| Rice consumption has increased worldwide over recent decades, as it has become one of the most common food. In China, rice is the most important food supply for nearly 60% of the population. Consequently, food-safety issues of rice are an important matter of concern, Nevertheless, to increase the production during planting, several kinds of pesticides, fungicides, herbicides and insecticides are used to prevent weed growth and to protect crops against pest damage. Consequently, after their application, pesticide residues may remain in rice and constitute a health risk because of their toxicity. In Liaoning ports, rice mainly exports to Japan and South Korea. The study aimed to establish a high-throughput screening confirmatory and quantitative analysis method for determination of the multi-residue pesticides in rice, using the modern sample pretreatment methods and the high resolution mass spectrometry analysis technique. The monitoring of pesticide residues is important not only to provide detecting services for rice export enterprises, but also meet to strict Maximum Residue Limits (MRLs).In this paper, rice samples were studied and the testing items of rice in Japan and South Korea were emphasized. The article studied on parametric condition including mass scanning mode, parent ion, daughter ion, ion source parameters, mobile phase, column temperature, column temperature, etc., then established analysis conditions of 205 pesticides with liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (LC-Q-TRAP/MS) and established EPI fingerprint spectrum of 205 pesticides with multiple reaction monitoring with information-dependent acquisition of enhanced product ion (MRM-IDA-EPI) mode. The study determined two methods by investigating on the extraction solvent, extraction methods, clean way. The first method was quantitatively detection of 193 multi-pesticide residues in rice through ultrasonic extracting by acetonitrile (MeCN), clean-uping by gel permeation chromatography (GPC), analyzing by LC-Q-TRAP/MS. The second method was quickly screen of 205 pesticides in rice samples with pretreatment by Quick Easy Cheap Effective Rugged and Safe (QuEChERS), analyzing by LC-Q-TRAP/MS in MRM-IDA-EPI mode. Both methods can provide a alternative pretreatment way for different laboratories with specific experimental environment, equipment and test items.The study found that the second method covered a wider range of pesticides, a shorter detection cycle for screening and quantitative analysis, less reagent consumption, lower limit of quantification (LOQ). Therefore, the second method was suitable for detection a large number of rice. The second method had been verified in the laboratory and between laboratories, and also were used to analysis of actual rice samples. The results indicated that all the 205 pesticides showed good linear relationship with linear correlation coefficients above 0.995. In this paper,10 times signal to noise ratio (S/N)was used to be as limits of quantification(LOQ), and the LOQs of 205 pesticides were 0.5-10.0 μg/kg, the LOQs of 176 pesticides,3 pesticides,11 pesticides,2 pesticides and 13 pesticides among them are 0.5 μg/kg,5 p,g/kg.2.5 μg/kg,1.25 μg/kg and 10.0 μg/kg, respectively..This method can satisfy the MRLs of China, South Korea, Japan and the European Union and other countries. The results indicated that the average recoveries of the 205 pesticides ranged from 62.4% to 127.1% with the relative standard deviation (RSDs) of 1.9%-20.0% with spiked of 10 μg/kg level,, the average recoveries of the 205 pesticides ranged from 65.9% to 120.3%, with the RSDs were between 1.0% and 18.4% with spiked of 50 μg/kg level. Verified between the laboratories indicated that the average recoveries of 205 pesticides in rice ranged from 69.4%-114.8%, with the RSDs were between 1.3% and 13.3% with spiked of 10 μg/kg level, the average recoveries of 205 pesticides in rice ranged from 73.3%-108.6%, with the RSDs were between 1.3% and 15.7% with spiked of 50 μg/kg level. It is suitable for the simultaneous determination of multiple pesticide residues in rice.This paper analyzed the 205 kinds of pesticides, including insecticide, insecticide metabolites, herbicides, fungicides, and other pesticides, and covered 126 detection items of Japan required and 88 items of Korea’s. It is worth mentioned that 10 detection items were added in 2014. Compared with GB/T 19649-2006,125 items were added in the method and compared with GB/T 20770-2008,76 items were added. The unknown compounds can be confirmed through searching the EPI fingerprint spectrum library of 205 pesticides established in this article, which can improve the accuracy for analyzing non-target pesticides. And this method analyzed pesticides residues in actual rice sample usingonly 20 min. The method is effective, sensitive and can high-throughput screening confirmatory and quantitative determination of pesticide residues in rice. It provides a powerful technical tool for the risk monitoring of rice, which also can provide an effective guarantee for food safety supervision. |
