High Accuracy Method For PFOA And PFOS In Oysters And Development Of The Certified Reference Material

Perfluorooctanoic acid(PFOA)and Perfluorooctane sulfonate(PFOS)are typical perfluorinated compounds in the environment.They are ubiquitous in the environment and result in a variety of thazards to the human.They have attracted attention worldwide and become a new class of persistent organic pollutants.PFOA and PFOS have been detected in water,soil,sediments,organisms,etc.The detection rates of PFOA and PFOS in the aquatic organisms were the highest.The main exposure route of PFOS and PFOS in the population is dietary intake,especially the intake of aquatic products such as fish and shellfish.And shellfish is often used in monitoring programs for organic pollutants.Therefore,the detection and analysis of PFOA and PFOS in aquatic products has become a current research focus.The development of relevant reference materials can ensure the accuracy,comparability,and traceability of the test results,and meet the needs of actual detection.First,this paper established a high-accuracy method for the determination of perfluorooctanoic acid and perfluorooctane sulfonic acid in oysters—isotopic dilution liquid chromatography tandem mass spectrometry.The extraction efficiency of different extraction agents such as acidified acetonitrile and methyl tert-butyl ether for PFOS and PFOS in oysters were compared.The purification efficiency of WAX solid phase extraction,HLB solid phase extraction and QuEChERS method were investigated.The washing and elution procedures of WAX solid phase extraction were optimized.The different sample solutions and filter were also compared.And the liquid chromatography conditions and mass spectrometry parameters of PFOA and PFOS were optimized.Finally,the paper established to extract oysters with methyl tert-butyl ether,and to clean the samples with WAX solid phase extraction.Using 13C4-PFOA and 1,2,3,4-13C4-PFOS as internal standards,PFOS and PFOS in oysters were determined by high performance liquid chromatography tandem mass spectrometry.The method quantitation limits of PFOA and PFOS are 0.10 ?g/kg and 0.015 ?g/kg,respectively.The method has good linearity in the range of 0.03 ?g/kg-12.50 ?g/kg and 0.005 ?g/kg-10.00 ?g/kg.It has good repeatability and meets the development requirements of oyster reference materials.Second,oyster matrix reference material candidate was prepared by adding PFOA and PFOS to blank samples.The preparation process of oyster matrix reference material candidate was explored.Before packaging,the homogeneity of t reference material candidate was preliminarily tested.Then the effects of the packaging bottles of different materials on the PFOA and PFOS in the oysters were investigated.The total number of colonies of oyster before and after irradiation was determined.The results showed that oyster matrix reference material candidate passed the homogeneity test,the polyethylene packaging bottle was selected.The concentrations of PFOA and PFOS before and after irradiation did not change significantly,and the samples could be stored for a long time after irradiation.Finally,isotopic dilution mass spectrometry was used to determine of PFOA and PFOS matrix reference materials in oysters,and the uncertainty was systematically evaluatedxianzaialues of PFOA and PFOS were 5.63 ?g/kg±0.35 ?g/kg and 3.08 ?g/kg±0.20 ?g/kg,respectively.The homogeneity and stability of the reference material were investigated.The results show that the oyster matrix reference material has good homogeneity.The value of PFOA and PFOS in oyster matrix reference material remains stable when it is transported at 50? for 9 days.It can be stored for 6 months at-20?.This matrix reference material will make up for the blanks of PFOA and PFOS in matrix reference material in China,meet the needs of actual sample testing,and ensure the accuracy,comparability,and traceability of test results.