A highly sensitive resonance Rayleigh scattering and colorimetric assay for the recognition of propranolol in β‐adrenergic blocker

Recognition of chiral propranolol by fluorescent aptamerlight switch based on GO

In this work, specific aptamers with affinity for S-propranolol were screened by SELEX technology based on the graphene oxide (GO) adsorption platform, and a GO-FAM labeled aptamer-propranolol fluorescent optical switch system was constructed for the recognition of chiral propranolol. It was found that the fluorescence quenching of FAM labeled aptamer could be caused by the adsorption of GO. However, when S-propranolol was introduced, S-propranolol could pull out the aptamer adsorbed by GO, and the fluorescence of the system could be restored. But, R-propranolol could not be realized. Therefore, a simple and sensitive fluorescent optical switch system was established to identify chiral propranolol and perform highly sensitive detection of S-propranolol.

New Ag-Doped COF Catalytic Amplification Aptamer Analytical Platform for Trace Small Molecules with the Resonance Rayleigh Scattering Technique

Covalent organic frameworks (COFs) and Ag-doped COFs (AgCOFs) are prepared by the polycondensation procedure and characterized by electron microscopy and molecular spectral techniques. Their catalysis of the Cu₂O particle reaction of glucose (GL)-Cu(II) was examined by resonance Rayleigh scattering (RRS), and AgCOFs were found to exhibit the strongest catalysis. The melamine (ML) aptamers (Apt_ML) can attach to the surface of AgCOF and inhibit its catalytic activity. When melamine (ML) is added to this reacting solution, Apt_ML-ML complexes are formed and the Apts are desorbed from the surface of AgCOF. As the concentration of ML increased, the catalytic activity of AgCOF increased and the RRS signal enhanced due to the increase in Cu₂O particles. When the ML concentration was in the range of 0.79-13.2 nmol/L, the RRS intensity increased linearly, with a detection limit of 0.72 nmol/L. When the Apts of urea and bisphenol A (BPA) were replaced by the Apt_ML, 66.7-1333 nmol/L urea and 0.33-2.7 nmol/L BPA, respectively, could also be determined, with detection limits of 30.4 nmol/L urea and 0.15 nmol/L BPA. Based on this, a new AgCOF amplification RRS method was established.

A novel spectral method for determination of trace malathion using EryB as light scattering probe by resonance Rayleigh scattering technique

A convenient and sensitive spectrophotometric methods was proposed for determination of Malathion (Mala) using Erythrosin B (EryB) as a probe through the Resonance Rayleigh scattering (RRS) technique. The interaction between EryB, Pd²⁺and malathion in the system was investigated by fluorescence, RRS and UV-Vis spectroscopy. Under the optimum conditions, the RRS intensity of EryB, Pd²⁺ and malathion was weak when exist in alone or any two kinds, however, the RRS intensity of the EryB-Pd²⁺-Mala system had an obvious enhancement due to Pd²⁺ could interact with the hydrolysis products of Mala and EryB each other form a new complexes. At the same time, the fluorescence intensity of EryB was decreased significantly in the presence of Pd²⁺, and the fluorescence intensity of EryB-Pd²⁺ system further decreased when Mala added, interestingly. So it was further proved that there was a forming complex in EryB-Pd²⁺-Mala system. Under the optimal conditions, the RRS enhanced intensity of the system was linearly proportional to the Mala's concentration in the range of 0.012-0.8 μg/mL, and the LOD was 1.7 ng/mL, with the correlation coefficient was R² = 0.9960. So, a new method for determination of Mala was established and this method has been demonstrated in real sample with satisfactory results.