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Articles 5851 - 5880 of 33152
Full-Text Articles in Chemistry
Development Of A New Spe Uplc–Ms/Ms Method For Extraction And Quantitation Of Toluene Diamine On Gloves Following Toluene Diisocyanate Exposure, Asma Daoud, Pierre-Luc Cloutier, Sébastien Gagné, Livain Breau, Jacques Lesage
Development Of A New Spe Uplc–Ms/Ms Method For Extraction And Quantitation Of Toluene Diamine On Gloves Following Toluene Diisocyanate Exposure, Asma Daoud, Pierre-Luc Cloutier, Sébastien Gagné, Livain Breau, Jacques Lesage
Études primaires
Rationale
Toluene diisocyanate (TDI) is a highly reactive isocyanate commonly used as a mixture of 2,4- and 2,6- isomers in the production of flexible foams. Exposure to TDI occurs primarily through vapour inhalation in workplaces where TDI is produced or used, but dermal exposure is also possible during some tasks. To ensure workplace safety, accurate monitoring of TDI and toluene diamine (TDA) levels is required. Methods of quantifying field effectiveness of gloves in preventing dermal exposure have not been established. Therefore, there is a need to develop a new practical method for assessing glove effectiveness for TDI/TDA.
Method
A new …
Molecular Engineering Of Self-Immolative Polymers As Chemically Responsive Temporary Adhesives For Protective Garments, Hana J. Yarbrough
Molecular Engineering Of Self-Immolative Polymers As Chemically Responsive Temporary Adhesives For Protective Garments, Hana J. Yarbrough
Dartmouth College Master’s Theses
The long-term goal of this thesis is to design novel chemical protective garments that both shield and sense for chemical warfare agents. The overarching hypothesis of this work is that joining textiles with a chemically responsive temporary adhesive will reduce the permeability of and detect hazardous analytes across fabric boundaries. Work towards achieving this goal and testing this hypothesis is separated into two chapters. The first chapter reports the development of a self-immolative polymer, poly(phthalaldehyde), into a stimuli-responsive temporary adhesive. Developing poly(phthalaldehyde) as a robust adhesive that rapidly releases substrates would be a significant and novel contribution to the fields …
Development Of A Chromatographic Method To Authenticate Aspirin Brands, Megan Guetzloff
Development Of A Chromatographic Method To Authenticate Aspirin Brands, Megan Guetzloff
Electronic Theses and Dissertations
Counterfeit pharmaceuticals pose a threat to society that can include inaccurate amounts of the active pharmaceutical ingredient (API), no API, or containing off-target compounds. For example, there are many recent examples of counterfeit pharmaceuticals containing potentially lethal doses (> 2 mg) of fentanyl (i.e., a synthetic opioid). Current measures to combat illicit pharmaceuticals (e.g., unique packaging and product serialization) have merit, however with evolved technologies, counterfeiters can relatively easily simulate these measures and continue to distribute illicit pharmaceuticals. The only accurate way to definitively determine that a suspected counterfeit is, in fact, counterfeit is advanced chemical analysis. However, current methods …
Formulation, Structure, And Applications Of Therapeutic, Amino Acid, And Water-Based Deep Eutectic Solvents, Md Sajjadur Rahman
Formulation, Structure, And Applications Of Therapeutic, Amino Acid, And Water-Based Deep Eutectic Solvents, Md Sajjadur Rahman
Electronic Theses and Dissertations
In the design of greener chemicals, deep eutectic solvents (DESs) are considered as one of the most versatile alternative solvents with widespread applications. DESs have the advantages of being nonflammable with negligible vapor pressure compared to traditional solvents. They share many characteristics of ionic liquids, but DESs are cheaper to formulate, typically nontoxic, recyclable, biodegradable, and are suitable for use with biological systems. In my Ph.D. research, three types of emerging and unconventional types of DESs, namely therapeutic DES (THEDES), amino acid-based DES (AADES), and water-based DES (WDES), have been investigated. To formulate these DES easily available and cheaper chemicals, …
Using Powder Diffraction To Give Insight Into Structures Of Ir2(Diisocyanomenthane)4x2 [Dimen] (X = Cl; Pf6; Bph4), Mairead Brownell
Using Powder Diffraction To Give Insight Into Structures Of Ir2(Diisocyanomenthane)4x2 [Dimen] (X = Cl; Pf6; Bph4), Mairead Brownell
Scripps Senior Theses
Ir2(dimen)42+ (dimen = 1,8-diisocyanomenthane) has been studied extensively as model compound to better understand catalysis of photochemical reactions. Although Ir2(dimen)42+ has been used primarily to observe the photophysical changes of metal-metal transitions, it gives great insight into the transitions that allow other d8-d8 metal complexes to undergo photochemical processes and generate hydrogen gas. The large visible range by which Ir2(dimen)42+ (1) can be electronically excited in solution is indicative of its two solution phase ground states, which interestingly have been hypothesized to resemble two unique packing structures observed in the powder state. In this study, the powder diffraction patterns of …
Reinforcement Of Elastomers By Reactive Ionic Surfactant, Nicole Vickerman
Reinforcement Of Elastomers By Reactive Ionic Surfactant, Nicole Vickerman
Williams Honors College, Honors Research Projects
Elastomers without cross-linking agents or fillers do not have the necessary properties for practical applications in the rubber industry. Elastomers must be reinforced with fillers and/or cross-linking agents to achieve the needs of physical and mechanical properties for commercial products. Sodium octyl 6-mercaptohexyl phosphate (SOMP) and sodium ethyl (6-mercaptohexyl) phosphate (SEMP) were used to investigate the influence of a reactive ionic surfactant and its influence on the physical properties of peroxide crosslinked styrene butadiene rubber (SBR). SEMP and SOMP were both found to be able to be grafted successfully on to the SBR chains within the rubber using extraction testing …
Understanding And Harnessing The Structural Features That Govern Hmg-Coa Reductase Activity, Edwin Ragwan
Understanding And Harnessing The Structural Features That Govern Hmg-Coa Reductase Activity, Edwin Ragwan
Bryn Mawr College Dissertations and Theses
The enzyme 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMGR), which catalyzes the reduction of HMG-CoA to mevalonate using two equivalents of the cofactor NAD(P)H, is part of the mevalonate pathway, found in all kingdoms of life. This pathway is at the heart of natural product biosynthesis constituting one of the obligate routes to producing the building blocks for isoprenoids, which represent the largest and most diverse class of natural products. Natural products and its derivatives continue to provide important compounds in the fields of drug development, biomedical engineering, and commercially-driven products. Therefore, HMGR, which performs the rate-limiting step of the mevalonate pathway garners …
First Long-Time Airborne Fungal Spores Study In Dublin, Ireland (1978–1980), Moisés Martínez-Bracero, Emma Markey, Jerry Hourihane Clancy, John Sodeau, David J. O'Connor
First Long-Time Airborne Fungal Spores Study In Dublin, Ireland (1978–1980), Moisés Martínez-Bracero, Emma Markey, Jerry Hourihane Clancy, John Sodeau, David J. O'Connor
Articles
Ambient fungal spores within the atmosphere can contribute to a range of negative human, animal and plant health conditions and diseases. However, trends in fungal spore seasonality, species prevalence, and geographical origin have been significantly understudied in Ireland. Previously unpublished data from the late 1970s have recently been collected and analysed to establish historical fungal spore trends/characteristics for Dublin. Historical spore concentrations were largely dominated by Alternaria, Ascospores, Basidiospores, Botrytis, Cladosporium, Erysiphe and Rusts. The main fungal spore season for Dublin commenced in April with the fructification of Scopulariopsis and Ganoderma. However, the vast majority of other spore types did …
Airborne Fungal Spore Review, New Advances And Automatisation, Moisés Martínez-Bracero, Emma Markey, Jerry Hourihane Clancy, Eoin Mcgillicuddy, Gavin Sewell, David J. O'Connor
Airborne Fungal Spore Review, New Advances And Automatisation, Moisés Martínez-Bracero, Emma Markey, Jerry Hourihane Clancy, Eoin Mcgillicuddy, Gavin Sewell, David J. O'Connor
Articles
Fungal spores make up a significant portion of Primary Biological Aerosol Particles (PBAPs) with large quantities of such particles noted in the air. Fungal particles are of interest because of their potential to affect the health of both plants and humans. They are omnipresent in the atmosphere year-round, with concentrations varying due to meteorological parameters and location. Equally, differences between indoor and outdoor fungal spore concentrations and dispersal play an important role in occupational health. This review attempts to summarise the different spore sampling methods, identify the most important spore types in terms of negative effects on crops and the …
Investigation Of Hazelnut Shells Driven Hard Carbons As Anode For Sodium-Ion Batteriesproduced By Hydrothermal Carbonization Method, Eli̇f Canbaz, Meral Aydin, Rezan Demi̇r Çakan
Investigation Of Hazelnut Shells Driven Hard Carbons As Anode For Sodium-Ion Batteriesproduced By Hydrothermal Carbonization Method, Eli̇f Canbaz, Meral Aydin, Rezan Demi̇r Çakan
Turkish Journal of Chemistry
To be used as Na-ion battery anodes, hard carbon electrodes are synthesized from biomass, explicitly hazelnut shell (HS): via hydrothermal carbonization (HTC) followed by further pyrolysis at different temperatures (500, 750, 1000 °C). Then, the resulting hazelnut shell-based hard carbons are investigated using various methods including Fourier-transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The effects of binders (PVdF, Na-alginate, CMC, and PAA) on electrochemical performance are determined. The obtained composite electrodes with different binders are tested in sodium half-cell configurations. A strong correlation is recognized between carbonization temperature and electrochemical performances and structural …
Comparison Of Volatile Chemical Components Of Cystoseira Crinita Duby By Hydrodistillation(Hd) And Solid-Phase Microextraction (Spme) Methods And Antimicrobialand Scolicidal Activities Of Essential Oil And Extracts, Tayyi̇be Beyza Yücel
Turkish Journal of Chemistry
This study aims to derive an essential oil from Cystoseira crinita Duby, analyze the chemical composition of the essential oil, discover the antimicrobial activities of the oil and the extracts, and investigate the scolicidal activities of the extracts. The volatile organic compounds of Cystoseira crinita Duby were determined by GC/MS-FID using both hydro-distillation (HD) and solid-phase microextraction (SPME) methods. As a result of the essential oil analysis, 97.14% of 17 compounds and 93.13% of 19 compounds were elucidated. The main compounds identified were hexanal (31.802%), n-hexadecanoic acid (12.654%), trans-β-ionone (9.118%), 2E-hexenal (15.955%), heptadecane (15.729%) and tetradecane (13.458%). In addition, hexane, …
New Bis-Isoxazole With Monoterpenic Skeleton: Regioselective Synthesis, Spectroscopicinvestigation, Electrochemical, And Density Functional Theory (Dft) Studies, Ali Oubella, Meryem Hrimla, Mouhi Eddine Hachim, Mourad Fawzi, Abdoullah Bimoussa, Lahoucine Bahsis, Aziz Boutouil, Aziz Auhmani, Abdelkhalek Riahi, My Youssef Ait Itto
New Bis-Isoxazole With Monoterpenic Skeleton: Regioselective Synthesis, Spectroscopicinvestigation, Electrochemical, And Density Functional Theory (Dft) Studies, Ali Oubella, Meryem Hrimla, Mouhi Eddine Hachim, Mourad Fawzi, Abdoullah Bimoussa, Lahoucine Bahsis, Aziz Boutouil, Aziz Auhmani, Abdelkhalek Riahi, My Youssef Ait Itto
Turkish Journal of Chemistry
A novel bis-isoxazole was synthesized from (R)-Carvone and p-methylbenzaldoxime, via two successive [3+2] cycloaddition reactions (32CA). The newly obtained bis-isoxazole has been fully characterized by HRMS and NMR spectroscopy. The HMBC experiment was performed to determine the stereo and the regioselectivity of the reaction. The electrochemical behavior of the studied compound, in oxidation and reduction processes, was examined using the cyclic voltammetry technique. In addition, the regioselectivity of the [3+2] cycloaddition reaction and the molecular structure of the title compound was performed by density functional theory (DFT). The HOMO and LUMO orbitals were investigated to determine the electronic properties of …
Determination Of Triacylglycerol And Fatty Acid Compositions Of Impatiens Seed Oils Using Reverse Phase High Performance Liquid Chromatography, Anh Van Nguyen, Anh Thi Ngoc Vu, Victor Ivanovic Deineka, Huy-Trung-Kien Nguyen
Determination Of Triacylglycerol And Fatty Acid Compositions Of Impatiens Seed Oils Using Reverse Phase High Performance Liquid Chromatography, Anh Van Nguyen, Anh Thi Ngoc Vu, Victor Ivanovic Deineka, Huy-Trung-Kien Nguyen
Turkish Journal of Chemistry
In the present work, triacylglycerol and fatty acid compositions of Impatiens balsamina L. and Impatiens walleriana Hook.f. seed oils were determined using reverse phase high performance liquid chromatography with both refractive index and spectrophotometric detections. The presence of conjugated octadecatetraenoic moieties was confirmed by UV and IR spectroscopy. Triacylglycerol (TAG) compositions were performed using an incremental approach and confirmed by the results of MS and electronic spectra. The quantitative analysis of TAG was achieved by careful calibration, introducing correction factors for the sensitivity of each compound. The results showed that both Impatiens seed oils contain the same 23 TAGs. The …
A New Electrochromic Copolymer Composed Of 4,7-Di(Thiophen-2-Yl)Benzo[C] [1,2,5] Thiadiazole And 3,4-Ethylenedioxythiophene, Kübra Çeli̇k, Ari̇f Kivrak, Buket Çarbaş
A New Electrochromic Copolymer Composed Of 4,7-Di(Thiophen-2-Yl)Benzo[C] [1,2,5] Thiadiazole And 3,4-Ethylenedioxythiophene, Kübra Çeli̇k, Ari̇f Kivrak, Buket Çarbaş
Turkish Journal of Chemistry
A new electrochromic copolymer based on 4,7-di(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole and 3,4-ethylenedioxythiophene was successfully obtained via the electrochemical polymerization method in the medium of electrolyte solution, which consists of 0.1 M tetrabutylammonium hexafluorophosphate and dichloromethane. In order to compare the electrochemical and chemical properties of the copolymer, the benzothiodiazole derivative and 3,4-ethylenedioxythiophene (EDOT) monomers, which are parts of the copolymer, are electrochemically polymerized, separately in the same environment and concentration with the copolymer. Poly(4,7-di(thiophen- 2-yl)benzo[c][1,2,5]thiadiazole) (P(TBT)) and poly(3,4-ethylenedioxythiophene) (PEDOT) polymers were obtained. Before starting the electrochemical synthesis, the initial oxidation potentials of the monomers that form the copolymer were compared via the …
Influence Of Acid Activation On Hydrogen Adsorption Properties Of Analcime-Rich Tuff From Turkey, Meryem Akbelen, Nurgül Özbay
Influence Of Acid Activation On Hydrogen Adsorption Properties Of Analcime-Rich Tuff From Turkey, Meryem Akbelen, Nurgül Özbay
Turkish Journal of Chemistry
In this study, structural, thermal, and hydrogen (H2) adsorption properties of natural analcime-rich zeolite tuff (A) from Trakya (Turkey) and that of acid-treated forms investigated. Analcime mineral was treated with 0.1, 0.5, 1, 2, and 3 M HCl solutions at 80 °C for 5 h. Differences in structural and thermal behaviors of the analcime samples before and after acid- treatment were examined by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy with detector x-ray energy dispersive (SEM-EDX), thermal analysis (TG-DTG-DTA) and nitrogen adsorption methods. Micropore volume, micropore area, and specific surface …
Insight Into Electrochemical Degradation Of Cartap (In Padan 95sp) By Boron-Doped Diamond Electrode: Kinetic And Effect Of Water Matrices, Hoang Nguyen
Turkish Journal of Chemistry
In this work, the kinetic electrochemical degradation of Cartap (CT) (in Padan 95 SP) at boron-doped diamond (BDD) electrode was investigated. This study indicated that the degradation of CT underwent both direct and indirect oxidations. Water matrices can either accelerate or inhibit the removal efficiency of CT: adding 15 mM Cl- improved kCT from 0.039 min-1 to 0.054 min-1 (increased by 38%), while kCT decreased by 61.5% and 64% when increasing the concentration of HCO3- and humic acid (HA) to 15 mM and 15 mg L-1, respectively. CT degradation was inhibited …
The Effect Of Fuel On The Physiochemical Properties Of Znfe2o4 Synthesized By Solution Combustion Method, Fahma Riyanti, Widia Purwaningrum, Nova Yuliasari, Sasmita Putri, Nabila Aprianti, Poedji Loekitowati Hariani
The Effect Of Fuel On The Physiochemical Properties Of Znfe2o4 Synthesized By Solution Combustion Method, Fahma Riyanti, Widia Purwaningrum, Nova Yuliasari, Sasmita Putri, Nabila Aprianti, Poedji Loekitowati Hariani
Turkish Journal of Chemistry
The synthesis of ZnFe2O4 nanoparticles was performed using the solution combustion method with three types of fuel, namely urea, glycine, and ethylenediamine tetra-acetic acid (EDTA) with precursors (Zn(NO3)2.6H2O and Fe(NO3)3.9H2O. The combustion process was conducted in an open space at 300 °C for ± 1 h, resulting in a brownish-black ZnFe2O4. Meanwhile, the fuel type used in the process affects the physicochemical properties of ZnFe2O4. XRD analysis showed that ZnFe2O4 synthesized using urea, glycine, …
Single-Side Polypyrrole Coated Conductive And Flexible Polyurethane Films, Meli̇s Bi̇lal, Esma Sezer, Belkis Ustamehmetoglu
Single-Side Polypyrrole Coated Conductive And Flexible Polyurethane Films, Meli̇s Bi̇lal, Esma Sezer, Belkis Ustamehmetoglu
Turkish Journal of Chemistry
In this study, single-side polypyrrole (PPy) coated conductive stretchable polyurethane (PU) / PPy composite films were synthesized by chemical oxidative method in the acetonitrile (ACN)/H2O interface as a new alternative to two-side coated PU films which have already reported in the literature. One surface of the PU film was contacted with aqueous Py solution and the other surface with cerium ammonium nitrate (CAN) solution in ACN, so that only one surface of the film was coated with PPy and the resulting composite was named PU/PPy (PUP). This composite was characterized by four-point probe conductivity measurement, Fouriertransform infrared spectroscopy …
Improvement Of Hydrodynamics And Heat Transfer In Biomass Fluidized Bed Combustor With Immersed Tubes Using Cfd-Dem, Krittin Korkerd
Improvement Of Hydrodynamics And Heat Transfer In Biomass Fluidized Bed Combustor With Immersed Tubes Using Cfd-Dem, Krittin Korkerd
Chulalongkorn University Theses and Dissertations (Chula ETD)
Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) has been extensively utilized for studying hydrodynamics and heat transfer in fluidization processes. This study specifically focuses on improving hydrodynamics and heat transfer in a biomass fluidized bed combustor with immersed tubes. The investigation involves the use of mixed biomass, exploring the effects of biomass types, biomass loading, and blending ratios to propose criteria for selecting suitable biomass fuel for the system. Design parameters related to the immersed tubes, such as the angle between tubes, tube diameters, and distance between tubes, were also considered. A data-driven model was developed based on …
Chemical Constituents From The Fresh Pericarps Of Mature Mangosteen Fruit Garcinia Mangostana, Ahmad Tijani Azeez
Chemical Constituents From The Fresh Pericarps Of Mature Mangosteen Fruit Garcinia Mangostana, Ahmad Tijani Azeez
Chulalongkorn University Theses and Dissertations (Chula ETD)
α-Mangostin has been identified as a major chemical constituent in the pericarps of mangosteen (Garcinia mangostana Linn.) Over time, dried pericarps of mangosteen have been subjected to studies in literature. This study aimed to explore isolation of α-mangostin and other chemical constituents from the fresh pericarps of mature mangosteen fruits and investigate their relative antioxidant and anticancer activities. Repeated column chromatography on ethyl acetate and methanol extracts of fresh mature mangosteen pericarps led to the isolation of α-mangostin (33.25% of crude extracts) as the major compound, beta-mangostin (0.225%) and gartanin (7.57%). Their antioxidant scavenging activity was investigated against 2,2-diphenyl-1-picrylhydrazyl (DPPH) …
Simultaneous Extraction And Colorimetric Detection Of Ions Using Gel Electromembrane, Ali Sahragard
Simultaneous Extraction And Colorimetric Detection Of Ions Using Gel Electromembrane, Ali Sahragard
Chulalongkorn University Theses and Dissertations (Chula ETD)
A total integrated electrocolorimetric sensing approach consisting of gel-based electromembrane extraction and colorimetric detection in one-step process was developed. This system was designed using colorimetric reagents preadded to the agarose gel for the determination of the following two model analytes: iodide for negative ions and nickel for positive ions. In this system, when a voltage was applied, the analytes were extracted and transferred from the sample solution (donor phase) to the gel (acceptor phase). The analytes then simultaneously reacted with the colorimetric reagents inside the gel, yielding blue and pink colors for iodide and nickel ions, respectively. These colors were …
Fluorescent Hydrazine-Naphthalimide Encapsulated By Ethyl Cellulose For Detection Of Long-Chain Aldehydes, Faiza Lawan Isah
Fluorescent Hydrazine-Naphthalimide Encapsulated By Ethyl Cellulose For Detection Of Long-Chain Aldehydes, Faiza Lawan Isah
Chulalongkorn University Theses and Dissertations (Chula ETD)
One of the most common diseases globally which takes numerous lives is lung cancer. The high concentrations of aldehydes found in tobacco smoke and motor vehicle exhaust are among the contributors for lung cancer. There is a lot of interest in developing a nanosensor for identifying long-chain aldehydes. The conventional methods for detecting aldehyde are highly complex, expensive, and time-consuming. To overcome this drawback, alternative detection techniques such as fluorescence techniques are needed for the quick, easy, and affordable identification of aldehydes. Aldehyde molecules and their derivatives are often used as biomarkers to aid in the diagnosis and treatment of …
Deep Eutectic Solvent-Coated Paper-Based Device For Colorimetric Detection Of Chromium(Vi), Fakhry Gripaldi Pandu
Deep Eutectic Solvent-Coated Paper-Based Device For Colorimetric Detection Of Chromium(Vi), Fakhry Gripaldi Pandu
Chulalongkorn University Theses and Dissertations (Chula ETD)
Hexavalent chromium, Cr(VI), is one of the heavy metal ions often found in the environment that is highly toxic and classified as a carcinogen. In this work, rapid screening and onsite monitoring of Cr(VI) using paper-based has been developed. Furthermore, a natural-based deep eutectic solvent, comprising choline chloride and thymol that makes it an environmentally friendly solvent, is applied as a coating medium on the test strips for qualitative and quantitative analysis of Cr(VI) for the first time. 1,5-Diphenylcarbazide was used as an indicator and complexing agent for Cr(VI). The detection was conducted by using a smartphone equipped with an …
Use Of Layered Double Hydroxides As Ionophore For Anion Selective Electrode, Kittipong Konraeng
Use Of Layered Double Hydroxides As Ionophore For Anion Selective Electrode, Kittipong Konraeng
Chulalongkorn University Theses and Dissertations (Chula ETD)
Layered double hydroxides (LDHs) or hydrotalcite compounds are referred to anionic clays with specific anion adsorption and exchanging properties. These behaviors are similar to ionophores and ionic additives in ion selective electrodes (ISEs). Therefore, in this study LDHs was used to function as tailor-made ionophores for particular anions and ionic additives in ISEs. MgAl LDHs were prepared, and then modified the intercalated anions to be NO3-. The selective polymeric membrane was casted using PVC and MgAl LDHs-NO3-. The membrane containing 30%(w/w) MgAl LDHs-NO3- showed the best ISE characteristics toward NO3- with response slopes of -51.31 mV decade-1 in the concentration …
Colorimetric Detection Of Norfloxacin And Ceftazidime By Modified Materials, Lalitphan Hongtanee
Colorimetric Detection Of Norfloxacin And Ceftazidime By Modified Materials, Lalitphan Hongtanee
Chulalongkorn University Theses and Dissertations (Chula ETD)
Novel approaches were developed for the colorimetric detection of norfloxacin and ceftazidime using chemically modified polymer resin and cotton sponge as sensing materials, respectively. For norfloxacin detection, the optimum condition was achieved by using a resin modified with 6.0 µM Congo red at pH 6 to extract norfloxacin in 10 mL of sample at pH 2. The reaction was completed within 15 minutes. Regarding ceftazidime detection, a cotton sponge functionalized with polyethyleneimine (PEI) was fabricated and characterized by FTIR, SEM, and ninhydrin test. To fabricate the PEI-sponge, 170 mM 3-aminopropyl triethoxysilane (APTES) was used to modify 1.0 g cotton fibers …
Nickel Complexes Containing N4 Schiff-Base Macrocycles Dereived From Diphenylamine-2,2'-Dicarboxaldehyde For Catalytic Co2 Reduction, Methasit Juthathan
Nickel Complexes Containing N4 Schiff-Base Macrocycles Dereived From Diphenylamine-2,2'-Dicarboxaldehyde For Catalytic Co2 Reduction, Methasit Juthathan
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this dissertation, nickel(II) complexes featuring N4-Schiff base macrocycles derived from diphenylamine-2,2'-dicarboxaldehyde (1-Ni and 2-Ni) with a new crystal structure ([2-Ni]Me) were synthesized and investigated for electrochemical CO2 reduction (ECR). Cyclic voltammetry (CV) of two nickel complexes, 1-Ni and 2-Ni, illustrated the catalytic response whereas one, [2-Ni]Me, virtually remained peak-shaped in the presence of CO2, indicating the feasibility of ECR activity for these nickel complexes. To develop heterogeneous ECR catalysts in aqueous media, all nickel complexes were adhered on N-doped graphene (NG) through non-covalent interaction, obtaining Ni@NG hybrid catalysts. The Ni@NG catalysts showed satisfactory ECR activity with the faradaic efficiency …
Enhancement Of Ammonia Gas Sensing By Metal Oxide-Polyaniline Nanocomposite, Nattawut Soibang
Enhancement Of Ammonia Gas Sensing By Metal Oxide-Polyaniline Nanocomposite, Nattawut Soibang
Chulalongkorn University Theses and Dissertations (Chula ETD)
Ammonia (NH3) gas is an important chemical in many industries. Employees who work in those industrial areas may exposed to a certain concentration of NH3 which could cause various symptoms such as irritation of skin and eyes and problems in respiratory system. The development of new NH3 sensing material has drawn a great attention. In this study, porous tin dioxide nanofibers (SnO2 NFs) were successfully fabricated by an electrospinning technique. The SnO2 NFs were composited with polyaniline (PANI), conducting polymer and form tin dioxide nanofibers@polyaniline nanocomposite (SnO2 NFs@PANI). The morphology was characterized using SEM-EDS and XRD. The SnO2 NFs@PANI was …
Emulsification Microextraction Using Surfactant Coupled With Colorimetric Detection For Determination Of Synthetic Dyes In Food, Niluh Indria Wardani
Emulsification Microextraction Using Surfactant Coupled With Colorimetric Detection For Determination Of Synthetic Dyes In Food, Niluh Indria Wardani
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this thesis, solidification of floating organic drop-emulsification liquid-liquid microextraction (SFOD-ELLME) was combined with digital image colorimetry (DIC) for the analysis of synthetic dyes, such as rhodamine B (RhB) and crystal violet (CV) in food and drink samples. Here, the extraction was performed by using emulsified fatty acid surfactant and freezing procedure to separate the extracting phase. The solidified floating organic drop was then taken out, liquified and dropped on the paper platform for digital image colorimetric analysis. The response surface methodology-central composite design (RSM-CCD) was used to optimize some variables that influence the extraction efficiency. A sample of 7 …
Development Of Dna Detection System Using G-Quadruplex As Catalyst For Colorimetric Detection With Pyrrolidinyl Peptide Nucleic Acid, Somlawan Thipkunthong
Development Of Dna Detection System Using G-Quadruplex As Catalyst For Colorimetric Detection With Pyrrolidinyl Peptide Nucleic Acid, Somlawan Thipkunthong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Nucleic acid sequence detection is very important for many applications such as the diagnosis of genetic diseases. The development of new, simple yet effective methods is still in great demand. Among several options, colorimetric detection is a technique that does not require complicated instruments and allows the detection by naked eyes. In this work, a new colorimetric DNA detection system was developed using the combination of a pyrrolidinyl peptide nucleic acid (acpcPNA) probe and a G-quadruplex/hemin DNAzyme. The G-quadruplex is formed from G-rich DNA sequences, and in the presence of hemin, a DNAzyme is formed which effectively catalyzes the oxidation …
Prediction Of Soil Sorption Coefficient Of Chemicals By Molecular Modeling Technique, Wasin Pithaktrakool
Prediction Of Soil Sorption Coefficient Of Chemicals By Molecular Modeling Technique, Wasin Pithaktrakool
Chulalongkorn University Theses and Dissertations (Chula ETD)
Soil pollution is one of the pollutions caused by nature and human activities, which are mostly the use of insecticide and chemical fertilizer to make plants grow well and produce more products. However, these chemicals are absorbed by soil. In this research work, properties of chemical compound affecting soil sorption were analyzed, and model that can predict soil sorption coefficient of chemicals (KOC) was examined by using quantitative structure property relationship (QSPR) technique. Totally 1,327 compounds were selected, and their three-dimensional structures were constructed. Semi-empirical PM7 method was used for geometry optimization calculations. A total of 1,536 physicochemical properties were …