tellurium and tetraethoxysilane

A dual recognition system with a fluorescence quenching of quantum dots (QDs) and specific recognition of molecularly imprinted polymer (MIP) for the detection of chloramphenicol (CAP) was constructed. MIP@SiO

Topics: Cadmium Compounds; Chloramphenicol; Fluorescence; Fluorometry; Hydrogen-Ion Concentration; Lakes; Limit of Detection; Microscopy, Electron, Transmission; Molecular Imprinting; Propylamines; Quantum Dots; Sensitivity and Specificity; Silanes; Silicon Dioxide; Spectroscopy, Fourier Transform Infrared; Tellurium; Water Pollutants, Chemical

To ensure food safety and to prevent unnecessary foodborne complications this study reports fast, fully automated process for histamine determination. This method is based on magnetic separation of histamine with magnetic particles and quantification by the fluorescence intensity change of MSA modified CdSe Quantum dots. Formation of Fe

Topics: Cadmium Compounds; Ferric Compounds; Fluorescence; Fluorescent Dyes; Food Contamination; Histamine; Limit of Detection; Magnetic Phenomena; Metal Nanoparticles; Quantum Dots; Silanes; Spectrometry, Fluorescence; Tellurium; Titanium; Wine

A molecularly imprinted polymer (MIP) anchored on the surface of CdTe quantum dots (QDs) was fabricated and used as a fluorescent probe for sulfadiazine (SDZ) detection in seawater. CdTe QDs was used as photoluminescent material, SDZ as the template, 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethyl orthosilicate (TEOS) as the cross-linking agent. Characterizations of MIP-QDs were analyzed by Fourier transform infrared (FT-IR), Transmission electron microscopy (TEM) and Scanning electron microscope (SEM). The conditions were optimized for the detection of MIP-QDs to SDZ. The mechanism of fluorescence quenching was studied by UV-Vis absorption spectroscopy and fluorescence spectroscopy. Under optimal conditions, the fluorescence intensity of MIP-QDs decreased linearly between 4- and 20 μM SDZ with a good correlation coefficient of 0.995. The limit of detection is 0.67 μM and the recovery is between 91.8 and 109.4% with RSD lower than 3.9%. These results indicated that MIP-QDs for SDZ detection in seawater was developed successfully.

Topics: Anti-Bacterial Agents; Cadmium Compounds; Fluorescent Dyes; Limit of Detection; Microscopy, Electron, Transmission; Molecular Imprinting; Polymers; Propylamines; Quantum Dots; Seawater; Silanes; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Sulfadiazine; Tellurium; Water Pollutants, Chemical

A novel procedure for the optosensing of clenbuterol and melamine was developed using molecularly imprinted polymer-capped CdTe quantum dots (MIP-CdTe QDs). The MIP-CdTe QDs were synthesized by a radical polymerization process among CdTe QDs, a template, 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS). The sizes of the MIP-CdTe particles were controlled by the speed of polymerization, concentration of the template, concentration of the quantum dots, and the ratio of template, monomer and cross-linker. Excellent selectivity and high sensitivity of MIP-CdTe QDs toward clenbuterol/melamine molecules were observed based on the fluorescence quenching of QDs. Experimental results showed that the optimum molar ratios of template, monomer, and cross-linker were 1:8:20 and 1:4:20 for analyzing clenbuterol and melamine, respectively. Under optimum conditions, these MIP-CdTe QDs showed a limit of detection of 0.4 μM (120 ng/mL) for clenbuterol and 0.6 μM (75 ng/mL) for melamine. The feasibility of the developed method in real samples was successfully evaluated through the analysis of clenbuterol and melamine in milk and liver samples with satisfactory recoveries of 92-97%. The MIP-CdTe QDs could be easily regenerated for subsequent sample analysis with water.

Topics: Adrenergic beta-Agonists; Animals; Biosensing Techniques; Cadmium Compounds; Clenbuterol; Food Contamination; Limit of Detection; Milk; Molecular Imprinting; Propylamines; Quantum Dots; Silanes; Tellurium; Triazines