A rapid, sensitive and accurate matrix solid phase dispersion-accelerated solvent extraction (MSPD-ASE) method for selective determination of sixteen organochlorine pesticide (OCP) residues in fish samples has been developed and validated. 2 g fresh fish muscle was dispersed with 10 g anhydrous sodium sulfate and 2 g acid alumina thoroughly, and loaded into the stainless-steel extraction cell containing 6 g of acid alumina and 10 g anhydrous sodium sulfate. The temperature 60°C and two extraction cycles of 5 min gave adequate extraction efficiency using DCM-hexane (3:7, v/v) mixture as solvent. Not only the lipids, but also other co-extracts, which peaks mostly located in the forepart of chromatograms and maybe interfere the identification or quantitation of analytes, were eliminated exhaustively, while analytes were extracted selectively. Sixteen OCPs were identified by retention time of standards and quantified using mirex as internal standards. These detected OCPs were confirmed by GC-MS in real samples. The performance of proposed method was evaluated and validated: the detection limits were 0.008-0.05 ng g -1 , relative standard deviations were 1.9-5.0%, and recoveries were 91.0-104.1% spiked at 10 ng g -1 level. The accuracy and precision of proposed method were equal to or better than that of traditional Soxhlet extraction method.
The interaction of Ce(3+) to bovine serum albumin (BSA) has been investigated mainly by fluorescence spectra, UV-vis absorption spectra, and circular dichroism (CD) under simulative physiological conditions. Fluorescence data revealed that the quenching mechanism of BSA by Ce(3+) was a static quenching process, the binding constant is 6.70 × 10(5) , and the number of binding site is 1. The thermodynamic parameters (ΔH = -29.94 kJ mol(-1) , ΔG = -32.38 kJ mol(-1) , and ΔS = 8.05 J mol(-1) K(-1) ) indicate that electrostatic effect between the protein and the Ce(3+) is the main binding force. In addition, UV-vis, CD, and synchronous fluorescence results showed that the addition of Ce(3+) changed the conformation of BSA.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.