–7–methoxy–2,8–bis(3–methyl–2–buten–1–yl)–9H–xanthen–9–one) were studied and three conformers were found as three co-existing species in various media (in vacuo, acetonitrile and water). Geometries, electronic structures and UV–Vis spectra of all conformers in various media have been obtained using density functional theory (DFT) and time–dependent DFT (TD–DFT) methods. The conformers of α–mangostin dye were inspected as photosensitizers for application in dye sensitized solar cells (DSSCs) and their light–harvesting efficiencies (LHEs) within the range of 0.6757–0.7556 eV (in vacuo), 0.8286–0.8466 eV (in acetonitrile) and 0.8288–0.8465 eV (in water) were obtained. The open circuit voltage (VOC) of three conformers within the …

Speciation Of Arsenic Using Sulfur Containing Ligand And Cotton Wool By Icp-Oes, Kavee Triteeyaprasert

Chulalongkorn University Theses and Dissertations (Chula ETD)

This research aimed to develop a method for speciation of arsenic species including As(III) and As(V) in environmental samples. Cotton wool and sulfur containing ligands including ammonium pyrrolidinedithiocarbarmate (APDC), L–cysteine and diethyldithiocarbamic acid were used in a solid phase extraction and determination of arsenic by using inductively coupled plasma optical emission spectrometry. The separation parameters were studied including pH, ligand concentration, cotton amount, type of eluents and flow rate. It was found that at pH 2, 0.1% APDC concentration and 0.5 g of cotton, As(III) could form complex with APDC (As(III) – APDC) and was separated from As(V) by using …