Resonance Rayleigh scattering method for highly sensitive detection of chitosan using aniline blue as probe

Enhancement of Congo Red-Neomycin Resonance Rayleigh Scattering by Dodecyl Trimethyl Ammonium Bromide and its Application

A simple, rapid, and convenient method for the determination of neomycin based on the ion association method was proposed. In Britton–Robinson buffer solution, neomycin could react with Congo red to form an ionic association, which in turn reacted with dodecyl trimethyl ammonium bromide to form a ternary ionic association. The three were combined in a 1 : 1 : 1 ratio, which significantly enhanced the resonant Rayleigh scattering intensity at 468 nm. The obtained resonant Rayleigh scattering sensor showed a linear relationship with neomycin in the range of 0.07∼1 μg·mL⁻¹. The limit of detection was 0.02 μg·mL⁻¹, and the limit of quantification was 0.037 μg·mL⁻¹. The experimental conditions were optimized. The method was verified based on the ICH rule. The established method could be applied to the analysis of the acceptable recovery rate of neomycin in powdered veterinary drugs.

A resonance Rayleigh scattering method for sensitive detection of chitosan based on supramolecular complex and mechanism study

A convenient and sensitive resonance Rayleigh scattering (RRS) method for the detection of chitosan (CTS) has been developed via forming Cu-Zn supramolecular complex by complexation reaction, hydrophobic force and electrostatic attraction. The microstructure of the complex was characterized by FT-IR, zeta potential, scanning electron microscope (SEM), UV-vis and RRS. Furthermore, the interaction mechanism among Cu(II), Zn(II), CTS and sodium dodecyl benzene sulfonate (SDBS) was studied. The results revealed that CTS and Cu(II) or Zn(II) formed a supramolecular complex with RRS enhancement in weak acid condition. In the presence of SDBS, the RRS intensity of CTS-Cu(II)-SDBS or CTS-Zn(II)-SDBS was significantly higher than that of the binary system without SDBS at the same CTS concentration. The RRS intensity of CTS-Cu(II)-Zn(II)-SDBS was higher than that of CTS-Cu(II)-SDBS and CTS-Zn(II)-SDBS. The RRS intensity increased linearly with the increase of CTS concentration made it possible to determine CTS quantitatively. In the range extending from 0.10 to 5.00 μg/mL, the equation of linear regression was ΔI=1848.8c-138.3 with a correlation coefficient 0.9996, and the detection limit was estimated to be 37.96 ng/mL. The study was successfully applied for the determination of CTS in health food samples, suggesting its great potential toward CTS analysis.

Study on Brilliant Blue-chitosan System by Dual-wavelength Overlapping Resonance Rayleigh Scattering Method and its Analytical Applications

The method was presented for the sensitive and selective determination of chitosan (CTS) in health products with Brilliant Blue (BB) as a probe, based on dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS). In weakly acidic buffer solution, the binding of CTS and BB could result in the RRS intensities getting enhanced significantly at RRS peaks of 344nm and 452nm, and the scattering intensities of the two peaks were proportional to the concentration of CTS within a certain range. When the RRS intensities of the two wavelengths were superposed, the results showed higher sensitivity. Under the optimum experimental conditions, the total of the two increased RRS intensities was linear to the CTS concentration in the range of 0.02-1.80μg/mL and the limit of detection (LOD) was 7.45ng/mL. In this work, the optimum conditions and the effects of some foreign substances were studied. Accordingly, the new method based on DWO-RRS for the determination of CTS was developed. In addition, the effect of the molecular weight and the deacetylation degree between different chitosan molecules was discussed. Finally, this assay was applied to determine the concentration of CTS in health products with satisfactory results.

A simple and selective resonance Rayleigh scattering-energy transfer spectral method for determination of trace neomycin sulfate using Cu2O particle as probe

The stable Cu₂O nanocubic (Cu₂ONC) sol was prepared, based on graphene oxide (GO) catalysis of glucose-Fehling's reagent reaction, and its absorption and resonance Rayleigh scattering (RRS) spectra, transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were examined. Using the as-prepared Cu₂ONC as RRS probe, and coupling with the neomycin sulfate (NEO) complex reaction, a new, simple, sensitive and selective RRS-energy transfer (RRS-ET) method was established for detection of neomycin sulfate, with a linear range of 1.4-112μM and a detection limit of 0.4μM. The method has been applied to the detection of neomycin sulfate in samples with satisfactory results.

The fluorescence and resonance Rayleigh scattering spectra study on the interactions of palladium (II)-Nootropic chelate with Congo red and their analytical applications

A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH=3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd₂·OXI]²⁺, and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd₂·OXI]. CGR₂, which could result in the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λ_ex=λ_em=375nm. This mixture complex not only has higher RRS, but also makes contribution to significant increase of fluorescence, and the same phenomena also were discovered in PIR. The enhanced RRS intensity is in proportion to the PIR and OXI concentration in the range of 0.03-3.0μgmL^-1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3ngmL^-1 and 9.7ngmL^-1. In addition, the DL of fluorescence method for PIR and OXI is 8.4μgmL^-1 and 19.5μgmL^-1. Obviously, the RRS is the highly sensitive method, and the recoveries of the two kinds of nootropic drugs were range from 100.4% to 101.8.0% with RSD (n=5) from 1.1% to 3.1% by RRS method. This paper not only investigated the optimum conditions for detecting nootropics with using RRS method, but also focused on the reasons for enhancing RRS intensity and the reaction mechanism, which in order to firm and contract the resultant. Finally, The RRS method has been applied to detect nootropic drugs in human urine samples with satisfactory results.