Application Study On The Analysis Method Of Pesticides Residues In Dried Fruits

In this paper,we studied the extraction and purification technology of pesticide residue in four types of dried fruits(raisin,dried dates,walnut,almond).We further optimized the conditions of high performance liquid chromatography–mass spectrometry(HPLC-MS)detection and gas chromatography-mass spectrometry(GC-MS)for detection of the pesticide residue and established a method for the determination of 62 pesticides using solid-phase extraction SPE-HPLC-MS/MS,and the other method for the simultaneous determination of 57 pesticides using SPE-GC-MS.The main research results are as follows:1.A multi-residue analytical method was developed for the determination of 62 pesticides in dried fruits by SPE-HPLC-MS/MS.The results showed that there were good linear relation for 62 pesticides,and the correlation coefficients(r2)were larger than 0.993;The limits of quantitation(LOQs,S/N?10)were ?10 ?g/kg in four types of dried fruits(raisin,dried dates,walnut,almond);when we spiked three levels(1,2 and 4 time(s)of LOQ),the average recoveries for 62 pesticides range of 69.3%-113.5% with the relative standard deviations(RSDs)ranged from 2.6% to 16.2% in raisin;the average recoveries for 62 pesticides range of 68.7%-110.8% with the RSDs ranged from 2.9% to16.9% in dried dates;the average recoveries for 62 pesticides range of 68.4%-108.8% with the RSDs ranged from3.7% to 16.1 in walnut;and the average recoveries for 62 pesticides were in the range of 65.8%-117.3% with the RSDs ranged from 3.7% to 17.6% in almond.2.A multi-residue analytical method was developed for the determination of 57 pesticides in dried fruits by SPE-GC-MS.The results showed good linearity for 57 pesticides,and the correlation coefficients(r2)were larger than 0.991;The LOQs(S/N?10)were ?10 ?g/kg in four different matrix(raisin,dried dates,walnut,almond);when we spiked three levels of 10,50,100 ?g/kg,the average recoveries for 57 pesticides were in the range of 70.1%-109.1% with the RSDs ranged from 5.0% to15.4% in raisin;the average recoveries for 57 pesticides were in the range of 68.8%-109.6% with the RSDs ranged from 3.4% to 16.5% in dried dates;the average recoveries for 57 pesticides were in the range of 74.6%-108.0% with the RSDs ranged from 6.3% to 15.2% in walnut;and the average recoveries for 57 pesticides were in the range of 72.9%-111.6% with the RSDs ranged from 4.9% to 16.2% in almond.3.The above two analytical methods were proven to be highly sensitive and repeatable,and suitable for the monitoring of the maximum residue limits of pesticides in dried fruits.The results made a foundation for the national entry-exit inspection and quarantine industry standards of “Determination of a variety of pesticide residue in dried fruits for exports by liquid chromatography-tandem mass spectrometry”,and it is in favour of dried fruit food export enterprises.