In the present study, multiwalled carbon nanotubes（MWCNTs）, gold nanoparticles（AuN Ps）, and glutathione（GSH） were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by la...In the present study, multiwalled carbon nanotubes（MWCNTs）, gold nanoparticles（AuN Ps）, and glutathione（GSH） were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly（diallydimethylammonium chloride） to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl_4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuN Ps. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 mmol/L. The limits of detection and quantitation of dopamine are（0.316 ± 0.081） mmol/L and（1.054 ± 0.081） mmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.展开更多
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 depo...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 rim, 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 samt）les.展开更多
基金financially supported by the Faculty of Science,King Mongkut’s Institute of Technology Ladkrabang,Bangkok,Thailand(No.2558-02050067)
文摘In the present study, multiwalled carbon nanotubes（MWCNTs）, gold nanoparticles（AuN Ps）, and glutathione（GSH） were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly（diallydimethylammonium chloride） to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl_4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuN Ps. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 mmol/L. The limits of detection and quantitation of dopamine are（0.316 ± 0.081） mmol/L and（1.054 ± 0.081） mmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.
基金supported by Faculty of Science,King Mongkut's Institute of Technology Ladkrabang,Bangkok,Thailand(No.2559-01-05-033)
文摘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 rim, 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 samt）les.
