Search

A new resonance light scattering (RLS) method for determining eugenol was developed using gold nanorods (AuNRs) as probes which were synthesized in our lab. The weak RLS intensity of eugenol was obviously enhanced by the use of AuNRs. All of the results from the SEM, RLS and UV spectra indicated that eugenol induced the assembly of AuNRs; thus, a new complex of AuNRs-eugenol was formed. The assembly of this new complex was achieved through a coordination bond between eugenol and AuNRs. Under optimum experimental conditions, a direct linear relationship was established between the enhancement of RLS intensity and the concentration of eugenol in the range of 0.043-10.60 μg ml(-1) (r=0.9927). Moreover, the limit of detection (LOD) was found at a nanogram level (7.28 ng ml(-1) by 3S0/S). The recovery and RSD (n=5) of three synthetic samples were 99.7-104.2% and 0.81-1.19%, respectively. The method was successfully employed for the analysis of eugenol in curry powder samples., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A new method for the determination of calf thymus DNA at nanogram level was proposed based on the enhanced resonance light scattering (RLS) signals of DNA in the presence of procyanidin and cetylpyridinium bromide dihydrate (CPB). Under the experimental conditions, the RLS intensity of DNA at 291.0 nm was greatly enhanced by procyanidin-CPB at pH 7.0. There was a good linear relationship (r=0.9993) between the enhanced RLS intensity (ΔI(RLS)) and DNA concentration of 0.0084-3.36 μg mL(-1). The limit of detection (LOD) was 2.27 ng mL(-1) (3S0/S). Three synthetic DNA samples were measured with satisfactory, and the recovery was 102.3-107.2%., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The paper explores the method of determination of salmeterol xinafoate at nanogram level with gold nanoparticles (AuNPs) probe, to measure the intensity of resonance Rayleigh light scattering (RLS) by a common spectrofluorometer. The RLS intensity of salmeterol xinafoate was greatly enhanced by AuNPs, with the maximum scattering peak at 357 nm. The salmeterol xinafoate was determined basing on the binding of salmeterol xinafoate to AuNPs by electrostatic adsorption. Under the optimum conditions, the enhanced RLS intensity was directly proportional to the concentration of salmeterol xinafoate in the range of 0.054-6.038 μg mL(-1) with a good linear relationship (r=0.9928). The limit of detection (LOD) was 9.48 ng mL(-1). The interference tests were performed carefully. With the proposed method, the synthetic samples were analyzed satisfactorily, the recovery and RSD were 102.5-103.0% and 0.67-1.0% respectively., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The interaction of terbutaline sulfate (TS) with calf thymus DNA (ctDNA) were investigated by fluorescence quenching, UV-vis absorption, viscosity measurements, ionic strength effect, DNA melting experiments and molecular docking. The binding constants (Ka) of TS to ctDNA were determined as 4.92×10(4), 1.26×10(4) and 1.16×10(4) L mol(-1) at 17, 27 and 37 °C, respectively. Stern-Volmer plots suggested that the quenching of fluorescence of TS by ctDNA was a static quenching. The absorption spectra of TS with ctDNA revealed a slight blue shift and hyperchromic effect. The relative viscosity ctDNA was hardly changed by TS, and melting temperature varied slightly. For the system of TS-ctDNA, the intensity of fluorescence decreased with the increase of ionic strength. Also, the Ka for TS-double stranded DNA (dsDNA) was clearly weaker than that for TS-single stranded DNA (ssDNA). All these results revealed that the binding mode of TS with ctDNA should be groove binding. The enthalpy change and entropy change suggested that van der Waals force or hydrogen bonds was a main binding force between TS and ctDNA. Furthermore, the quantum yield of TS was measured by comparing with the standard solution. Based on the Förster energy transference theory (FRET), the binding distance between the acceptor and donor was calculated. Molecular docking showed that TS was a minor groove binder of ctDNA and preferentially bound to A-T rich regions., (Copyright © 2015 Elsevier B.V. All rights reserved.)