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Development of Liquid-Phase Microextraction Technique Combined with Gas Chromatography and Chemometric Techniques for Extraction and Determination of Some Pesticides in Saffron
, M.Sc. Thesis Sharif University of Technology ; Parastar Shahri, Hadi (Supervisor)
Abstract
Today, with increasing concerns about the health of food and its effects on human health, ensuring the quality of food has become a big challenge for regulatory institutions. This issue is more important in the case of foods that have high nutritional and economic value. Among different food items, saffron is especially important due to its low production rate and high economic value. In this research, a new approach based on the diffusion liquid-liquid microextraction method (DLLME) along with gas chromatography-flame ionization detector (GC-FID) combined with chemometrics techniques has been developed to measure the amount of two pesticides in saffron. In this regard, in the extraction...
Biopolymeric based Interpenetrating Polymer Network for Extending the Microextraction Techniques
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib (Supervisor)
Abstract
In this study, gelatin/polyvinylpyrrolidone semi interpenetrating polymer network scaffold was synthesized in presence of glutaraldehyde as a cross linker and a porous structure was obtained by freeze drying method. The biocompatible network with properties like huge porosity, good thermal stability and establishing different interactions, was employed as an extractive phase in needle trap device and used for evaluation of benzene, toluene, ethylbenzene and xylene (BTEX) in conjugation with gas chromatography-flame ionization detector. For investigating semi interpenetrating polymer network efficiency, Different ratios of gelatin and polyvinylpyrrolidone (gelatin/polyvinylpyrrolidone: 1:0,...
A single–step synthesized supehydrophobic melamine formaldehyde foam for trace determination of volatile organic pollutants
, Article Journal of Chromatography A ; Volume 1525 , 2017 , Pages 10-16 ; 00219673 (ISSN) ; Zeinali, S ; Baktash, M. Y ; Sharif University of Technology
Abstract
Superhydrophobic materials have attracted many attentions in recent years while their application in sample preparation remained almost intact. In this project, a rough surface of melamine formaldehyde foam was silanized by chemical deposition of trichloromethylsilane to form a highly porous and superhydrophobic material, presumably a suitable medium for extracting non–polar compounds such as benzene and its methyl derivatives. The prepared sorbent was packed in a needle for the headspace needle–trap microextraction of benzene, toluene, ethylbenzene and xylenes (BTEX). Major parameters associated with the extraction/desorption processes were considered for optimization. Under the optimized...
Development of multi-response optimization and quadratic calibration curve for determination of ten pesticides in complex sample matrices using QuEChERS dispersive liquid–liquid microextraction followed by gas chromatography
, Article Journal of Separation Science ; Volume 42, Issue 23 , 2019 , Pages 3553-3562 ; 16159306 (ISSN) ; Parastar, H ; Sharif University of Technology
Wiley-VCH Verlag
2019
Abstract
In this study, QuEChERS combined with dispersive liquid-liquid microextraction is developed for extraction of ten pesticides in complex sample matrices of water and milk. In this regard, effective factors of proposed extraction technique combined with gas chromatography with flame ionization detector were designed, modeled, and optimized using central composite design, multiple linear regression, and Nelder–Mead simplex optimization. Later, univariate calibration model for ten pesticides was developed in concentration range of 0.5–100 ng/mL. Surprisingly, quadratic calibration behavior was observed for some of the pesticides. In this regard, Mandel's test was used for evaluating linearity...