Detsri, Ekarat
Loading...
7 results
Now showing 1 - 7 of 7
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, A sensitive and selective colorimetric sensor for reduced glutathione detection based on silver triangular nanoplates conjugated with gallic acid(2018-03-20); ; Silver triangular nanoplates conjugated with gallic acid (AgTNPs⋅GA) was designed and synthesized for colorimetric detection of reduced glutathione (GSH). The surface plasmon resonance (SPR) properties of AgTNPs⋅GA were strongly influenced by the addition of GSH. The detection principle was based on the aggregation of AgTNPs⋅GA, which leads to the significant bathochromic shift of the SPR spectra from 602 nm to 650 nm. The dramatic color changes from the initial dark blue to light blue can be observed, which allowed simple monitoring of GSH ether by naked eye and UV–vis spectrophotometer. With UV–vis spectrophotometer measurements, a quantitative linearity was established in the range of 0.5–5.0 nM (R<sup>2</sup> = 0.9919) and with a limit of detection (LOD) of 0.12 ± 0.02 nM. Relative standard deviation (RSD) of 3.46% and 1.82% (n = 10) were achieved for the determination of 1.0 and 3.0 nM, respectively. No interfering substances such as ascorbic acid, glucose, sucrose, citric acid, cysteine, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Fe<sup>3+</sup> and K<sup>+</sup> were revealed in the AgTNPs⋅GA based assay. The proposed colorimetric strategy could be extended as the general platform for detection of GSH in dietary supplements and no significant differences in accuracy and precision were observed compared to HPLC standard method. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Aggregated gallic acid-modified platinum nanoparticles as colorimetric sensor for tannic acid detection in beverages based on displacement phenomenon(2024-10-01); ; A new colorimetric assay for the rapid detection of tannic acid in beverage samples based on displacement phenomenon of aggregated gallic acid-modified platinum nanoparticles is developed for the first time. PtNPs were functionalized with gallic acid, promoting the formation of the green-hued aggregated nanoparticles. While colorimetry offers a rapid method for identifying tannic acid, challenges remain in sensitivity and accuracy of detection on the PtNPs colorimetric probe, particularly in the presence of anthocyanin interferences. To address this, we developed a sample preparation method to degrade anthocyanin in beverages. Tannic acid was easily displaced onto the gallic acid-coated PtNPs surfaces, causing dispersion and resulting in a visible color change from green to orange − brown. Under the optimal conditions, the colorimetric sensor exhibited a linear response in the range of 1 − 2,000 µmol/L (R<sup>2</sup> = 0.9991). The limit of detection (LOD) and the limit of quantification (LOQ) were found at 0.02 and 0.09 µmol/L, respectively. The proposed sensor expressed superior selectivity over other interfering substances and demonstrated excellent precision with a relative standard deviation (RSD) of 1.00 %−3.36 %. More importantly, recoveries ranging from 95.0 − 104.7 % were obtained, indicating the capability of proposed colorimetric sensor to detect tannic acid rapidly and accurately in real beverage samples. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Microwave-assisted synthesis of unmodified gold nanoparticles for colorimetric detection of dopamine(2017-01-01); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A new colorimetric method for determination of formaldehyde in sea food based on anti-aggregation of gold nanoparticles(2022-12-01); A new colorimetric method based on anti-aggregation of gold nanoparticles (AuNPs) in the presence of melamine for sensitive and selective determination of formaldehyde was developed. The citrate capped AuNPs was synthesized by Turkevich method. A certain concentration of melamine is responsible for color change of AuNPs from red to purple. The surface plasmon resonance peak was shifted from 520 to 640 nm. In the presence of formaldehyde, the reaction between melamine and formaldehyde to form methylol melamine was occurred, which resulted in the decreasing of aggregation of AuNPs. Based on the anti-aggregation mechanism, formaldehyde can be detected by observing the color change of AuNPs solution containing melamine, which was monitored by UV–visible spectrophotometer. Calibration curve plotted between absorbance ratio (A640/A520) and formaldehyde concentration was made with linearity of 0 – 2000 µg L<sup>−1</sup>. The limit of detection and the limit of quantitation were found at 26.0 µg L<sup>−1</sup> and 88.0 µg L<sup>−1</sup>, respectively. The method also provided high accuracy (%recovery in range 97.3 – 104%) and high precision (%RSD < 5.6). - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Novel colorimetric sensor for mercury (II) based on layer-by-layer assembly of unmodified silver triangular nanoplates(2016-10-01)A simple layer-by-layer deposition technique was used to fabricate the multilayer thin films of unmodified silver triangular nanoplates (AgTNPs). The multilayer of AgTNPs thin films were fabricated by alternate deposition of each anionic sodium citrate stabilized AgTNPs and cationic poly(diallyldimethylammonium chloride). All prepared AgTNPs multilayer thin films were exhibited a strong plasmon band at the wavelength of 667 nm, which confirmed the formation of AgTNPs onto the substrate. The characteristics of the multilayer thin films were investigated using contact angle measurement, UV–visible spectroscopy, X-ray diffraction analysis (XRD), atomic force microscope (AFM) and field emission scanning electron microscope (FESEM). As these films are to be used as a mercury (II) colorimetric sensor, the changes in optical properties of the films were evaluated for various mercury (II) concentrations. AgTNPs assembled into thin films showed a strong color shift from blue to mauve and colorless when exposed to mercury (II). The constructed multilayer thin films exhibited excellent color changes of mercury (II) with a linear range between 0.5 and 20 ppm. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.45 ± 0.002 and 1.52 ± 0.002 ppm, respectively. The recovery values of AgTNPs multilayer thin films are satisfactory in the range of 100.1%–106.4% when applied to determining mercury (II) in water samples. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Highly sensitive and selective colorimetric sensor of mercury (II) based on layer–by–layer deposition of gold/silver bimetallic nanoparticles(2020-10-01); ; A new colorimetric sensor based on gold/silver bimetallic nanoparticles (Au–Ag BNPs) for the sensitive and selective detection of mercury (II) was developed. Gold nanoparticles (AuNPs) were synthesized by Turkevich method. The surface modification of AuNPs was modified by the layer–by–layer technique using poly(diallyl dimethylammonium chloride) which provided positively charged of AuNPs. Negatively charged silver nanoparticles (AgNPs) were synthesized by chemical reduction using poly(4–styrenesulfonic acid–co–maleic acid) as the stabilizing agent. The layer–by–layer assembly deposition technique was used to prepare Au–Ag BNPs of positively and negatively charged of AuNPs and AgNPs, respectively. The synthesized Au–Ag BNPs were characterized by a UV-visible spectrophotometer, zeta potential analyzer, FT–IR, TEM, XRD, and EDX. The Au–Ag BNPs sensor was able to detect mercury (II) in aqueous solution, visibly changing from brownish–orange to purple. The linear relationships of the UV-visible spectrometry demonstrate that the Au–Ag BNPs-based colorimetric sensor can be used for the quantitative analysis of mercury (II) in the range of 0.5–80 mg L<sup>−1</sup>, with the correlation coefficient, r<sup>2</sup> = 0.9818. The limit of detection (LOD) of mercury (II) was found to be 0.526 + 0.001 mg L<sup>−1</sup>. The BNPs is also verified to have a good practical applicability for mercury (II) detection in the real samples. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Colorimetric detection of glutathione based on phthalic acid assisted synthesis of silver nanoparticles(2017-11-20); A new rapid, sensitive and selective colorimetric sensing platform for the detection of glutathione (GSH) in dietary supplements was developed by phthalic acid (PTA) assisted synthesis of silver nanoparticles (AgNPs). The di-carboxylic functional groups of PTA were used to modify the surface of AgNPs. The resulting AgNPs product was characterized by surface plasmon resonance (SPR) Ultraviolet–visible spectroscopy (UV–vis), Zeta potential analyzer, Fourietransform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD) techniques, demonstrated that PTA is an effective capping agent to stabilize AgNPs. AgNPs stabilized with PTA could cause the strong affinity to GSH. As the GSH concentration increased, the color of AgNPs solutions was gradually changed from yellow to orange and light purple as well as the SPR shifted from 400 nm to 556 nm upon an aggregation of AgNPs due to electrostatic interaction. The proposed colorimetric sensor was exhibited a linear response in the range of 0.1–100 nM (R<sup>2</sup> = 0.9992), with low detection limit (LOD) of 0.16 ± 0.01 nM. The sensor showed better precision with relative standard deviation (RSD) of 2.10% and 1.13% for ten repetitive measurements of 25 nM and 75 nM GSH solution, respectively. The sensitivity of AgNPs for GSH detection can be clearly differentiated towards other coexisting substances (Fe<sup>3+</sup>, Zn<sup>2+</sup>, Cu<sup>2+</sup>, K<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, glucose, sucrose, cysteine, ascorbic acid and citric acid). The AgNPs colorimetric sensor could discriminatively detect GSH in dietary supplement samples with the recoveries values in the range of 98.5%–103.0%.