HS-SPME-GC-ECD Method Is Used To Detect Pyrethroid Pesticide Residues In Beef

Pyrethroid pesticides are modified from pyrethrin,a natural insecticide in chrysanthemum plants.Compared with previous organochlorine,organophosphorus and carbamate pesticides,they have better safety,high efficiency,stable illumination and low environmental harm,and are widely used in agricultural production.This study will head space-solid phase microextraction(HS-SPME)technology applied to beef for common strain pesticides(bifenthrin ester,deltamethrin fluorine,trifluoro cypermethrin,fluorine cypermethrin benzyl,cypermethrin,permethrin and fenvalerate)direct determination of residue,methods the homogenate machine directly after homogenate,ultrasonic assisted extraction,headspace solid phase microextraction-by gas chromatography with electron capture detector(HS-SPME-GC-ECD)analysis method.Analysis conditions and results are as follows:Optimization conditions of pretreatment: PDMS extraction head,25% sodium chloride solution and stirring magneton were added,stirring speed was set at 600 RPM at 90?,headspace extraction was performed for 40 min,and then analyzed for 3min at the injection port temperature of 270?.Gas chromatographic conditions: DB-608 quartz capillary column(30m×0.25mm× 0.25ms);The carrier gas is high purity nitrogen with a purity of > 99.999%.Column velocity: 1.4ml /min;Tail blowing was high-purity nitrogen,flow rate: 46 mL/min;Inlet temperature: 270?;Non-shunt sample injection for 3.0min;Detector temperature: 320?;Column heating procedure: the initial temperature was 150?,stayed for 1min,rose to 270? at 8?/min,and remained at 32 min.The results showed that pyrethroid pesticides could be extracted from beef substrate with little interference,and the whole pretreatment process was simple and quick.Under the above conditions,the theoretical number of pyrethroids was more than 50000.the seven pyrethroids were linear within 10-100 mu.g/L,and the correlation coefficients were all greater than 0.99.The detection limit was 3 to 7 micron /kg,and the quantitative limit was 10 to 20 micron/kg.The recoveries of 7 pyrethroids were as follows: 90%~120%,precision RSD < 15%.This experiment tested beef samples purchased at different periods in the local market.It was found that only the samples purchased in August had just reached the detection limit,but were lower than the European Union limit,and all were qualified goods.Compared with the traditional method of sample pretreatment,SPME does not use organic solvent,has simple and quick operation,low cost,and USES little beef.The method meets the standard requirements of pyrethroid pesticide residues in beef.