Improvement of QuEChERS Pre-Processing Method
Selection of scavengers
The conventional QuEChERS method only uses PSA which is too simple single that can no longer meet the complex matrix samples examination experiments. GCB (graphitized carbon black) can effectively adsorb pigments, and non-polar interferences such as sterol due to its special chemical structure., GCB can achieve 90% adsorption of pigments, and have a good purification effect on samples with higher pigment content such as amaranth and spinach. C18 mainly absorbs non-polar interferences such as fat through silica gel matrix adsorbent and has an excellent effect on animal-source agricultural products with high-fat content. In addition, there are various kinds of cleaning agents, zirconium dioxide, aluminum oxide, EMR-Lipid, etc. Choose a suitable combination of purifying agents according to different samples, which is beneficial to improve purification efficiency.
Water addition to the sample
The QuEChERS method mainly applies pesticide extraction to vegetables and fruits with high water content; for samples with low water content such as chicken, milk powder, rice, and other agricultural products, it is necessary to appropriately add the appropriate amount of water (the sample moisture content should be higher than 80%) to ensure extraction efficiency. Different water additions have a certain influence on the test results.