Choengchan, Nathawut

Preferred name

Alternative Name

Choengchan, N.

Choengchan, Nuthawut

Main Affiliation

School of Science

nathawut.ch@kmitl.ac.th

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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
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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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Sequential injection for determination of gamma-aminobutyric acid based on its effect on second order light scattering of silver nanoparticles
(2016-08-01)
Jinnarak, Amornrassamee
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Anantavichian, Pattarapon
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Intanin, Apichai
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Fungladda, Suchada
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Choengchan, Nathawut
An automated sequential injection (SI) with second order light scattering (SOS) detection for determination of gamma-aminobutyric acid (GABA) was developed. Quantitation is based on electrostatic interaction between GABA and citrate-capped silver nanoparticles (AgNPs). In acetate buffer at pH 3.8, the positively charged GABA induces the nanoparticles to aggregate. This results in a change of light scattering monitored using a spectrofluorometer. In this work, working standard solutions of GABA were prepared in-line by the SI system pumping appropriate volumes of a stock solution of GABA and acetate buffer into a holding coil. Solution of AgNPs was subsequently drawn into the coil. The reaction zone was then transferred to the spectrofluorometer, set with excitation and detection wavelengths at 300 and 600 nm, respectively. Under optimised condition, the SOS intensity was proportional to the concentration of GABA. As a result, a linear curve was obtained in the range of 100–400 mg L−1 GABA, with a lower limit of detection of 39.6 mg L‐1. Good precision of analysis was achieved, with 0.6 and 3.3% relative standard deviation (RSD) for external calibration (n = 5) and standard addition (n = 3), respectively. The developed method was successfully applied for quantification of GABA in dietary supplements (2 samples) and samples of instant green tea (2 samples).
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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
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Thongrod, Suthathip
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Khongkaew, Putthiporn
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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.
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Foldable paper-based analytical device for membraneless gas-separation and determination of iodate based on fluorescence quenching of gold nanoclusters
(2021-01-01)
Lert-itthiporn, Aurachat
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Srikritsadawong, Pongpichet
;
Choengchan, Nathawut
A new design of a paper-based analytical device (PAD) for membraneless gas-separation with subsequent determination of iodate is presented. The rectangular PAD was invented as the folded pattern, where two circular reservoirs: the donor reservoir and the acceptor reservoir were situated in “a single paper” for convenient use. The hydrophobic barrier of each reservoir was easily fabricated by painting with a permanent marker. The PAD was demonstrated for the quantitative analysis of iodate, based on the fluorescence quenching of the bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs). The BSA-AuNCs were fast prepared by a microwave-assisted approach. The nanoclusters solution was applied into the acceptor reservoir, while the sample, iodide and sulfuric acid were sequentially aliquoted into the donor reservoir. After folding the PAD, the donor and the acceptor were mounted together via a two-sided mounting tape. The headspace between the two reservoirs allows membraneless gas-separation of free iodine from the donor to diffuse into the acceptor. Etching of gold core of the nanoclusters in the acceptor resulted in quenching of the red emission, was monitored by two methods, i.e. “fluorometric detection” (λ<inf>ex</inf>: 490 nm, λ<inf>em</inf>: 630 nm) and “image capture” of the acceptor under the UV irradiation by a smart phone's camera. Two calibrations were plotted accordingly to their detections and good linearities (r2 ˃ 0.98) were observed from 0.005 to 0.1 mmol L−1 iodate. High accuracy (mean recovery: 95.1 (±4.6) %) and high precision (RSD < 3%) were obtained. The lower limits of detection were 0.005 mmol L−1 (with fluorometric detection) and 0.01 mmol L−1 (with image capture). The method was effectively applied for the measurement of iodate in iodized salts and fish sauces without prior sample pre-treatment.
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Development of a Tannic Acid-Gelatin Modified Filter Paper Membrane for Trace Lead Detection in Water
(2026-06-16)
Rattanadechawan, Arinrada
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Choengchan, Nathawut
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Mantim, Thitirat
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Donpudsa, Suchao
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Karuwan, Chanpen
A novel membrane-based solid-phase extraction (SPE) device was developed using cellulose filter paper modified with a tannic acid–gelatin (TA/GE) composite for the preconcentration of lead (Pb(II)) ions from aqueous samples. The TA/GE sorbent layer was fabricated via cross-linking gelatin with tannic acid at pH 9, forming a stable, partially insoluble network that enhances the membrane’s mechanical strength and ion-binding capability. Characterization by SEM confirmed the successful modification, while micro-XRF analysis demonstrated the membrane’s effective adsorption and elution of Pb(II). After preconcentration, square wave anodic stripping voltammetry (SWASV) was used for quantitative determination. The method exhibited linear range of 10–100 μg·L–1, with a limit of detection (LOD) of 2.7 μg·L–1. Method validation using a certified reference material for trace metals in water produced a combined measurement uncertainty (U) of 9 μg·L–1 at the 95% confidence level for a sample containing 61 μg·L–1 Pb(II), showing no significant deviation from the certified value. The developed method was further applied to drinking water and river water samples, achieving recoveries of 82–110% for spiked samples. These results confirm that the TA/GE-modified membrane provides a simple, low-cost, and environmentally friendly platform for trace Pb(II) analysis, with performance meeting both WHO (10 μg·L–1) and Thailand Pollution Control Department (50 μg·L–1) regulatory standards for drinking and surface water.
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Preparation of gold nanoparticles-bacterial cellulose nanopaper and its application as 2D-microcuvette for spectrophotometric determination of hydrogen peroxide
(2021-01-01)
Lert-Itthiporn, Aurachat
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Phunpruch, Saranya
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Prommajun, Munlika
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Srikritsadawong, Pongpichet
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Choengchan, Nathawut
This work presents a new method development using the gold nanoparticles (AuNPs)-bacterial cellulose (BC) nanopaper for the spectrophotometric determination of hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>). The AuNPs were embedded in the BC nanopaper, where the nanopaper played two roles as both the reducing agent and the template for the as-prepared AuNPs. The preparation process was started by putting the wet bare BC nanopaper (Ø 30 mm and 3 mm thickness) into 0.75 mmol L-1 HAuCl<inf>4</inf> (25.0 mL). This solution was vigorously and continuously stirred for 60 min at 90ºC. After the embedding process, color of the nanopaper was changed from milky-white to wine-red. The AuNPs-BC nanopaper was characterized by UV-visible spectrophotometer, FE-SEM and EDS. Absorption spectrum of the nanopaper showed the characteristic peak of Au0 at 525 nm. The amount of 97.3 weight % of Au0 was found. The spectrophotometric assay was carried out by dropping the aliquots of 100 µL of sample and 400 µL of 20 mmol L-1 citrate buffer (pH 6.0) onto the AuNPs-BC nanopaper. The nanopaper was then kept in a plastic back for 10 min. In the presence of H<inf>2</inf>O<inf>2</inf>, the wine-red color of the AuNPs-BC nanopaper was turned to pale red accordingly to reduction of Auo to Au(III) by H<inf>2</inf>O<inf>2</inf>. Decreasing in the absorbance of the nanopaper at 525 nm was monitored using UV-visible spectrophotometer. Detection limit (y<inf>B</inf> + 3S<inf>B</inf>) of 0.79 % (v/v) was observed and this value was enough sensitive for the determination of H<inf>2</inf>O<inf>2</inf> in wound cleaner and hair dye samples. The H<inf>2</inf>O<inf>2</inf> contents in all samples were agreed well with the label values. Good analytical recovery (88.8 to 97.2 %) with high precision (RSD: 3.3 %) were obtained. These results confirmed that the as-prepared nanopaper was successfully synthesized and was effectively applied as the two dimensional (2D)-microcuvette for the spectrophotometric determination of H<inf>2</inf>O<inf>2</inf> in real samples.
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Tandem measurements of iron and creatinine by cross injection analysis with application to urine from thalassemic patients
(2015-01-01)
Choengchan, N.
;
Mantim, T.
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Inpota, P.
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Nacapricha, D.
;
Wilairat, P.
This work presents development of a method for the dual determination of Fe(III) and creatinine using cross injection analysis (CIA). Two CIA platforms connected in series accommodated sample and reagents plugs aspirated via y-direction channels while water was pumped through the x-direction channel toward a flow-through cell of a diode array UV-vis. detector. Iron was detected from the colorimetric reaction between Fe(II) and 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N-(3-sulfopropyl)amino) aniline (5-Br-PSAA), with prior reduction of Fe(III) to Fe(II) by ascorbic acid. The Jaffes reaction was employed for the detection of creatinine. Under the optimal conditions, good linearity ranges were achieved for iron in the range 0.5 to 7 mg L-1 and creatinine in the range 50 to 800 mg L-1. The CIA system was applied to spot urine samples from thalassemic patients undergoing iron chelation therapy, and was successfully validated with ICP-OES and batchwise Jaffes method. Normalization of urinary iron excretion with creatinine is useful for correcting the iron concentration between urine samples due to variation of the collected urine volume.
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Chemometrics-assisted cross injection analysis for simultaneous determination of phosphate and silicate
(2016-07-14)
Uraisin, Kanchana
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Janya, Supavita
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Phechkrajang, Chutima
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Choengchan, Nathawut
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Tiyapongpattana, Warawut
This work presents a novel method for simultaneous spectrophotometric determination of phosphate and silicate by using a cross injection analysis (CIA) coupled with the use of partial least squares (PLS) for data evaluation. The detection principle is based on the well-known ‘molybdenum blue’ method. The molybdate ions in the presence of stannous chloride in acidic medium give phosphomolybdenum blue and silicomolybdenum blue as products. In this work, all the liquids, including sample and reagents were simultaneously introduced into a CIA platform by using two peristaltic pumps for controlling the x-channel and y-channel flow which was automatically manipulated by using in-house control board. Crossflow provides sufficient mixing inside the platform prior detection of the absorption spectra of blue complexes in the wavelength of 400–900 nm. Since spectra of the blue colour product of phosphate and silicate are resemblant, these two analytes therefore reciprocally interfere with one another. This results in difficulty in simultaneous analysis of phosphate and silicate. In this work, PLS was utilised as assistor of CIA system for simultaneous analysis of phosphate and silicate using molybdenum blue reaction without using any modification of reagents and addition of selective masking agent. The calibration ranges are 0.1–6 mgP L−1 and 5–100 mgSi L−1 for phosphate and silicate, respectively. By using CIA coupled with PLS for data evaluation, the analysis of two analytes was achieved within 1.5 min with only single injection. The developed system was applied to natural water samples and the system was validated with the conventional methods. By statistical paired t-test, there was no evidence of significant difference at 95% confidence level (t<inf>stat</inf> = 2.28, t<inf>critical</inf> = 2.31 and t<inf>stat</inf> = 0.62, t<inf>critical</inf> = 2.31 for phosphate and silicate, respectively). This implied that the chemometrics-assisted CIA system was successfully developed for simultaneous spectrophotometric determination of phosphate and silicate.
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Quality control of gasohol using a micro-unit for membraneless gas diffusion
(2009-01-01)
Muncharoen, Sasithorn
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Sitanurak, Jirayu
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Tiyapongpattana, Warawut
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Choengchan, Nathawut
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Ratanawimarnwong, Nuanlaor
This work describes the development of a new spectrophotometric flow technique suitable for monitoring of ethanol content in gasohol fuel. Membraneless gas-diffusion (MBL-GD) was applied with one-step aqueous extraction of gasohol (1:2 gasohol/water). Segments of aqueous extract and color developing reagent were allowed to flow into two separate channels in the MBL-GD device. Inside the device, ethanol vapor can diffuse across a small headspace between the two channels (donor and acceptor). Introduction of an air-segment behind the zone of acceptor reagent to stop dispersion of the colored zone greatly improves the rapidity of analysis using this MBL-GD technique. Two methods were developed for quality control of gasohol by measuring ethanol content. Method I is suitable for direct calibration of E5 and E10. Method II is recommended for E20. These methods have high accuracy with good precision (% RSD: 1 to 4.9, n=45) and have a sample throughput of 26 samples per hour. E10 samples were compared with analysis using a standard GC method. © 2008 Springer-Verlag.
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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
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Choengchan, Nathawut
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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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Choengchan, Nathawut

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