|NIE, JING - Shanghai Institute For Food And Drug Control|
|MIAO, SHUI - Shanghai Institute For Food And Drug Control|
|LI, WEN-TING - Shanghai Institute For Food And Drug Control|
|ZHOU, HENG - Shanghai Institute For Food And Drug Control|
|MAO, XIU-HONG - Shanghai Institute For Food And Drug Control|
|LU, JI-WEI - Shanghai Institute For Food And Drug Control|
|LAN, LAN - Shanghai Institute For Food And Drug Control|
|JI, SHEN - Shanghai Institute For Food And Drug Control|
Submitted to: Food Additives & Contaminants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2015
Publication Date: 7/9/2015
Publication URL: http://handle.nal.usda.gov/10113/61189
Citation: Nie, J., Miao, S., Lehotay, S.J., Li, W., Zhou, H., Mao, X., Lu, J., Lan, L., Ji, S. 2015. Multiresidue analysis of pesticides in traditional Chinese medicines using gas chromatography - negative chemical ionization tandem mass spectrometry. Food Additives & Contaminants. Part A. 32:1287-1300. doi: 10.1080/19440049.2015.1055340.
Interpretive Summary: Pesticide residue monitoring of food and other agricultural products is commonly conducted for international trade, regulatory, and other purposes to ensure food safety, check product quality, and verify that proper agricultural practices were followed during cultivation of the crop. Some agricultural sample types are very complex, and it is often difficult to detect pesticide residues at very low concentrations in the samples due to matrix interferences. In this study, we monitored 107 diverse pesticides at ultra-trace concentrations in several real-world traditional Chinese medicines, which are extremely complex matrices. A modification of the “quick, easy, effective, rugged, and safe” (QuEChERS) method was used for sample preparation, and analysis was conducted by negative ion chemical ionization in gas chromatography – tandem mass spectrometry (GC-MS/MS). The method was simple, fast, selective, and sensitive, which led to better results than the conventional QuEChERS followed by GC-MS/MS using standard electron ionization. This study demonstrated the real-world applicability of the advantageous new method, which has already been implemented in a major monitoring lab in Shanghai, China, and is likely to be used for complex matrices by many other labs in the future.
Technical Abstract: In this study, a residue analysis method for the simultaneous determination of 107 pesticides in the traditional Chinese medicines (TCMs), Angelica sinensis, Angelica dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin, and Lonicera japonica Thunb, was developed using gas chromatography coupled with tandem mass spectrometry in negative chemical ionization mode (GC-NCI-MS/MS). NCI has advantages of high sensitivity and selectivity to chemicals with electron-withdrawing groups, and yields low background interference. For sample preparation, QuEChERS, which stands for “quick, easy, cheap, effective, rugged, and safe,” was applied. Due to unique characteristics of TCMs, the cleanup step was optimized by adjusting amounts of primary secondary amine, C18, graphitized carbon black, and silica sorbents. Validation was mainly performed by determining analyte recoveries at four different spiking concentrations, 10, 50, 100 and 200 ng/g, with 7 replicates at each concentration. Method trueness, precision, linearity of calibration curves, lowest calibrated levels (LCLs), and matrix effects were determined to demonstrate method and instrument performance. Among the 107 pesticides tested, approximately 80% of them gave recoveries from 80 - 110% and < 10% RSD. The LCLs for nearly all the pesticides were typically 5 ng/g, and even lower (0.1 ng/g) for dichlofenthion, endosulfan sulphate, flumetralin, isofenphos-methyl, methyl-pentachlorophenyl sulfide, and trifluralin. The results indicate that NCI in GC-MS/MS has a favorable future in multiresidue pesticide analysis.