كاربرد ريزاستخراج مايع- مايع- مايع براي اندازه گيري اسيدهاي فنولي در نمونه هاي آب ميوه توسط كروماتوگرافي مايع با عملكرد بالا و كاربرد ريزاستخراج با قطره حلال در فضاي فوقاني براي اندازه گيري 28 تركيب آلي فرار در نمونه هاي آبي توسط كروماتوگرافي گازي

چكيده انگليسي :

Application of Liquid Liquid Liquid Microextraction for Determination of Phenolic Acids in Juice Samples by High Performance Liquid Chromatography And Application of Microextraction with Solvent Drop in Headspace for Determination of 28 Volatile Organic Compounds in Water Samples by Gas Chromatography Fatemeh Mousavi fa mousavi20022002@yahoo com March 1 2009 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Mohammad Saraji Email address Dr Saraji@ cc iut ac irAbstractIn this research project at first a preconcentration and clean up technique which involves liquid liquid liquid microextraction was developed to determine antioxidants in natural and commercial juices A layer oforganic phase was impregnated into the pores of a 3 5 cm long porous hollow fiber while the internal volumeof the fiber was filled with NaOH solution as an acceptor solution that was connected directly to the needleof a microsyringe The fiber was then immersed into 5 ml of acidified aqueous samples When the samplesolution was stirred acidic analytes were extracted into the organic phase and back extracted simultaneouslyinto the alkaline acceptor medium as the analytes were protonated at low pH and deprotonated at highbasicity After extracting for a prescribed time 7 l of the acceptor solution was taken back into the syringe After addition of 13 l of internal standard solution to extracts the mixture was injected in to the HPLC DAD system via sampling loop for quantification Effective parameters on LLLPME such as solvent type pH of donor sample basicity of acceptor phase sample stirring rate amount of salt extraction temperatureand time extraction were studied The best extraction efficiencies was achieved by hexylacetate as a solvent pH 2 0 for sample solution basicity of acceptor phase was 0 020 molar NaOH 1500 rpm for stirring rate and extraction time of 30 min in room temperature in a solution with concentration of 0 3 g ml NaCl insample The analytes were extracted quantitatively from the sample solution into the acceptor solution with alarge enrichment factor Due to its low cost the hollow fiber extraction device was disposed of after a singleextraction that eliminated the possibility of carry over effects For this method reproducibility range wasfrom 4 4 to 11 2 and the limits of detection range was between 0 01 and 2 00 g L were obtained Inaddition because a small volume of organic solvent was required and little waste is generated the procedureis environmentally friendly and is compatible with the green chemistry concept At last the proposedmethod was surveyed for analysis of real samples such as natural juice apple juice grape juice and orangejuice and commercial juices pomegranate and sour cherry juice of shadli firm and rani orange juice In the second study determination of volatile organic compounds was studied Various purgeable Aromaticsand Alkenens are the main constituents of petroleum and contamination of water by petroleum constituentsis one of the most important environmental problems HS SDME method used for the extraction of 28volatile organic compounds from water samples and analyzed with gas chromatography flame ionizationdetector Parameters such as organic solvent organic drop volume stirring rate salt concentration extraction temperature and exposure time were optimized Overall the extraction was done by suspending a3 0 L isoamylbenzoat drop at the tip of a 10 0 L microsyringe at the headspace of 2 ml donor aqueoussolution with concentration of 0 1 g ml NaCl and stirred at 1300 rpm at room temperature for 30 minutes The relative standard deviation was in the range of 4 3 11 8 and the limit of detection was in the range of0 02 0 04 mg L Key WordsLiquid Liquid Liquid Microextraction Hollow fiber based Microextraction PhenolicAcids Head Space Single Drop Microextraction Volatile Organic Compounds

موسوي، فاطمه

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