Bentonvogel6955

In this study, a novel, simple and sensitive ratiometric fluorescence method is presented for the detection of very low quantities of the carbaryl in Iranian apple using cadmium telluride quantum dots (CdTe QDs) nanoprobe. The principle of the proposed strategy relies on the rapid hydrolysis of the carbaryl under an alkaline condition and production of the 1-naphthol with a blue emission at 470 nm. Besides, using the CdTe QDs with a yellow emission at 580 nm, as a reference, improves the visual tracking of carbaryl through changes in color tonality. The herein described methodology is applied for enzyme-free visual detection of carbaryl with satisfactory results in the presence of other common pesticides in Iranian apple sample. Additionally, the calculated limit of detection (LOD) of 0.12 ng mL-1 for carbaryl is much lower than the maximum residue limits of carbaryl warned value reported by the European Union and United States pesticides database, which is so promising for carbaryl sensing in the monitoring of fruits. Furthermore, the ability of the proposed method for the detection of carbaryl residues in Iranian apple was confirmed by the high-performance liquid chromatography (HPLC) method as a standard method through statistical analysis. This fast and highly sensitive naked-eye ratiometric sensor may hold great promise to provide the technical support for the rapid and valid detection of other targets in food safety fields.Robust quantitative analysis methods are very attractive but challenging with surface-enhanced Raman scattering (SERS) technique till now. Quantitative analysis methods using absolute Raman scattering intensities tend to desire very critical reproducibility of SERS substrates and consistency of testing conditions, as batch differences and inhomogeneity of SERS substrates as well as the fluctuation of measuring parameters placed challenging obstacles. Relative Raman scattering intensities, on the other hand, can release the adverse interferences mentioned above and provide effective and robust information as it is independent of the reproducibility of SERS substrates. By establishing external calibration working curves, we achieved accurate molecule composition prediction of molecules in multi-component systems. Further, by choosing or adding a label molecule with known concentration as Raman internal standards, the concentration of target molecules can be easily predicted. Revumenib This approach proved the effectiveness and robustness of quantitative analysis with the relative Raman scattering intensities, even carried out with a flexible inhomogeneous SERS substrate.A sandwich temperature control membrane inlet system based on a miniature mass spectrometer is presented that demonstrates improved analytical performance for the measurement of dissolved gases and volatile organic compounds (VOCs) in aqueous solution. Aqueous solution is directly brought to the monolayer flat membrane interface at a constant flow rate. A heating resistor and a thermocouple are fixed on the side of the membrane and aqueous solution respectively. This new strategy allows for a temperature compensation method, affording an improvement of sensitivity and a reduction of response time compared with the conventional heating solution temperature control strategy. Furthermore, a static heating mode is applied to effectively remove the memory effect. Automatic sampling and measurement are achieved by using the membrane inlet system with silicone sheeting of 50 μm thickness. The vacuum is below 3 × 10-5 Torr, which can make the instrument work normally. A good linear response is observed for benzene in the range of 0.1 ppm-10 ppm and the detection limit is 50 ppb. The analytical capacity of this system is demonstrated by the on-line analysis of VOCs in aqueous solution, in which the dominant ions are detected rapidly. The results indicate that the sandwich temperature control membrane inlet mass spectrometer (STC-MIMS) has a potential application for on-line analyzing organic pollution in aquatic environments.In this study, we describe the construction of an "off-on" fluorescent probe based on carbon dots (CDs) and silver nanoparticles (AgNPs) mixture for sensitive and selective detection of cysteamine. By mixing AgNPs with CDs solution, the fluorescence of CDs was significantly decreased due to the inner filter effect (IFE). Upon addition of cysteamine to the mixed aqueous of CDs and AgNPs, the silver-sulfur bond between cysteamine and AgNPs caused AgNPs to aggregate, and the quenched fluorescence of CDs could in turn be recovered. The probe was employed to quantitatively detect cysteamine, and the results showed that it could detect cysteamine in a concentration range of 2-16 μM with the detection limit of 0.35 μM (signal-to-noise ratio of 3). The detection of cysteamine spiked into bovine serum samples showed high recovery rates ranging from 95.5 to 111.7%. More importantly, the developed probe had low cytotoxicity and was successfully used for in vivo imaging of HepG2 cells.Sexually transmitted infections are a serious public health concern worldwide, especially in young people. More than 30 pathogens can cause sexually transmitted diseases and co-infection often occurs. Therefore, the development of fast, low-cost and easy-to-use diagnostic screening methods is urgently needed for disease prevention and control. Herein, we established an all-in-one microfluidic nucleic acid diagnosis system, which could simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis and Ureaplasma urealyticum directly from genitourinary secretions with minimal manual manipulations. This system integrated nucleic acid extraction, amplification, and detection on a single microfluidic chip and could be automatically performed in an integrated detection device. This novel diagnosis tool showed good detection limits, stability (coefficient of variation less then 6%), specificity (no cross-reaction with 23 other pathogens for each target) and resistance to interference by other substances and the diagnostic efficacy was similar to that of PCR. The turn-around time was reduced to 50 min from sample to answer with automated testing steps. This novel diagnosis tool has the advantages of highly integrated, automated, sample-to-answer detection, and could thus replace the traditional method. This could significantly improve the prevention and control of sexually transmitted diseases.