Two Stages Of QuEChERS Pre-Treatment
If a batch of samples is calculated in 6-12, 1 analyst + QuEChERS pre-treatment + 40 min = complete, QuEChERS pre-treatment requires only two simple steps – first extraction and purification, simple optimization in the pre-treatment process can also be improved The efficiency of extracting the target.
1.Extraction stage: the extraction salt component is magnesium sulfate and sodium chloride and other buffer salts. The salting-out effect can separate the water layer from the acetonitrile liquid. During the extraction process, the extraction efficiency of different pesticides can be increased by adjusting the pH. For example, some alkali-sensitive pesticides are relatively stable under acidic systems, and reagents such as AOAC and EN with buffer salts can be used.
2.Purification stage: After high-speed centrifugation, the sample will be stratified. The uppermost layer is the acetonitrile layer in which the target substance is dissolved. A certain amount of the acetonitrile layer solution is taken into the centrifuge tube to which the dispersion-type purification adsorbent is added in advance.
Taking food as an example, The purification tube used contains a certain proportion of PSA, MgSO4, etc. If the fat content of the sample is high, C18 can be increased; if the pigment content of the sample is high, GCB can be added, the purpose of optimization is good parallelism and high Add recovery rate.