QuEChERS Method for Detection of Sulfonamides in Pork
QuEChERS, standing for “quick, easy, cheap, effective, rugged and safe,” is a newly developed sample pretreatment technology for agricultural product detection in recent years. To have a quick and better understanding of QuEChERS, there are two main parts below that should be well-known.
Procedures of QuEChERS
QuEChERS pre-treatment only requires two steps – extraction and purification. For the extraction stage, the extraction salt component consists of magnesium sulfate, sodium chloride, and other buffer salts.
Due to the salting-out effect, the water layer can be separated from the acetonitrile liquid. In this process, the extraction efficiency of different pesticides can be increased by adjusting the pH. In the purification stage, the sample will be stratified after high-speed centrifugation, which means that the uppermost layer is the acetonitrile layer where the target gets dissolved.
And then, take a certain amount of acetonitrile layer solution into the centrifuge tube where the dispersed purification adsorbent is added, such as PSA.
Advantages of QuEChERS
Compared with other similar analytical technologies, one of the most noticeable advantages of the QuEChERS analytical approach is its high recovery rate for a wide range of pesticides with diverse chemical performances. The recovery rate for the samples is generally kept above 85%.
Besides, it is also featured for its rapid analytical speed. For instance, one single operator can finish the analysis for 6 samples just in half an hour. Also, it could be simply used with low cost, less contamination, and no chloride solvent.
After a long-term intake of animal foods that contain sulfonamide residues, there would be lots of it that accumulate in our body. Beyond a certain quantity, it will damage the urinary system and cause the side effect of resistance to the drug. QuEChERS Method, fortunately, could do a great favor in the detection of sulfonamides, especially in pork.
The traditional detection of sulfonamides is carried out by a solid-phase extraction (SPE) method. Although it can effectively remove impurities and extract sulfonamides from pork, it is accompanied by complicated operating procedures, such as activation, leaching, elution, nitrogen blowing, etc.
Nevertheless, compared with the SPE method, there are only two main steps for QuEChERS method – sample extraction and purification, which greatly reduces labor and time. The recovery rate could reach 80%-90%.
During the sample extraction phase, accurately weigh 2.0g of crushed pork and put it in a 50ml extraction tube. Next, add 4ml of water, and vortex the sample for 1 min. And then add 10ml of 1% acetic acid acetonitrile and the extraction salt pack.
Shake it vigorously for 1 min, centrifugally rotate at 4000 r/min for 5 min. The upper layer is CH3CN, which will be taken 6ml to a 15ml purification tube in the next phase. Vortex for 1 min and centrifugally rotate at 4000 r/min for 5 min.
Take 4ml of the supernatant to another tube and reconstitute it with 1ml of the mobile phase. After being filtered with the 0.22μm filter membrane, it could be used for the test device.