استفاده از تكنيك هاي ريز استخراج با حلال همراه با كروماتوگرافي گازي- آشكارساز شعله يونشي براي اندازه گيري حشره كش هاي پيروتيروئيدي در نمونه هاي آبي

چكيده انگليسي :

Use of solvent microextraction techniques followed by gas chromatography flame ionization detector for the determination pyrethroid insecticides in water samples Mahdiyeh Khorasani m khorasani@ ch iut ac ir April 5 2009 Department of Chemistry Isfahan university of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Assist Prof Mohammad Saraji Saraji@cc iut ac irAbstract The pyrethroid pesticides are extensively used in agriculture and as pest control agents in forestry publichealth and household applications because of their selective insecticide activity rapid biotransformation andexcretion by the mammalian catabolic system and their non persistence in the environment despite their highstability to light and temperature They are furthermore very lipophilic compounds The presence of residues ofpyrethroids in environment may possibly contribute to human exposure by ingestion inhalation skin resorption or from the gastrointestinal tract Appreciable levels of pyrethroid residues can occur in food commodities fromcrops food of animal origin e g milk eggs and meat soils sediments and surface ground and drinking water Contamination of fresh water ecosystems occurs either because of the direct discharge of industrial andagricultural effluents or as a result of effluents from sewage treatment works residues can thus accumulate in thesurrounding biosphere Two extraction methods based on single drop microextraction SDME and hollow fiberliquid phase microextraction HF LPME have been compared for the analysis of four pyrethroid insecticide permethrin cypermethrin deltamethrin and fenvalerate in environmental and wastewater samples by gaschromatography flame ionization detection GC FID Single drop microextraction is based on the exposure of amicrodrop of water immiscible extractant phase suspended from the tip of a microsyringe needle to a stirredaqueous sample After extracting for a prescribed period of time the drop is retracted back into the microsyringeneedle and finally injected into the detector to obtain the corresponding analytical signal For SDME the analyteswere extracted from a 3mL sample solution using 3 5 L of hexyl acetate using a 10 L GC syring Experimentalconditions including extraction solvent solvent volume ionic strength extraction temperature and time havebeen investigated optimal conditions were found to be 3 5 L of hexyl acetate stirring speed 600 rpm NaClconcentration 20 w v extraction time 35min Extraction was carried out as follows the hollow fiber wasultrasonically cleaned in acetone After being dried the hollow fiber was cut manually and carefully into 1 3 cmlengths prior to use A 3 0 L aliquot of organic solvent typically xylene was withdrawn into the syringe Theneedle tip was inserted into the hollow fiber and the assembly was immersed in the organic solvent for 10 s inorder for the solvent to impregnate the pores of the fiber wall The prepared fiber was removed from the solventand subsequently immersed in the aqueous sample Finally the organic solvent in the syringe was injectedcarefully and completely into the hollow fiber For HF LPME the analytes were extracted from a 3mL samplesolution using xylene using a 25 L HPLC syring Optimal conditions were xylene as organic solvent stirringspeed 1500 rpm NaCl concentration 30 w v and extraction time 20min The results showed that extractionefficency by HF LPME were 1 27 1 77 fold higher than SDME Analytical parameters such as precision andlimit of detection were also evaluated for HF LPME technique Analysis of the spiked water samples should thatprecision of 8 8 13 1 Limits of detection for the four analytes were between 3 5 from 6 8 g L Key Wordspyrethroid pesticides extraction methods single drop microextraction hollow fiber liquidphase microextraction

خراساني، مهديه

استفاده از تكنيك هاي ريز استخراج با حلال همراه با كروماتوگرافي گازي- آشكارساز شعله يونشي براي اندازه گيري حشره كش هاي پيروتيروئيدي در نمونه هاي آبي

ريزاستخراج با قطره حلال , ريزاستخراج با غشا فيبر توخالي , سرنوشت زيست محيطي