Introduction to Solid Phase Extraction Technology

Solid phase extraction technology

Solid-Phase Extraction (SPE) is a sample pretreatment technology developed in recent years. It is synthesized by liquid-solid extraction and column liquid chromatography. It is mainly used for sample separation, purification, and concentration.

Conventional liquid-liquid extraction can avoid many problems, such as easy emulsification, incomplete phase separation, lower quantitative analytical recovery, expensive fragile glassware, and large amounts of organic waste. Solid phase extraction can effectively separate the target analyte from the interference component, which can improve the purity and recovery rate of the target analyte, reduce the relative deviation, improve reproducibility, and facilitate more accurate qualitative and quantitative analysis of the target analyte.

SPE technology is a column chromatography separation process. The technology is an integration of liquid-solid extraction and column liquid chromatography. The combination of this technology gets over the disadvantage of the low recovery rate of the analyses by the traditional liquid-liquid extraction method.

Solid phase extraction technology can conveniently process multiple samples at the same time, greatly reducing the workload and operation time of sample pretreatment, and effectively improving work efficiency. Improves the recovery efficiency, makes the separation between the interferer and the analyses more effective, reduces the sample pretreatment process, and is simple to operate, time-saving and labor-saving.

As a fast and efficient sample preparation technique for cleanup and concentration for analysis of HPLC, GC, TLC, UV, IR, Solid Phase Extraction, as we called “SPE”, is also an excellent tool used by most chromatography in the lab nowadays.

Solid phase extraction technology

SPE is well designed to extract, partition, and adsorb one or more components from a liquid phase onto a stationary phase. The principle can be described as that: by an increase in the elution strength of the eluent, an adsorbed substance can be removed from the simple adsorbent perfectly.

Compared to classical liquid-liquid extraction, SPE has lots of Advantages: lower consumption of solvents and sample costs, high consistency of sample handling, more time savings, and specific selectivity. SPE is put into practice by more and more scientists because it can not only extend a chromatographic system’s operation life but lessen the demand for analytical instruments.

In recent years, a large number of national and industry standards for the application of solid-phase extraction technology have been promulgated. And widely used in food safety testing, agricultural product residue monitoring, medical and health, environmental protection, commodity inspection, chemical production, and other fields.

Types of SPE Separation

SPE is typically used for the preparation of liquid samples and for the extraction of difficult or non-volatile samples, as well as for pre-extracting solid samples into solution.
How is the compound adsorbed and retained on the SPE filler?

Reverse phase solid phase extraction (polar liquid phase, non-polar solid phase)

The basic principle of antiphase bonded silica gel is nonpolar interaction. Since the silica gel is only the main body, there is a small part of the presence of silicone methanol, so there are some polar second-order interactions.
Hydrophobic interaction
1. Non-polar-nonpolar interaction
2. Van der Waals force or dispersion force

Normal phase solid phase extraction (non-polar liquid phase, polar solid phase)

Hydrophilic interaction
1. Polarity – Polar interaction
2. Hydrogen bond
3.π – π interaction
4. Dipole-dipole interaction
5. Dipole-induced dipole interaction

Ion exchange extraction

How ion-exchange solid phase extraction preserves a compound depends largely on the pH of the sample and the pretreatment solution. In order to preserve the compound, the pH of the sample should ensure that the functional groups on the analyte and on the silica surface are negatively charged.
1. Charged compounds are electrostatically attracted to the surface of the charged adsorbent
2. Adsorption (the role of compounds and adsorbent materials)
3. Hydrophobic interactions or hydrophilic interactions, depending on the solid phase material you choose.

Hawach offers you a wide range of chemistries, adsorbent types, and sizes, and it is important to choose the right product for your needs and sample properties.

Being used in sample separation and pretreatment, Hawach SPE Cartridges are divided into silica gel, polymer, adsorption type, the special cartridge according to matrix type. The cartridge has three parts: medical PP empty tube, medical PE sieve plate, and a fixed adsorbent.