What Are SPE Cartridges?

Solid-phase extraction is based on traditional liquid-liquid extraction. The filler is a general silica-based bonded stationary phase. Based on the SPE solid filler and the target compound in the sample, various forces are generated to separate the target from the sample matrix. The eluent is eluted to achieve the purpose of separating and enriching the target compound. Solid phase extraction is a fast and economical technique for purifying extracts, improving the accuracy and reproducibility of results. So let’s learn more about solid phase extraction cartridges.

Solid-phase extraction cartridges are a versatile and increasingly popular sample preparation technique. Most are used to process liquid samples extraction, concentration, and purification of semi-volatile and non-volatile compounds. In recent years, the application of solid-phase extraction cartridges has developed rapidly, has been widely used in food, environment, pharmaceutical, and other industries, and has become one of the effective means of sample pretreatment and purification. Common solid phase extraction cartridges are divided into three parts: medical polypropylene column tube, porous polypropylene frit (20um), and packing (mostly 40-60um, 80-100um). In order to avoid cross-contamination and ensure detection reliability, SPE columns are usually disposable, featuring reproducibility, consistency of results, better selectivity, and competitive price. You can choose Reversed Phase C18 SPE Cartridges, Ion-Exchange SCX SPE Cartridges, and Normal Phase Silica SPE Cartridges.

Diol SPE Cartridges.png Diol SPE Cartridges Mixed Mode SPE Cartridges

Main functions of SPE cartridges

The main function and purpose of SPE solid phase extraction cartridge: used for sample separation, purification, and enrichment, reducing sample matrix interference, and improving detection sensitivity
1. Removal of matrix interferences
Solid phase extraction is an effective tool to effectively remove interfering substances, thereby ensuring high sensitivity, high selectivity, and stable and reliable HPLC/MS results.
2. Reduce ion suppression
Solid phase extraction can effectively remove the main substances that cause ion suppression in HPLC/MS analysis. Removal of these interferences can improve mass spectral response, thereby lowering the minimum limit of quantification.
3. Enrichment of target analytes
Concentrations of target compounds are often too low to be accurate and quantitative. Solid-phase extraction can enrich selected analytes without enriching for interfering substances.
4. Improve the performance of the analysis system
SPE improves analytical system performance, such as extending analytical column life, reducing system downtime, and maintenance time; minimizing ion suppression, and improving signal response

Operation procedure of SPE cartridges

First of all, we need to know that a sample includes target and interfering substances. The sample passes through the adsorbent to separate the target and interfering substances, leaving the desired interfering substances and discarding the unwanted interfering substances. The general operation procedure of the solid phase extraction cartridge is divided into the following steps.
1. Activated adsorbent
Rinse the SPE cartridge with an appropriate solvent before extracting the sample to keep the sorbent wet and ready to adsorb target or interfering compounds. Different modes of solid phase extraction cartridges use different solvents for activation.
① Weak polar or non-polar adsorbents used in reversed-phase solid-phase extraction are usually rinsed with water-soluble organic solvents, such as methanol, and then rinsed with water or buffer solution. It is also possible to rinse with a strong solvent (such as hexane) before rinsing with methanol to remove impurities adsorbed on the adsorbent and their interference with the target compound.
②The polar adsorbent used in normal-phase solid-phase extraction is usually eluted with the organic solvent (sample matrix) where the target compound is located.
③ The adsorbent used in ion exchange solid phase extraction can be washed with the sample solvent when it is used for samples in non-polar organic solvents; when it is used for samples in polar solvents, it can be washed with water-soluble organic solvents. , and then rinse with an aqueous solution with a suitable pH value containing a certain organic solvent and salt.
In order to keep the adsorbent in the solid phase extraction cartridge wet after activation until the sample is added, about 1 ml of the solvent for activation should be kept on the adsorbent after activation.
2. Sample loading
Pour the liquid or dissolved solid sample into the activated solid-phase extraction cartridge, and then use the vacuum, pressurization, or centrifugation to make the sample enter the adsorbent.
3. Washing and Elution
After the sample enters the adsorbent and the target compound is adsorbed, the weakly retained interfering compound can be washed away with a weaker solvent, and then the target compound can be eluted with a stronger solvent and collected. Rinse and Elution As previously described, the eluent or eluent can be passed through the adsorbent by means of vacuum, pressure, or centrifugation.
If the adsorbent is selected to have weak or no adsorption to the target compound and strong adsorption to the interfering compound, the target compound can also be rinsed and collected first, while the interfering compound is retained (adsorption). ) on the adsorbent, the two are separated. In most cases, the target compound is retained on the adsorbent and then eluted with a strong solvent, which is more conducive to the purification of the sample.