Some Case Of QuEChERS
The QuEChERS method has the following advantages :(1) high recovery rate, which is greater than 85% for a large number of polar and volatile pesticide varieties;(2) high accuracy and accuracy, can be corrected by internal standard method;(3) a wide range of analyzable pesticides, including polar and non-polar pesticide species, can be used to obtain a good recovery;(4) fast analysis speed, able to complete the processing of 6 samples within 30min;(5) less solvent, less pollution, low price, and no chlorine-containing solvent;(6) it is easy to operate and can be completed well without good training and higher skills;(7) acetonitrile is immediately sealed after being added to the container, so as to reduce its contact with the staff;(8) very few glassware is used in the sample preparation process, and the device is simple.
How to have your cake and eat it?
Sample preparation in food safety is an eternal topic. Let’s get a sense of where it’s going.
Case 1 [gc-ecd analysis, residues of 4 pyrethroid insecticides in green pepper]
Is mass spectrometry the only way to detect this? No!No!No!Can you use gas chromatography? That how many existing standards can be used ah. For laboratories without GC-ms /MS, this is the most economical option.
Sample: green pepper
Test target: 4 kinds of pyrethroid insecticide
Purification and detection: mpfc-quechers complex matrix purification column;GC – ECD
– average recovery: 88%~110%
-rsd: 0.4%~8.0% (n=3)
Conclusion: using mpfc-quechers complex matrix purification column, the method can even be transferred to gas chromatography, single quadrupole GC-ms.Users who have not yet added GC-ms /MS can immediately experience the simplicity of the QuChERS method.
Case 2 [pesticide residues in grains: removing pigments, fats, sugars, and vitamins at the same time]
The grain is a high-starch matrix, rich in pigments, lipids, sugars, vitamins and other substances, pesticide residue determination of the matrix is also very complex.
Samples: rice, wheat, and corn
Detection Target: more than 100 pesticide residues
Purification and detection: mpfc-quechers high-fat purification column;GC – MS/MS
– in the process of method verification, all pesticides obtained satisfactory linearity, with the regression coefficient (R2) greater than 0.9958
– the average recovery rate of 121 pesticides ranges from 70% to 120%, with RSD less than 20%
-lod and LOQ were 0.1~1.3 and 0.2~4.3 g/kg, respectively
Conclusion: compared with d-spe and SPE methods, high-fat purification with mpfc-quechers can be accomplished in a few seconds without the need for leaching and elution steps. This method has been successfully applied to pesticide detection in market samples.
Case 3 [pretreatment of veterinary drug residue determination]
Most of the QuEChERS with dispersed matrix could not be used as veterinary drug residue pretreatment, which greatly reduced the application popularity of QuEChERS. Can the above pretreatment methods be used for the determination of veterinary drug residues?
Sample: carp, giant salamander, bass
Detection Target: residual of malachite green, diethylstilbestrol and its metabolites
Purification and detection: sin-quechers Nano purification column; LC-MS/MS
– add concentration 0.5, 5, 50 g/kg (n=5)
– recovery: 73-106%
– RSD: < 15%
– CC alpha: 0.10 to 0.51 mu g/kg
– CC beta: 0.10 to 0.52 mu g/kg
Conclusion: the residue of malachite green, diethylstilbestrol and its metabolites can be determined. Sulfonamides, chloramphenicol, temicorin, tam-agonists, and other antibiotics; As well as chloramphenicol in eggs, the purification column can be used to obtain a good recovery rate and good stability.
Cast: the QuEChERS series
The technology principle
QuEChERS series adopted a new type of nanocomposites, multi-wall carbon nanotubes (MWCNTs), as solid-phase adsorption materials, with larger specific surface area, more stable chemical properties, lower biological toxins, less environmental pollution, and better purification effect.
QuEChERS series products have unique industrial design, automatic precision production technology, to ensure the stability of products between batches.
The QuEChERS series has five advantages
1. Good purification effect
New nanocomposite fillers, especially for plant pigments, lipids, some sugars, sterols, phenols, waxes, alkaline disruptors, organic acids and other acidic substances, can obtain excellent purification effect.
2. Easy operation and low experimental requirements
Unique industrial design and filling technology, easy to operate, reduce the experimenter to weigh the loading column operation, PSA and other dispersed matrix does not have the operation error into the liner problem.
3. Fast and efficient, no special SPE equipment is required
The pretreatment requires no special SPE equipment, only one centrifuge, and the purification can be completed in one step, and the whole process can be completed in only 10 minutes, saving 1/2 of the time compared with ordinary QuEChERS.
4. Wide application
QuEChERS series can not only be applied to pesticide residues and animal residues, but also have been extended to the detection of mycotoxins and antibiotics.Even future clinical tests may play a role.
5. The method is mature, the product is stable, and the experimental results are stable and repeatable
After a large number of experiments, the QuEChERS series met all the standards, and the methods were in compliance.And different batches of products are stable, so as to ensure the stability and repeatability of experimental results.
QuEChERS series products can be treated with the following kinds of samples to obtain satisfactory extraction efficiency (recovery) :
· determination of agricultural residues of simple matrix fruits and vegetables,
· polyresidues in plant-based foods such as leafy greens, root potatoes, tea, tobacco and tobacco products
· determination of quinolone residue and clenbuterol residue in animal-derived food and feed samples
· determination of multiple pesticide residues in tea
Did QuEChERS bring more benefits to the trial users?
1. Good purification effect and compliance with laws and regulations.
2. Easy operation, time saving and efficiency improvement of testing laboratory.
3. Innovate technology to provide more references for method evaluators.
4. Help scientific research users build new methods, expand more applications and publish articles quickly.