title: Application of QuEChERS method for extraction of selected persistent organic pollutants in fish tissue and analysis by gas chromatography mass spectrometry.
abstract: The QuEChERS method developed for 22 organochlorine pesticides (OCPs) and 7-polychlorinated biphenyls (PCBs) in fish tissue involves a simple and efficient freezing technique for removal of lipids. The equipment developed consists of disposable syringes and a freezing block constructed from simple materials found in most laboratories. The freezing block keeps the temperature in the extract at -20.5°C up to 10 min after being exposed to room temperature. After the freezing step 69% of the lipids in tilapia and 61% in salmon are removed. Further reduction of co-extractives up to 96% in tilapia and 87% in salmon can be made by treatment with CaCl(2) and primary secondary amino sorbent (PSA) which removes the fatty acids. Spiking experiments in tilapia at 5 and 50 ng/g and extracted with acetonitrile show recovery range from 70 to 115% for all compounds. In salmon the recoveries are in the range 43-118% for the OCPs and 26-65% for the PCBs. Analysis of a standard reference material shows acceptable results for most of the pesticides but low results for the PCBs. The estimated LOQs were in the range 1-5 ng/g for tilapia and 2-10 ng/g for salmon. The method has been applied to analyse fish samples from Lake Koka in Ethiopia. It was investigated if addition of a less polar water miscible solvent than acetonitrile could increase the recovery of OCPs and PCBs. The results show that a mixture of 75% acetonitrile and 25% tetrahydrofurane (ACN/THF 75/25) clearly enhances the recoveries for most OCPs (47-101%) and PCBs (42-79%) from salmon. The recovery of aldrin increases significantly from 55% to over 80%. The method using ACN/THF 75/25 is applicable to the extraction of OCPs and PCBs from fish tissue having a lipid content of up to about 11% (salmon) with recoveries ≥70% for most of the OCPs and ≥42% for the PCBs.
authors: Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division, Ås, Norway. hansragnar.norli@bioforsk.no
authors: Hans Ragnar
authors: HR
authors: Norli
authors: Agnethe
authors: A
authors: Christiansen
authors: Ermias
authors: E
authors: Deribe
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000452:Aldrin / Q000032:analysis / Q000302:isolation & purification; D000818:Animals; D003080:Cold Temperature; D004785:Environmental Pollutants / Q000032:analysis* / Q000302:isolation & purification; D005002:Ethiopia; D005618:Fresh Water / Q000032:analysis; D005663:Furans / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000191:economics / Q000379:methods*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis* / Q000302:isolation & purification; D008055:Lipids / Q000737:chemistry / Q000302:isolation & purification; D010573:Pesticide Residues / Q000032:analysis* / Q000302:isolation & purification; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000302:isolation & purification; D012474:Salmon; D012680:Sensitivity and Specificity; D017210:Tilapia
chemical_list: D000097:Acetonitriles; D004785:Environmental Pollutants; D005663:Furans; D006843:Hydrocarbons, Chlorinated; D008055:Lipids; D010573:Pesticide Residues; C018674:tetrahydrofuran; D011078:Polychlorinated Biphenyls; D000452:Aldrin; C032159:acetonitrile