Well-dispersed CdS quantum dots (QDs) with narrow size-distribution were prepared using generation 4.5 ester-terminated PAMAM dendrimers as inner-templates. The average diameter of CdS QDs was 1.5 nm and the photolumi...Well-dispersed CdS quantum dots (QDs) with narrow size-distribution were prepared using generation 4.5 ester-terminated PAMAM dendrimers as inner-templates. The average diameter of CdS QDs was 1.5 nm and the photoluminescence was purple. The room temperature photoluminescence quantum yield (RT-PQY) was 0.015. The diameter of CdS QDs increased with the increase of n / nPAMAM, also the color of photoluminescence was tunable and could be changed from purple to blue.展开更多
A photoelectrochemical immunosensor based on multi-electrode array was developed for simultaneous and sen- sitive determination of veterinary drug residues. In this system, poly（dimethyldiallylammonium chloride） （P...A photoelectrochemical immunosensor based on multi-electrode array was developed for simultaneous and sen- sitive determination of veterinary drug residues. In this system, poly（dimethyldiallylammonium chloride） （PDDA）, Au nanoparticles （Au NPs） and thioglycolic acid （TGA）-capped CdS quantum dots （QDs） were layer-by-layer as- sembled onto the home-made Au electrode array. The assembling process of the （CdS/PDDA/Au NPs/PDDA）, mul- tilayer was characterized by electrochemical impedance spectroscopy. And then the antibodies for clenbuterol （CB）, ractopamine （RAC） and chloramphenicol （CAP） were covalently immobilized onto the Au electrode array by 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide （EDC） coupling reaction, respectively. The concentrations of CB, RAC and CAP were measured based on the photoelectrochemical effects of CdS QDs. Under the optimal conditions the limits of detection （LOD） for CB, RAC and CAP were 25, 50 and 2.2 pg/mL （3a）, respectively, with acceptable recovery over the range of 95.40%--105.5% in pig liver samples. All results indicate that the immunosensor array system has potential application for practical, effective and high throughput analysis of veterinary drugs residues.展开更多
Water-soluble CdS quantum dots（CdS-QDs） capped with thioglycohc acid were easily prepared, and a detection method of adriamycin was presented based on the fluorescence quenching of CdS-QDs. It was found that a compl...Water-soluble CdS quantum dots（CdS-QDs） capped with thioglycohc acid were easily prepared, and a detection method of adriamycin was presented based on the fluorescence quenching of CdS-QDs. It was found that a complex could be formed between cetyhrimethyl ammonium bromide（CTAB） and CdS-QDs by using electrostatic interaction in Britton-Robinson（BR） buffer at pH = 7.00, and the strong fluorescence emission of the complex was observed at 500 nm when the complex was excited at 378 run. The presence of adriamycin, however, could strongly quench the fluorescence through hydrophobic interaction. The overall quenching percentage as a function of adriamycin concentration matches the Stern-Volmer equation very well. These properties make CdS-QDs a potential fluorescence probe for the detection of adriamycin. The detection hmit（3σ） of adriamycin is approximately 10^-9 mol/L.展开更多
Nanocrystalline CdS thin films have been deposited using precursors with different thiourea concentrationonto glass substrates by sol-gel spin coating method.The crystalline nature of the films has been observedto be ...Nanocrystalline CdS thin films have been deposited using precursors with different thiourea concentrationonto glass substrates by sol-gel spin coating method.The crystalline nature of the films has been observedto be strongly dependent on thiourea concentration and annealing temperature.The CdS films are found tobe nanocrystalline in nature with hexagonal structure.The grain size is found to be in the range of 7.6 to11.5 nm depending on the thiourea concentration and annealing temperature.The high resolution transmissionelectron microscopy （HRTEM） results of the CdS films prepared using cadmium to thiourea molar ratio of0.3：0.3 indicate the formation of nanocrystalline CdS with grain size of 5 nm.Fourier transform infrared （FTIR）analysis shows the absorption bands corresponding to Cd and S.The optical study carried out to determinethe band gap of the nanostructured CdS thin films shows a strong blue shift.The band gap energy has beenobserved to lie in the range of 3.97 to 3.62 eV following closely the quantum confinement dependence ofenergy on crystallite radius.The dependence of band gap of the CdS films on the annealing temperature andthiourea concentration has also been studied.The photoluminescence （PL） spectra display two main emissionpeaks corresponding to the blue and green emissions of CdS.展开更多
文摘Well-dispersed CdS quantum dots (QDs) with narrow size-distribution were prepared using generation 4.5 ester-terminated PAMAM dendrimers as inner-templates. The average diameter of CdS QDs was 1.5 nm and the photoluminescence was purple. The room temperature photoluminescence quantum yield (RT-PQY) was 0.015. The diameter of CdS QDs increased with the increase of n / nPAMAM, also the color of photoluminescence was tunable and could be changed from purple to blue.
文摘A photoelectrochemical immunosensor based on multi-electrode array was developed for simultaneous and sen- sitive determination of veterinary drug residues. In this system, poly（dimethyldiallylammonium chloride） （PDDA）, Au nanoparticles （Au NPs） and thioglycolic acid （TGA）-capped CdS quantum dots （QDs） were layer-by-layer as- sembled onto the home-made Au electrode array. The assembling process of the （CdS/PDDA/Au NPs/PDDA）, mul- tilayer was characterized by electrochemical impedance spectroscopy. And then the antibodies for clenbuterol （CB）, ractopamine （RAC） and chloramphenicol （CAP） were covalently immobilized onto the Au electrode array by 1-ethyl-3-（3-dimethylaminopropyl） carbodiimide （EDC） coupling reaction, respectively. The concentrations of CB, RAC and CAP were measured based on the photoelectrochemical effects of CdS QDs. Under the optimal conditions the limits of detection （LOD） for CB, RAC and CAP were 25, 50 and 2.2 pg/mL （3a）, respectively, with acceptable recovery over the range of 95.40%--105.5% in pig liver samples. All results indicate that the immunosensor array system has potential application for practical, effective and high throughput analysis of veterinary drugs residues.
基金the National Natural Science Foundation of China(No 30570465) the Municipal Science and Technology Committee of Chongqing
文摘Water-soluble CdS quantum dots（CdS-QDs） capped with thioglycohc acid were easily prepared, and a detection method of adriamycin was presented based on the fluorescence quenching of CdS-QDs. It was found that a complex could be formed between cetyhrimethyl ammonium bromide（CTAB） and CdS-QDs by using electrostatic interaction in Britton-Robinson（BR） buffer at pH = 7.00, and the strong fluorescence emission of the complex was observed at 500 nm when the complex was excited at 378 run. The presence of adriamycin, however, could strongly quench the fluorescence through hydrophobic interaction. The overall quenching percentage as a function of adriamycin concentration matches the Stern-Volmer equation very well. These properties make CdS-QDs a potential fluorescence probe for the detection of adriamycin. The detection hmit（3σ） of adriamycin is approximately 10^-9 mol/L.
文摘Nanocrystalline CdS thin films have been deposited using precursors with different thiourea concentrationonto glass substrates by sol-gel spin coating method.The crystalline nature of the films has been observedto be strongly dependent on thiourea concentration and annealing temperature.The CdS films are found tobe nanocrystalline in nature with hexagonal structure.The grain size is found to be in the range of 7.6 to11.5 nm depending on the thiourea concentration and annealing temperature.The high resolution transmissionelectron microscopy （HRTEM） results of the CdS films prepared using cadmium to thiourea molar ratio of0.3：0.3 indicate the formation of nanocrystalline CdS with grain size of 5 nm.Fourier transform infrared （FTIR）analysis shows the absorption bands corresponding to Cd and S.The optical study carried out to determinethe band gap of the nanostructured CdS thin films shows a strong blue shift.The band gap energy has beenobserved to lie in the range of 3.97 to 3.62 eV following closely the quantum confinement dependence ofenergy on crystallite radius.The dependence of band gap of the CdS films on the annealing temperature andthiourea concentration has also been studied.The photoluminescence （PL） spectra display two main emissionpeaks corresponding to the blue and green emissions of CdS.
