According to the research from the United States Department of Agriculture, the QuEChERS method which extracts pesticides from foods is fast, convenient, cheap, effective, and secure.
When compares to the traditional SPE method, QuEChERS not only uses less solvent but also adopts the novel dSPE which could disperse the SPE purification much quicker. Its method which includes AOAC’s official method and amendment has been posted on the Internet, whose basic steps are as follows:
Step 1: Sample preparation and extraction. Consistently homogenizing the articles, and adding acetonitrile solvent for shaking extraction. More than that, salts, acids, and buffers could be added in order to improve extraction efficiency and protect sensitive analytes. In addition, extraction efficiency could be monitored by adding alternative standards.
Step 2: Extraction Elimination. Clearing up the subsamples of solvent extraction by dSPE, which improves QuEChERS technology. Small polypropylene centrifugal tubes prefilled with MgSO 4 and SPE adsorbent are adopted in order to eliminate the extra water and unnecessary pollution from the extracted samples. After stirring and centrifugation, the purified extraction could be analyzed by multiple techniques.
Step 3: Sample analysis. The sample’s pH could be adjusted in order to protect the sensitive pesticide or exchange the solvent to improve the analysis of GC/MS or LC/MS. The internal standards could be supplemented.