Studies On The Determination Method Of 10 Pyrethroids Residues In Aquatic Products

Pyrethroids are a class of broad-spectrum pest to control a variety of pesticides, and they are widely used in aquaculture industry. However, the enrichment of pyrethroids in aquatic products caused the risks of food safety to the people. In recent years, food safety has been the focus of discussion, all state agencies also made the limite on the pyrethroid residues in aquatic products. However, The method of study tefluthrin, fluvalinate, cyfluthrin residues in aquatic products is still less and there is no domestic simultaneous detection method of multiple pyrethroid residues in aquatic products. It is necessary to establish a reliable and accurate methodology to detect variety of pyrethroids in aquatic product, and it satisfies the high sensitivity, low detection limit of quantification.In this experiment, develop the methods to meet the simultaneous determination of 10 pyrethroid by optimizing the conditions for GC detection and preparation procedures of aquatic products sample. This method could simultaneously detecte bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenpropanate, permethrin, deltamethrin, fluvalinate, permethrin, cyfluthrin, 10 pyrethroid. The samples firstly were extracted by organic solvent n-hexane-ethylacetate-acetone (1:2:1, v/v/v), then dislodged fat with acetonitrile saturated by petroleum ether, then purified by Florisil column, and finally determinated by GC-ECD.Through the experiment, the optimal chromatographic conditions: column: HP-5MS (30 m×250μm×0.25μm); detector: ECD; column pressure: 78.9 Kpa; carrier gas: 99.999% pure nitrogen; flow rate: 0.8 mL / min; injector temperature 260℃; detector temperature: 300℃; injection mode: constant voltage mode, splitless injection, injection volume: 1μL.This experimental verification of the method, show that the method in the concentration range of 1~100ng/mL has good linearity, and the correlation coefficient r≥0.99951. In the aquatic blank samples spiked concentration of 2μg/kg, 10μg/kg, 20μg/kg (tefluthrin corresponding to 1μg/kg, 5μg/kg, 10μg/kg) 3 level and the recovery rate was 78.0%~110.0%, and day precision was 4.0%~12.0% (n=6),and inter-day precision was 4.0%~12.0% (n=3); Calculating detection limit with 10 times the signal to noise ratio, the detection limit of tefluthrin was 1.0μg / kg; The detection limit of bifenthrin, fenpropathrin, cyhalothrin, cypermethrin, fenvalerate, deltamethrin, fluvalinate, permethrin, cyfluthrin is 2.0μg/kg. There is some deviation between the measurements and the true value ,leaded by some inevitable experimental error. Assess the uncertainty of this method can provide the theoretical basis for control error. This paper analyzes the source of experiment relative standard uncertainty. Experimental results show that the main source of experiment relative standard uncertainty for gas chromatography measurement of pyrethroid residues in aquatic products is the relative standard uncertainty introducted by standard material recycling and the relative standard uncertainty introducted by the concentration of pyrethroid.Through these studies, the establishment of pyrethroids in aquatic products detected by gas detection methods had accomplished. Experimental results show that the method is simple, easy, high sensitivity and accuracy.