The solid-phase extraction device is a physical extraction process including a liquid phase and a solid phase. During the SPE process, the solid phase has a stronger adsorption capacity than the sample mother liquid. When the sample passes through the solid phase extraction column, the analyte is adsorbed on the solid surface, and the other components pass through the column with the sample mother liquid and then remove the analyte with a suitable solvent.
SPE cartridge advantages SPE columns are based on unbound active irregular silica gel (silica based) particles. The main interactions are polar interactions (such as hydrogen bonding). Because silanol groups are ionizable, they can be used as weak cation exchangers in the medium pH range.
1) Anti-cross-contamination and anti-fogging vacuum tank design; 2) Can be equipped with the large-capacity sampler, rapid concentration and drying device, batch processing samples; 3) SPE cartridges have stable quality, high sample recovery, and good precision.
Three steps to install SPE cartridge Throughout the analysis and testing process, pre-treatment is a time-consuming and laborious step, and the demand for consumables such as SPE columns is also ever-changing. However, existing brand SPE columns do not always meet demand. At this time, it is necessary to install columns by yourself.
1. Install the lower screen Take a lower sieve plate with tweezers, place it on top of the empty column tube, and push the sieve plate horizontally to the bottom of the column tube with a push rod.
2. Put packing Keep the column tube vertical, place the long-necked funnel into the column tube, add the required packing to the funnel, gently lift the funnel, and at the same time tap the column tube to make the top surface of the packing flush. Note: 1) The neck of the long-necked funnel must be of sufficient length to be able to access the lower sieve plate; 2) Avoid lifting the funnel to stick to the inner wall of the column tube.
3. Install the upper screen Keep the column tube vertical, take an upper sieve plate, place it on top of the column tube, and push the sieve plate horizontally to the top surface of the packing with a push rod.
Note: When there is a gap between the top surface of the packing and the sieve plate, keep the column tube vertical and tap the outer wall, and push the sieve plate to an appropriate position with a push rod again.
Operation Steps and Precautions of SPE Cartridge
The operation is slightly different for different filler retention mechanisms such as filler retention target compound or retention impurity.
1. For the solid phase extraction operation, the filler retention target compound is generally four steps: Step one: Activation – removing impurities in the column and creating a certain solvent environment. Be careful not to dry up the column throughout the process; Step two: Sample loading – dissolve the sample in a certain solvent, transfer it into the column, and keep the component on the column. Be careful not to flow too fast, take 1 ml/min, maximum not more than 5 ml/min; Step three: Leaching – maximum removal of interference. A complete dry column is recommended at the end of the process; Step four: Elution – elution with a small volume of solvent and collection of the tested substance. Be careful not to flow too fast for one ml/min.
2. For the impurity retention in the filler, the solid-phase extraction operation generally has three steps: Step one: Activation – removing impurities in the column and creating a certain solvent environment. Be careful not to dry up the column; Step two: Sample loading – transfer the sample into the column, where most of the target compound will flow out with the sample base solution and the impurities will remain on the column, so start collecting, and the flow rate is not too fast; Step three: Eluting – eluent the component with a small volume of solvent and collect it and combine the collection solution. Note that the flow rate is not too fast. This situation is mostly used to remove pigments in food or agricultural residue analysis.