Determination of bovine serum albumin using resonance light scattering technique with sodium dodecylbenzene sulphonate-cetyltrimethylammonium bromide 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.

Urea-based porous organic polymer/graphene oxide hybrid as a new sorbent for highly efficient extraction of bovine serum albumin prior to its spectrophotometric determination

A 3D urea-based porous organic polymer (Urea-POP) was prepared via the reaction of tetrakis(4-aminophenyl)methane and 1,4-Phenylene diisocyanate. The polymer was subsequently reacted with 2D layered nanosheets of graphene oxide (GO) to prepare Urea-POP/GO as a novel and highly efficient sorbent for pre-concentration and extraction of serum albumin samples, prior to spectrophotometric determination. The hybrid material combines advantages of both POP and GO such as hydrophilicity, high dispersion stability, porosity, and having a large number of nitrogen- and oxygen-containing functional groups. Parameters which influence the extraction efficiency such as the amount of the adsorbent, pH of sample solution, ionic strength, adsorption and desorption time were investigated and optimized. For the method, detection limit of 0.068 mg L^-1 and determination coefficient (R²) of 0.9991 were obtained. The intra- and inter-day was calculated with five replicates in the same day and seven consecutive days, respectively. Intra-day and inter-day precisions were 1.7% and 5.9%, respectively. The maximum sorption capacity was 357.1 mg g^-1, which is higher than the other reported sorbents. The proposed method was demonstrated to be sensitive enough for determination of serum albumin from bio-samples.

Binding site identification of metformin to human serum albumin and glycated human serum albumin by spectroscopic and molecular modeling techniques: a comparison study

The interaction between metformin and human serum albumin (HSA), as well as its glycated form (gHSA) was investigated by multiple spectroscopic techniques, zeta potential, and molecular modeling under physiological conditions. The steady state and time-resolved fluorescence data displayed the quenching mechanism of HSA-metformin and gHSA-metformin was static. The binding information, including the binding constants, number of binding sites, effective quenching constant showed that the binding affinity of metformin to HSA was greater than to gHSA which also confirmed by anisotropy measurements. It was determined that metformin had two and one set of binding sites on HSA and gHSA, respectively. Far-UV CD spectra of proteins demonstrated that the α-helical content decreased with increasing metformin concentration. The zeta potential and resonance light scattering (RLS) diagrams provided that lower drug concentration induced metformin aggregation on gHSA surface as compare to HSA. The increase in polarizability was one of the important factors for the enhancement of RLS and the formation of drug/protein complexes. The zeta potential results suggested that both hydrophobic and electrostatic interactions played important roles in the protein-metformin complex formation. Site marker experiments and molecular modeling showed that the metformin bound to subdomain IIIA (Sudlow's site II) on HSA and gHSA.

A resonance light-scattering (RLS) serving for various quantitative events since 1995: a comment proposed towards how to apprehend well the meaning of RLS and its corresponding guiding role

A resonance light-scattering (RLS), which was creatively suggested for the first time by Pasternack et al. in 1993 [R.F. Pasternack, C. Bustamante, P.J. Collings, A. Giannetto, E.J. Gibbs, J. Am. Chem. Soc. 115 (1993) 5393], have been enjoyably practiced by numerous investigators for various quantitative events since 1995, and hitherto many research papers and some review papers have got published on lots of international journals specialized in or related to analytical and/or bioanalytical sciences. As revealed from these published papers of interests, however, it is a pity that the meaning of RLS is often apprehended unsatisfactorily both in theory and in practice. In this comment, as a result, I would like to do my best to propose an apprehension of the meaning of RLS as full and exact as possible and simultaneously I would like to deliver the important guiding role of this proposed apprehension in the course of the applications of RLS for various quantitative purposes.

Study on the interaction among pyronine Y, potassium bromate and naphthols by absorption, three-dimension fluorescence and resonance light scattering spectra and their application

A novel method for the determination of trace naphthols was proposed based on naphthols, potassium bromate and pyronine Y in dilute sulfuric acid medium can react to form ion-association complexes, which not only resulted in the changes of the three-dimension fluorescence spectra, absorption spectra and the quenching of fluorescence, but also resulted in the great enhancement of resonance light scattering (RLS). The characteristics of RLS spectra, the effective factors and optimum conditions of reaction were studied. It was found that the enhanced intensity of RLS at 396 nm was proportional to the concentration of 1-naphthol and 2-naphthol in the range of 41.4 approximately 3024 ng mL(-1) and 38.3 approximately 3068 ng mL(-1), respectively. The urine samples analysis of the relative standard deviation was 3.1-7.1% and the average recovery was 96.0% (n=6). The present method had been applied to the determination of trace naphthols in human urine, the obtained results were in good agreement with those obtained by the HPLC method; moreover, we had carried on an initial study of the reaction mechanism in terms of spectral characteristics.

Resonance light scattering method for the determination of anionic surfactant with acridine orange

The resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency-double scattering (FDS) spectra of sodium dodecylbenzene sulfonate (SDBS) (anionic surfactant (AS)) with acridine orange (AO) system were studied. Experimental results showed that when lambda(em) = lambda(ex) = 537 nm, the RRS peak of AO was greatly enhanced with the increase of SDBS concentration at a pH range of 1.8-4.0. The linear range of the calibration curve for SDBS was 0.028-8.71 mg L(-1) with a detection limit of 8.36 microg L(-1) when the AO concentration was 2.5 x 10(-5)mol L(-1). The method has been applied to the determination of trace amount of AS in environmental water samples with satisfactory results. In addition, when lambda(em) = 321 nm and lambda(ex) = 642 nm, the intensity of FDS was proportional to the SDBS concentration ranging from 0.014 to 8.71 mg L(-1) and the correlation coefficient was 0.993 with a detection limit of 4.31 microg L(-1); when lambda(em) = 642 nm and lambda(ex) = 321 nm, the intensity of SOS was proportional to the SDBS concentration ranging from 0.050 to 8.71 mg L(-1), and the correlation coefficient was 0.993 with a detection limit of 14.9 microg L(-1).