Resonance light scattering technique for the determination of proteins with polymethacrylic acid (PMAA)

High-performance liquid chromatography associated with resonance Rayleigh scattering spectral study of the interactions of palladium(ii)–antimigraine chelates with Erythrosin B and their analytical applications

For the first time, a highly sensitive and selective detection technology of high-performance liquid chromatography associated with resonance Rayleigh scattering spectra (HPLC-RRS) is applied to analyze migraine drugs including zolmitriptan (ZON) and rizatriptan (RIN).

A sensitive resonance Rayleigh light scattering method for alpinetin using gold nanorods probes

A sensitive resonance Rayleigh light scattering (RLS) assay for alpinetin was developed based on alpinetin-modified gold nanorods (AuNRs). Alpinetin could interact with AuNRs and formed a new assembly by electrostatic attraction. In pH 7.4 Tris-HCl buffer solution, the assembly of alpinetin-AuNRs showed a sensitive RLS signal. Under optimum conditions, the magnitude of enhanced RLS intensity (ΔI_RLS ) was proportional to the concentration of alpinetin over the range 0.027-3.24 μg ml^-1 , with a detection limit of 1.79 ng ml^-1 (by 3σ). The developed RLS method was successfully applied to the detection of alpinetin in real or synthesized samples. Alpinetin recoveries were 90.4-108.7% with an RSD of 0.82-2.9% (n = 5) for Alpinia katsumadai samples, and 95.1-103.7% with an RSD of 0.28-3.9% (n = 5) for synthesized samples. The results showed that this new approach was convenient, reliable and sensitive.

Preparation and Characterization of Hydrophobic-Associated Microspheres for Deep Profile Control in Offshore Oilfields

Microspheres have excellent sealing performances such as injectivity, bridging-off, deep migration, and deformation performances, but their plugging effects are limited by the fast swelling rate and poor viscoelasticity. In this study, we synthesized a novel modified microsphere with polymerizable surfactant monomers and cationic monomers. We investigated the influence factors on the swelling performance and rheological properties of the microspheres and explored the ways to improve the plugging performance of hydrophobic-associating microspheres. The association behaviors in aqueous media of poly(acrylamide-co-methacry loyloxyethyl trimethyl ammonium chloride-co-n-dodecyl poly(etheroxy acrylate) P(AM-DMC-DEA) are proven to be mediated by the DEA content. Moreover, the hydrophobic association interaction has a strong effect on the performance of microspheres such as swelling properties, the rheological performance, and plugging properties. The swelling properties of microsphere studies exhibited the slow swelling rate. The rheological performance measurements showed significant improvements; yield stress, and creep compliance increased rapidly from 404 to 2060 Pa and 3.89 × 10−4 to 1.41 × 10−2 1/Pa, respectively, with DEA content in microspheres rising from 0.0% to 0.22%. The plugging properties of microspheres were enhanced by the slow swelling performance and good viscoelasticity.

Interaction between holo transferrin and HSA-PPIX complex in the presence of lomefloxacin: an evaluation of PPIX aggregation in protein-protein interactions

Human serum albumin (HSA) and holo transferrin (TF) are two serum carrier proteins that are able to interact with each other, thereby altering their binding behavior toward their ligands. During the course of this study, the interaction between HSA-PPIX and TF, in the presence and absence of lomefloxacin (LMF), was for the first time investigated using different spectroscopic and molecular modeling techniques. Fluorescence spectroscopy experiments were performed in order to study conformational changes of proteins. The RLS technique was utilized to investigate the effect of LMF on J-aggregation of PPIX, which is the first report of its kind. Our findings present clear-cut evidence for the alteration of interactions between HSA and TF in the presence of PPIX and changes in drug-binding to HSA and HSA-PPIX complex upon interaction with TF. Moreover, molecular modeling studies suggested that the binding site for LMF became switched in the presence of PPIX, and that LMF bound to the site IIA of HSA. The obtained results should give new insight into research in this field and may cast some light on the dynamics of drugs in biological systems.

Resonance light scattering method for the determination of DNA with cationic methacrylate based polymer nanoparticle probes

Narrowly distributed cationic poly (methyl methacrylate-co-diacetone acrylamide) (P(MMA-DAAM)) nanoparticles were successfully prepared by microemulsion polymerization. Photon correlation spectrometer (PCS) measurement and transmission electron microscope (TEM) observation revealed that z-average particle size of P(MMA-DAAM) is ∼27.5 nm. It was found that these cationic nanoparticles interact with DNA through electrostatic interaction to form P(MMA-DAAM)-DNA complex, which significantly enhances the resonance light scattering (RLS) signal. Therefore, a novel method using this polymer nanoparticle as a new probe for the detection of DNA by RLS technique is developed in this paper. The results showed this method is very convenient, sensitive, and reproducible.

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.

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).