Choengchan, Nathawut

Preferred name

Alternative Name

Choengchan, N.

Choengchan, Nuthawut

Main Affiliation

School of Science

nathawut.ch@kmitl.ac.th

Now showing 1 - 10 of 18

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A new coumarin-based “OFF–ON” fluorescent sensor for H2S detection in HeLa cells
(2025-02-05)
Sontisiri, Pakornsiri
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Promrug, Dusit
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Arthan, Dumrongkiet
;
Choengchan, Nathawut
;
Thongyoo, Panumart
A new “OFF–ON” coumarin-based fluorescent probe for H<inf>2</inf>S detection was designed and successfully developed through O-sulfonylation between a dabsyl quencher and 7-hydroxy-4-methylcoumarin as a fluorescent reporter, based on a FRET approach. This H<inf>2</inf>S responsive probe, utilizing H<inf>2</inf>S assisted thiolysis of a sulfonate ester as the sensing strategy, demonstrated excellent performance towards H<inf>2</inf>S with a limit of detection (LoD) of 1.64 µM, along with superb selectivity, good stability and high specificity towards H<inf>2</inf>S without interference from other biomarkers and analytes. Moreover, dabsyl-7-hydroxy-4-methylcoumarin (dabsylcoumarin) is capable of permeating the cell membrane and effectively visualizing the level of H<inf>2</inf>S in the living HeLa cells without cytotoxicity.
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Low-cost synthesis of gold nanoparticles from reused traditional gold leaf and its application for sensitive and selective colorimetric sensing of creatinine in urine
(2020-01-01)
Mathaweesansurn, Arjnarong
;
Choengchan, Nathawut
;
Khongkaew, Putthiporn
;
Phechkrajang, Chutima M.
Background: Gold nanoparticles (Au NPs) are normally prepared using standard gold (III) trichloride which is much expensive and irritant. This work is aimed at demonstrating simple and low-cost synthesis of Au NPs from the reused traditional gold leaf which is cost-free and less toxic. Methods: The reused gold leaf was donated by the local temple. It was digested and used as the precursor for the preparation of the Au NPs by Turkevich method. Poly (vinyl alcohol) (PVA) was em-ployed as a stabilizer. The as-prepared Au NPs were applied for the colorimetric determination of creatinine in urine without any sample pretreatment. Results: Long-term stability of the gold colloids was achieved for at least 3 months. Morphology and purity of the as-prepared Au NPs were the same as the ones prepared from standard gold (III) salt and standard gold foil. Colorimetric response of the Au NPs was linear to the standard creatinine up to 200 mg L-1. The limit of detection (0.16 mg L-1 or 1.41 µM) was enough sensitive for urinary cre-atinine detection in patients with kidney disease. Good recoveries (97-108%) and fast analysis time (3 min) were achieved. The developed method was successfully validated against the HPLC method. Conclusion: Facile and cost-effective synthesis of the Au NPs from the reused traditional gold leaf, was accomplished. The as-prepared Au NPs were successfully applied for the determination of urinary creatinine with high sensitivity and selectivity.
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A Double-layered Paper-based Analytical Device for Determination of Iron in Water Samples based on Standard Addition Method
(2024-01-03)
Srikritsadawong, Pongpichet
;
Sookpotarom, Punyapat
;
Thongchan, Surachet
;
Choengchan, Nathawut
A simple method for the determination of iron involved a novel paper-based analytical device (PAD) was developed. The PAD was composed of two layers. Each layer contained a circular hydrophilic reservoir (10 mm Ø) that was situated in a rectangular filter paper (25 Î 25 mm2). The hydrophobic area was created by painting the paper with a “waterproof” glue. The top and the bottom layers were assigned as “the filtration” and “the detection” platforms, respectively. The procedure was started by pipetting an aliquot of bathophenanthroline (Bphen) onto the hydrophilic zone of the bottom layer followed by spiking of standard solutions (0.1-0.5 mgL-1 Fe2+). The red complex was developed. Then, the top and the bottom layers were assembled by two-sided mounting tape. Later, a water sample was dropped onto the top layer, which removed (filtered) any suspended particles in the water sample. When the filtrate was exposed to the bottom layer, a further colored product formed. The bottom layer was removed and placed in a light-controlled box, and the optical image of the product was captured using a smartphone. Its intensity was evaluated through ImageJ™. Linear standard addition plots were obtained (r2 > 0.99). The PAD provided high precision (RSD < 6%) with good recovery (92.6-102%). It was applied to the analysis of drinking, tap, canal and river water samples without any prior filtration. The iron amounts were compared to the results obtained by the spectrophotometric method, and there was not significantly difference at 95% confidence (Paired-t test, n = 5 samples, t<inf>stat</inf> = 2.68, t<inf>cri</inf> = 2.78).
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Towards direct analysis of solid and liquid samples exploiting a 3D printed dialysis unit and sequential injection: Application for automated derivatization and determination of gamma-aminobutyric acid in foodstuff and beverages
(2020-02-08)
Kasetsoontorn, Bhoonnarasa
;
Choengchan, Nathawut
In this work, a new design of a dialysis unit for direct analysis of solid and liquid samples is presented. The homemade unit was constructed using a 3D printer due to its simple and fast fabrication ability. The dialysis unit is composed of cylindrical-shaped donor and acceptor chambers. A stainless steel sieve is installed inside the donor chamber. SEM images clearly showed that the sieve prevented membrane blockage by suspension particles in the sample. Multiple dialysis units were connected to a sequential injection (SI) system for serial determination of gamma-aminobutyric acid (GABA) in solid and liquid samples. The dialysate from each dialysis unit was consecutively aspirated into the SI flow line for on-line derivatization of GABA with 2-hydroxy-1-naphthaldehyde (3.0% w/v). The derivative was detected spectrophotometrically at 425 nm. The linear calibration range extended to 1000 mg L−1 GABA (r2 > 0.99) with high precision (1.2 %RSD). The developed system was applied to analysis of dietary supplements, grains of germinated brown rice and milk. The samples were directly introduced into the donor chamber either as powder or liquids. The measured GABA content using the developed method was compared using high performance liquid chromatography, with good agreement using Pearson's correlation (r2 = 0.9999). The method has high accuracy based on recovery studies (99.8 ± 1.5%) and high sample throughput (64 samples h−1).
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Multi-well plate as headspaces for paper-based colorimetric detection of sulfur dioxide gas: An alternative method of sulfite titration for determination of formaldehyde
(2023-01-25)
Yodpach, Nattapon
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Chantiwas, Rattikan
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Wilairat, Prapin
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Choengchan, Nathawut
;
Praditweangkum, Wiboon
This work describes the analysis of formaldehyde using a 96-well microplate as multiple headspaces for the separation of sulfur dioxide gas generated from the sulfite remaining after its reaction with the formaldehyde in the sample. The quantitation of the gas is by colorimetric detection of an indicator paper placed over the microplate. The samples are aqueous extracts of various foods that are possibly adulterated with formaldehyde. A known excess amount of sulfite is added to the extract solution aliquoted in the well. The remaining sulfite is acidified with hydrochloric acid to generate sulfur dioxide gas which diffuses through the headspace above the solution to be absorbed at the moist strip of the indicator paper placed over the mouth of the wells. Anthocyanins extracted from the butterfly pea flower is used as the pH indicator giving a color change from the increase of hydrogen ions by hydrolysis of the absorbed sulfur dioxide gas. The exposed paper strip is scanned, and the digital images of the colored region analyzed using ImageJ software. The optimized method has a linear range of 200–1000 mg L−1 formaldehyde with limit of detection ((2.57*SD of intercept)/(slope of calibration line)) of the aqueous extract of 40 mg L−1 and coefficient of determination (r2) > 0.9979. Samples of fresh produce, such as seafood, meat, and vegetables, and various processed food were analyzed for their possible formaldehyde content. The results obtained from the headspace paper-based colorimetric detection are not statistically different from the values obtained from the titration method by paired t-tests.
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Superhydrophobic eggshell for fabrication of hydrophobic barrier of paper-based analytical device for colorimetric determination of ammonium ion in water
(2024-05-01)
Thangjitsirisin, Kanyapak
;
Seeharaj, Panpailin
;
Choengchan, Nathawut
This work demonstrates the first application of the superhydrophobic eggshell as an environmental-friendly material for fabricating the hydrophobic barrier of a paper-based analytical device (PAD). The eggshell surface was modified by mixing the pulverized chicken eggshell biowaste with stearic acid and a polystyrene binder to accomplish superhydrophobicity. The PAD (10 × 10 mm2) is comprised of the circular-shaped hydrophilic reservoir (Ø 5 mm). The liquid barrier was fabricated by painting both the topside and the underside of the filter paper with the dispersed superhydrophobic eggshell solution. The SEM images revealed that the microsized superhydrophobic eggshell particles absorbed onto the porous surface of the cellulose fibril. A coated surface with a water contact angle of 155.39° ± 1.02° (n = 10) on the paper substrate was achieved, and this indicated superhydrophobicity. The eggshell barrier enabled excellent water and chemical resistance. The fabricated PAD was applied for the colorimetric determination of ammonium cations (NH<inf>4</inf>+), based on the modified Berthelot reaction. Samples and chromogenic solutions were aliquoted onto the hydrophilic reservoir, with subsequent capture of the optical image of the stable, green-colored product by a smart phone under a light-controlled studio. The green color intensities were evaluated by ImageJ™ and plotted against the standard NH<inf>4</inf>+ concentrations. A wide linear calibration range 5.0 to 100 mg N/L was achieved with good linearity (r2 > 0.99). The PAD confirmed satisfied analytical recovery (Mean ± SD: 100.6 % ± 0.97, n = 11 samples) and high precision (RSD = 0.85 %: 10-PAD replicate measurements of 1.0 mg N/L). The limit of detection (3 SD of blank/slope) of 1.05 mg N/L was found sensitive enough to monitor the NH<inf>4</inf>+ contents in freshwater. The results, determined by the developed PAD and ion chromatography, showed no significant difference under the statistical paired t-test at 95 % confidence (t<inf>stat</inf> = -1.80, t<inf>cri</inf> = 2.57, n = 6 samples).
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Simple flow system with in-line gas-diffusion unit for determination of ethanol employing hypsochromic shift of visible absorbance band of methyl orange
(2020-01-01)
Ratanawimarnwong, Nuanlaor
;
Sinpun, Montatip
;
Chankaw, Panuwat
;
Choengchan, Nathawut
;
Nacapricha, Duangjai
The effect of solvent composition on the uv–visible spectrum of methyl orange was investigated for application to the quantitative determination of ethanol. At fixed pH, there was a hypsochromic shift of the absorbance band of methyl orange with increasing ethanol concentration. Using acetate buffer at pH 3.40 the change of absorbance at 530 nm of a solution of methyl orange containing known concentrations of standard ethanol was measured to provide a calibration curve. In order to apply this method to the analysis of alcoholic samples, such as distilled spirits, blended spirits and liquid herbal medicines, a simple gas-diffusion unit coupled with flow system was employed to separate the ethanol from sample matrices. Using the gas diffusion-flow system and employing an evaporation time of 2 min, a linear calibration range of 5–45% (v/v) ethanol was achieved ((ΔA = (0.0078 ± 0.0002)x(ethanol, %(v/v)) + (0.040 ± 0.005)), r2 = 0.998). The limit of detection (3σ blank/slope) was 2.23% (v/v). The developed gas diffusion-flow system was applied to the analysis of colorless distilled spirits, yellow blended spirits and dark brown herbal medicines that are available in the local markets of Bangkok, Thailand. Validation of the method was carried out by comparing the results with analysis using gas chromatography. There was no statistically significant difference at the 95% confidence level for all alcoholic samples analyzed.
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Direct determination of ethanol in alcoholic beverages based on its anti-aggregation of melamine-silver nanoparticle assembly
(2022-12-01)
Duangdeewong, Chomphunud
;
Choengchan, Nathawut
;
Wattanasin, Panwadee
;
Teerasong, Saowapak
We report a new method for determination of ethanol based on anti-aggregation of silver nanoparticles (AgNPs) in the presence of melamine. In the system, ethanol and melamine act as protecting and aggregating agents, respectively. Melamine can induce citrate-stabilized AgNPs to aggregate, leading to a color change from yellow to green. However, if the AgNPs are pre-incubated in ethanol, ethanol readily surrounds the particles by forming hydrogen bonds with the citrate stabilizer. An external nanoshell of ethanol hinders particle aggregation caused by melamine. Minor aggregation of AgNPs was observed, the solution color maintained its yellow-orange color. Higher ethanol concentrations result in a lower degree of particle aggregation. The colorimetric response of AgNPs was monitored using a UV–vis spectrophotometer at 390 nm. The current method could determine ethanol concentrations over a wide dynamic range of 5–80% (v/v), with a detection limit of 3.1% (v/v) (3SD of blank/slope). This method was applied for direct quantification of ethanol in alcoholic drinks without sample pretreatment and the results are well correlated with those of gas chromatography. Our method is convenient and cost effective, making it auspicious for ethanol monitoring in alcoholic drink manufacture and control.
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A double-layered paper-based analytical device for speciation and simultaneous determination of iron in waters within single-shot analysis
(2025-08-01)
Thongchan, Surachet
;
Sookpotarom, Punyapat
;
Praditweangkum, Wiboon
;
Thongyoo, Panumart
;
Sojic, Neso
This work demonstrates the use of a paper-based analytical device (PAD) for the speciation and the simultaneous determination of iron (Fe) in waters within a single-shot analysis. The PAD is designed as having stacked, double layers viz., the topside and underside layers. Each layer (25 × 25 mm2) consists of a defined circular hydrophilic reservoir (10 mm Ø), situated in the adhesive glue-fabricated hydrophobic zone. Both layers are assembled by a two-sided mounting tape (3.0 mm thickness). The sample is introduced onto the topside reservoir and only Fe (II) reacts specifically with bathophenanthroline (Bphen) to form the stable, red-colored product. Consecutively, the sample flows vertically and exposes the underside reservoir. Then, the PAD is flipped, and the new class of the fluorescein derivative is transferred to the underside reservoir. Fe (III) selectively forms the complex with the fluorophore, and this results in quenching of the green, fluorescent light under UV irradiation. The optical image of each reservoir is captured via a smart phone camera under a light control studio and their color intensities are evaluated by ImageJ™ software. Under the optimal conditions, the calibrations, ranging from 0–0.5 mg L-1 Fe (II) and 0–10 mg L-1 Fe (III) are observed with good linearity (r2 > 0.99). Detection limits (3SD) of 0.02 mg Fe (II) L-1 and 0.21 mg Fe (III) L-1 are achieved. The developed PAD offers good recoveries (94.8–107 %) and high precision (RSD < 4 %). It is also successfully validated against the UV–visible spectrophotometric and the ICP-OES methods. The Fe contents are not significant differences at 95 % confidence under the statistical paired t-test (Fe(II): t<inf>cal</inf> = -0.28, t<inf>cri</inf> = 2.45 and Fe (III): t<inf>cal</inf> = 1.77, t<inf>cri</inf> = 2.45). Remarkedly, The PAD enables the simultaneous determination of Fe(II) and Fe(III) without cross- reactivity effect.
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Simple and fast fabrication of microfluidic paper-based analytical device by contact stamping for multiple-point standard addition assay: Application to direct analysis of urinary creatinine
(2020-04-01)
Mathaweesansurn, Arjnarong
;
Thongrod, Suthathip
;
Khongkaew, Putthiporn
;
Phechkrajang, Chutima Matayatsuk
;
Wilairat, Prapin
In this work, a microfluidic paper-based analytical device (μPAD) for simultaneous multiple-point standard addition assay was fabricated by rubber stamping the hydrophobic barrier pattern onto a laboratory filter paper. The μPAD has a central zone from which an applied sample flows into eight surrounding narrow channels to which had been added the standard solutions. Each channel is connected to a circular area loaded with the reagent. The opposite end of this reagent zone is connected by second narrow channel to the final circular detection zone. The μPAD was applied to the measurement of creatinine in human urine. After addition of a urine sample, the orange-colored product arising from the Jaffé reaction is formed at the eight detection zones. A digital image of the μPAD is then recorded and the ratio of the red/green (R/G) intensity obtained using the ImageJ™ program is used in the quantitation of creatinine. The normal standard addition calibration line is constructed using the intensity ratio against the added creatinine concentrations (50–1000 mg L−1). Good linearity was achieved (r2 ˃ 0.99). There were no significant differences between the creatinine content using an HPLC method (paired t-test at 95% confidence, t<inf>stat</inf> = 1.78, t<inf>critical</inf> = 2.26, n = 10). The use of simultaneous multiple-point standard addition calibration allows rapid determination of creatinine in urine with elimination of matrix interference.

Choengchan, Nathawut

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