Phromyothin, Darinee

Preferred name

Alternative Name

Phromyothin, D.

Phromyothin, Darinee Sae Tang

Main Affiliation

Integrated Innovative Technology

darinee.ph@kmitl.ac.th

Now showing 1 - 10 of 40

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Quantum chemical study of Thiadiazole molecular sensors for detection of heavy metal, A DFT calculation
(2017-01-01)
Chattrairat, K.
;
Phromyothin, D.
Using density functional theory (DFT), the binding energies, band spectra, optical properties and electron distribution of thiadiazole derivatives were investigated to detect the metals. The results indicate that the molecular sensors M1 and M3 can detect Pb2+ with the lowest binding energy. The electron density distributions show a transfer of electron from the aromatic group of the molecular sensor fluorophore to the metal ion when a photon is absorbed.
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Tantalum oxide bio-photonics thin film grown by gas-timing innovation technique
(2013-09-18)
Khemasiri, N.
;
Porntheeraphat, S.
;
Horprathum, M.
;
Chananonnawathorn, C.
;
Bunjongpru, W.
Tantalum oxide (TaxOy) as high refractive index material has been grown on p-type silicon and quartz substrates by R.F. magnetron sputtering with our innovative technique called "reactive-gas timing". The reactive gas timing technique is an on-off time period sequence between argon (Ar) and oxygen (O2) plasma during sputtering process. The technique of gas-timing plays the effect on the properties of TaxOy thin film. The bombarded Ar-plasma was varied at 2, 5 and 8 sec, while the period of reactive O2-plasma was kept at 5 sec in this experiment. The physical and optical properties were investigated by using X-ray diffraction (XRD), Atomic Force Microscope (AMF), UV-Visible spectrometer and Spectroscopic Ellipsometer, respectively. The XRD spectra and AFM photographs show all films are amorphous phase with smooth feature. Meanwhile the transmittance of sputtered thin film decreases with 10% and the absorption edge shifts to lower energy with the increasing of the argon period from 2 sec to 8 sec. The refractive index as showed by ellipsometry slightly increases from 2.08 to 2.17 at wavelength 550 nm with the increasing of argon period from 2 sec to 8 sec. The increasing of the refractive index might dues to tantalum (Ta) rich which consists in thin films. The Ar-plasma period in the deposited film plays an important role on the properties of the TaxOy thin films especially as optical refractive index material. © 2013 SPIE.
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Efficeincy improvement of triphenylamine-based organic dyes in DSSCs, an effects of linker moiety
(2013-10-29)
Chittratan, P.
;
Thanakit, P.
;
Jarernboon, W.
;
Phromyothin, D.
Triphenylamine-base organic dyes were designed and investigated for dye-sensitized solar cells (DSSCs). The dye molecules consist of three parts, an electron-donor connected by the π- conjugated linker (benzene and thiophene) as an electron spacer and an acceptor/anchoring (cyanoacrylic acid). In this study, quantum chemical calculations were used to study the electronic properties, optical properties and density of electron in the linker of dye molecule by using the density functional theory. The results present that thiophene is the most appropriate to use as electron linker between triphenylamine donor and acrylic acceptor due to the wide of absorption band and π-conjugate bond effect on exhibiting red-shifted absorption spectra. © (2013) Trans Tech Publications, Switzerland.
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Improving Stability of Nanoemulsion Containing Centella asiatica, Lycopersicon Esculentum Mil. And Moringa oleifera Lam. Extract
(2019-01-01)
Limthin, Darawan
;
Phromyothin, Darinee
Natural extracts are interesting because those have bioactive compounds which can be used as antioxidants in pharmacological cosmetics. However, bioactive compounds are unstable to environment. In the present study, formulation and stability of Centella asiatica, Lycopersicon Esculentum Mil. and Moringa oleifera Lam. was performed using high shear homogenization (HSH) technique. Virgin coconut oil was based of oil phase for emulsion. The optimum formulation of the nanoemulsion consisted of 80:10:10 of water, tween 80 and oil, respectively. 1 % of natural extract nanoemulsion was homogenized for 20 minutes at 4,000 rpm. and stored at 4 ºC, 25 ºC and 40 ºC for 7 days. Particles size and electrokinetic potential of emulsion extract was determined by dynamic light scattering method. Single-phase solution and droplet size was observed in the range of 100 to 500 nm. The droplet size and stability of emulsions depends on temperature and times storage, which this study would be approached to develop a natural product in cosmetic market.
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Functionalized magnetic nanoparticles as chemosensors based on fluorene derivative for Cd(II) ions detection
(2019-11-18)
Thanakit, P.
;
Limthin, D.
;
Leepheng, P.
;
Suramitr, S.
;
Phromyothin, D.
Chemosensor of fluorene derivative (FL) contains different conjugated aromatic rings and binding sites that indicate the maximum fluorescence spectra at 505 nm in dimethylformamide solvation. The emission color is sensitive to changes in acidity and basicity solution which explain in twisted-intramolecular charge transfer and results in a sensitivity of metal ions. At neutral solution (pH 7), these molecules are sensitive to Cd(II) ions which illustrate red-shifted fluorescence spectra and the increase of Cd(II) ions concentration results in the increases of the fluorescence intensity. The limit of detection (LOD) of Cd(II) ions is 0.289 mg/L. The presence of other metal ions in Cd(II)-complexes shows the selectivity of Cd(II) ions and was not significantly sensitive to other metal ions. The carboxylic binding sites of FL chemosensor are important to interact with Cd(II) ions in dimethylformamide solvation and the cyano moiety can withdraw the charge transfer to binding site results in fluorescence intensity increasing. In addition, superparamagnetic iron oxide nanoparticles (SPIONs) were used to improve signal fluorescence intensity for Cd(II) ions detection which lead to the lower limit of detection. The surface of SPIONs was modified with PMMA that it exhibits the decreased agglomeration of SPIONs. Then, the suspension of fluorescent magnetic nanoparticles was showed the good solubility in dimethylformamid when FL was coated on the PMMA/SPIONs.
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An experimental and theoretical study of molecularly imprinted electrode based on methyl methacrylate polymer for pesticide detection
(2020-06-01)
Leepheng, Piyawan
;
Limthin, Dalawan
;
Homchan, Wisa
;
Suramitr, Songwut
;
Phromyothin, Darinee
A selective electrode based on molecularly imprinted polymer (MIP) was developed by the polymerization of methyl methacrylate polymer on a screen-printed electrode for pesticide detection. Cypermethrin is one of the pesticides in the pyrethroid group, which has high toxicity in an organism and humans and causes environmental pollution. Cypermethrin-MIP and non-imprinted polymer films on electrodes were characterized for their surface morphology. The electrochemical analysis of cypermethrin pesticide was measured by amperometry under the potential of -0.23 V versus Ag/AgCl. Decreasing the current was directly proportional to the concentration of cypermethrin in the range of 15.50 ppb-10.00 ppm, and the limit of detection value was calculated to be 15.00 ppb. The proposed modified electrode has high sensitivity of 0.094 μA ppm-1 and effective selective detection of cypermethrin in samples of real vegetable juice. The computational analyses were performed with the density functional theory at M06-2x/6-31 g(d,p), which predicted interaction and study mechanism between the MIP matrix with target pesticides.
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DFT-based computational investigation on functional monomer and solvent selection of molecularly imprinted polymers for recognition of chlorpyrifos organophosphate insecticide
(2020-01-01)
Chittratan, Pakawat
;
Phromyothin, Darinee
;
Monvisade, Pathavuth
Density functional theory calculation was used to investigate the appropriate monomer and solvent for the preparation of chlopyrifos organophosphate molecularly imprinted polymers. The polymerization process of MIPs contained four essential elements, i.e. template, monomer, cross-linker and porogenic solvent. A computational chemistry was applied to optimize the polymerization system. Seven commonly used monomers, involving methacrylic acid, acrylic acid, acrolein, acrylonitrile, acrylamide, methacrylamide, and 4-vinylpyridine were studied. Stable complex interaction between chlopyrifos and monomer was chosen from the binding energies. Solvation effect was studied using the polarizable continuum model (PCM) for acetonitrile, tetrahydrofuran, toluene and dichloromethane. The appropriate monomer and solvent were selected from the results of the calculation and the most suitable solvent was chosen by the less effect on the interaction. The best pre-polymerization conditions are useful to synthesize MIPs for specific recognition of chlorpyrifos organophosphate insecticide molecule.
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Diptoindonesin D, a potent antibacterial activity against gram-positive bacteria, an inhibitor of penicillin-binding protein 2a from the stem bark of Shorea roxburghii G.Don
(2019-11-01)
Sudto, Kanokorn
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Saparpakorn, Patchreenart
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Tancharoen, Chompoonuch
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Phromyothin, Darinee
;
Techasakul, Supanna
The emergence and spread of antimicrobial resistance (AMR) is a serious threat to public human health. The challenge now is an urgent need to new potent antibiotics combating AMR which can be an effective way to solve the crisis. A new potent antibacterial activity of diptoindonesin D, together with four known compounds as hopeafuran, α-viniferan, hopeahainol A and hopeahainol C were isolated from the stem bark of Shorea roxburghii G. Don in Khon Kaen province, Thailand. Diptoindonesin D were screened for antimicrobial activity and possesses significant activity minimum inhibitory concentrations (MIC) values of 4.68 and 9.37 μg/mL against Staphylococcus epidermidis and Staphylococcus aureus, respectively. The absolute configuration of diptoindonesin D were evaluated by circular dichroism (ECD) calculations. The ECD results indicated that the possible configuration of diptoindonesin D should be R-configuration. Furthermore, reverse docking was performed to identify the protein target of diptoindonesin D based on four scoring functions using GOLD program. This investigation is the first time that reveals interaction between diptoindonesin D and its binding with cell wall synthesis protein targets. The results highlighted that, penicillin-binding protein 2a (PBP2a), an antibacterial cell wall, might be the potential target for the binding of diptoindonesin D. The obtained results can be useful as a guideline for the development of effective diptoindonesin D as a PBP2a inhibitor.
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A study of fluorescent chemosensor for Fe(II) based on cyanoacrylic derivatives
(2013-10-29)
Thanakit, P.
;
Chodjarusawad, T.
;
Chittratan, P.
;
Pratontap, S.
;
Phromyothin, D.
A chemosensor based on a cyanoacrylic (DTP-C) consists of dithieno [3,2-b;2',3'- d]pyrrole(DTP) as a chromophore and a cyanoacrylic moiety as an ionophore which linked by aromatic system. DTP-C demonstrates the response of complex with Fe(II) in dimethylformamide (DMF) solution. The binding mode of Fe(II)/DTP-C complex was characterized using UV-Visible and fluorescence spectroscopy. In addition, the effect of various MES buffer was then studied at 5%, 10%, 15% and 20% v/v in Fe(II)/DTP-C complex which the appropriate ratiomatric of MES buffer is 10%. The enhancement of Fe(II) concentration indicate a decrease emission intensity while the addition of buffer concentrations found to increase in the intensity. Moreover, quantum chemical calculations were used to study the electronic and optical properties of the molecular structure of DTP-C under the density functional theory. © (2013) Trans Tech Publications, Switzerland.
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Preparation of surface-modified electrode of copper(ii) oxide mixed with the molecularly imprinted polymer for enhancement of melamine detection with photoelectrochemical technique
(2023-05-15)
Limthin, Dalawan
;
Leepheng, Piyawan
;
Tunhoo, Benchapol
;
Onlaor, Korakot
;
Klamchuen, Annop
Melamine contamination in food and beverages affects short- and long-term health. In this work, enhanced sensitivity and selectivity in photoelectrochemical determination for melamine detection was achieved using copper(ii) oxide (CuO) combined with a molecularly imprinted polymer (MIP). A CuO nanomaterial was used to achieve MIP surface modification via co-precipitation synthesis. An MIP film was deposited by polymerizing the methacrylic acid monomer and a melamine template. The properties of the CuO nanomaterials, such as the surface morphology, chemical oxidation state, and crystalline structure, were characterized using field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction patterns (XRD), respectively. The diffuse reflection spectroscopy technique was applied to evaluate the optical properties of the CuO nanoparticles. The results indicated that the synthesized CuO nanomaterials had a monoclinic structure with an optical bandgap of 1.49 eV, which corresponds to absorbance in the visible light region. CPE electrodes with surface-modified CuO/MIP were measured using the photoelectrochemical techniques of cyclic voltammetry, differential pulse voltammetry (DPV), and amperometry. The modified CuO/MIP electrode for melamine detection in 7.4 pH PBS buffer solution exhibited a high sensitivity of 0.332 nA nM−1, with a linear range of 5.0-75.0 nM and a limit of detection of 2.45 nM. Moreover, real samples of various kinds of milk were applied to evaluate the sensing response of the prepared CuO/MIP electrode. The modified CuO/MIP electrodes could be reused seven times with good reproducibility and high selectivity for melamine detection.

Phromyothin, Darinee

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