Academic literature on the topic 'Solid phase extraction method'

The purpose of this study was to develop and optimize a simple and economical method for the extraction and determination of bisphenol-A (BPA), using high-performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection at environmentally relevant concentrations in both dissolved and particulate phases. To clean-up and pre-concentrate liquid samples, solid-phase extraction (SPE) method was optimized with regard to pH, volume, washing and elution solvents for high recovery of BPA and good clean-up. For sludge samples, four extraction methods, microwave-assisted extraction (MAE), ultrasonication extraction (USE), accelerated solvent extraction (ASE) and high-pressure homogenizer (HPH), were compared for isolation of BPA from activated sludge samples. Analysis was performed by optimized procedures using HPLC–UV. Recoveries of BPA from liquid and solid phases were determined to be 90–105 and 60–90%, respectively. MAE had the highest recovery among examined extraction methods. The method detection limits were 100 ng/L and 100 ng/g dry weight. To validate the method, a mass balance study was conducted with 100 mL spiked mixed liquor volatile suspended solids (VSS) samples from three laboratory-scale porous pot reactors and concentrations of BPA in liquid and solid phases were determined using the optimized conditions. The results had an average 86% overall recovery for all samples.

Solid-phase microextraction coupled with gas chromatography was used for the analysis of volatile aroma compounds in Niva cheese. The extraction conditions were very mild, which minimises thermal, mechanical, or chemical modification of the sample; the method is rapid, simple, and cheap. In total, 54 compounds were identified in Niva cheese using this method: 3 hydrocarbons, 5 aldehydes, 11 ketones, 18 alcohols, 3 esters, 10 fatty acids, and 4 sulphur compounds. These aroma compounds were quantified and subsequently the changes in the concentrations of them were studied throughout the ripening period. Most of the volatile compounds identified were present at all stages of the cheese ripening, their amounts changing significantly, however, in most cases the final concentration in the ripe cheeses was similar to the initial concentration in the unripe cheese.  

Based on the principle of solid phase extraction (SPE) and the special immunoreaction, a microfluidic chip integrated with porous matrix was developed for protein extraction. Porous matrix was achieved by electrochemical etching silicon in a HF/ethanol mixture, which was coated on the wall of the rectangular channel of the microchip to provide a surface-enlarging matrix. The surface morphology of the bare porous silicon and the porous silicon modified with the protein has been characterized by SEM. Non-porous chip and porous chip were used to extract protein. Compared with non-porous matrix, the porous matrix achieved higher extracted efficiency of protein. Then two methods of surface modification were employed on porous matrix for protein extraction. The surface modification with Protein A could extract more protein with less non-special absorption. Evaluation of the structure of the solid phase matrix and the surface modification process in the microfluidic chip, the porous microfluidic chip is able to be suitable for incorporation into micro total analysis system (μTAS).