چكيده به لاتين
Abstract
Due to significant effects of fatty acids on the human health, quantitative determination of fatty acids is of prime importance. Fatty acids are found in sources with very complex matrix, and therefore needs especial sample preparation steps prior to analysis. Among different extraction methods, solid phase microextraction (SPME) and solid phase nanoextraction (SPNE) has recently gained notice since they eliminate the need for sample preparation step. In this study, the authors have described a method to extract and quantify alpha-linolenic acid (ALA) in milk by using direct immersion SPNE (DI-SPNE) with the gas chromatography )GC (. The electrospinning process was successfully used to produc polydimethylsiloxane/polyacrylonitrile/titanium dioxide nanofibers (PDMS/PAN/TiO2) as a synthetic composite SPNE coating. The parameters affecting the electrospinning process such as PDMS concentration, amount of TiO2 nanoparticles, voltage, and tip-to-collector distance were optimize using Taguchi’s orthogonal. The SPNE experimental conditions, such as extraction time, agitation rate, pH and salt concentration, were also optimized using central composite design (CCD). The optimum conditions were found to be 46 min, 2000 rpm, 9.5 and 10% w/v for extraction time, agitation rate, pH and salt concentration, respectively. Under the optimized condition, the calibration curve was linear in the range of 1-4000
ng mL-1 with R2=0.998. The repeatability at two concentration levels (10 and 1000 ng mL-1) was calculated. Relative standard deviation was 6-8%, 7.5-8% and 9% for intraday, interday, and fiber-to-fiber, respectively. The limit of detection and limit of quantification were found to be 0.2 and 0.6 ng mL-1, respectively. Omega-3 enriched Damdaran milk was used as a real sample and the relative recoveries were obtained from 92-106%.
Keywords: Solid Phase Nano Extraction, Electrospinning, Composite Nanofiber, Polydimethylsiloxane, Fatty Acid, Design of Experiment, Gas Chromatography
