The Concept and Basic Principles of Solid Phase Extraction

The Concept of Solid Phase Extraction

Solid Phase Extraction Cartridges (SPE column, or Solid Phase Extraction Cartridges, or SPE cartridges for short) is a sample pretreatment method based on chromatographic separation. It is a sample preparation technology developed in the mid-1980s. It is developed by a combination of liquid-solid extraction and liquid chromatography. The separation, purification, and enrichment of the sample are achieved mainly by the selective adsorption and desorption process of the sample components by the solid phase filler. Mainly used in sample pretreatment of various foods, agricultural and livestock products, environmental samples, and target compounds in biological samples.

Solid Phase Extraction (SPE) is a sample preparation technique in analytical chemistry designed to extract and concentrate target analytes from complex sample matrices. The concept of SPE revolves around the use of a solid sorbent, typically packed into a cartridge or disk, to selectively interact with and retain specific analytes.


The process begins with the loading of the sample onto the solid sorbent, where the analytes of interest selectively adhere to the sorbent material, while unwanted matrix components pass through. This selective retention is achieved through various interactions such as hydrophobic, ion-exchange, affinity, or other chemical interactions, depending on the nature of the sorbent.

After loading, unwanted matrix components are removed through a washing step using specific solvents that elute interfering compounds without affecting the retained analytes. Subsequently, the target analytes are eluted from the sorbent using an elution solvent or a combination of solvents, disrupting the interactions between the analytes and the sorbent.

The eluate, now containing the concentrated analytes, may undergo further concentration through evaporation. The purified analytes are then ready for analysis using various analytical techniques, such as chromatography or spectrometry.

The success of SPE relies on the careful optimization of parameters, including the selection of an appropriate sorbent, fine-tuning sample loading conditions, and choosing optimal wash and elution solvents. By tailoring these parameters, analysts can achieve maximum selectivity, recovery, and reproducibility in their sample preparation process.

SPE finds widespread applications in environmental analysis, pharmaceutical research, clinical studies, food analysis, and more. It offers advantages such as enhanced sensitivity, selectivity, and reduced interference from matrix components in subsequent analytical methods.

Solid Phase Extraction Principle

Solid phase extraction (SPE) is a separation principle using liquid chromatography using selective adsorption and selective elution. The more common method is to pass a liquid sample through an adsorbent, retain the substance to be tested, and then use an appropriate strength solvent to wash away the impurities, and then elute the test substance with a small amount of good solvent. Thereby achieving the purpose of rapid separation, purification, and concentration. It is also possible to selectively adsorb the interfering impurities and let the measured substance flow out, or simultaneously adsorb the impurities and the north side substance, and then selectively elute the test substance with a suitable solvent.

The principle of solid phase extraction is based on the selective retention and subsequent elution of analytes from the solid phase. The main purpose of the solid phase extraction principle is to reduce sample matrix interference and improve detection sensitivity. SPE technology is based on liquid-solid phase chromatography theory. It uses selective adsorption and selective elution to enrich, separate, and purify samples. It is a physical extraction process that includes both solid and solid phases. It can also be approximated. Think of it as a simple chromatographic process.

Solid Phase Extraction Composition:

Solid phase extraction includes a solid phase (solid adsorbent with a certain functional group) and a liquid phase (sample and solvent). The liquid sample passes through a solid phase extraction device (solid phase extraction column, solid-phase extraction membrane, etc.) equipped with a solid adsorbent under the action of positive pressure, negative pressure, or gravity.

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Advantages of solid phase extraction cartridges

  1. Precise speed control, single flow rate 0.01~7ml/min, support large volume injection and positive pressure elution to avoid cross-contamination;
  2. Stepless numerical control operation, LED digital display, light touch button, ergonomics mechanical design;
  3. Corrosion-resistant roof, chassis phosphating, and multi-layer epoxy resin spraying treatment;
  4. The chassis structure is convenient to maintain;
  5. Multi-channel, small column joints resistant to acid, alkali, organic solvents, and oxidant corrosion;
  6. Technical motor, using high-precision numerical control technology, low energy consumption, low noise;
  7. The CNC pump tube adopts the American original long-life pipe.

Work modes of SPE cartridge

1. Target compound adsorption mode: When the sample passes through the SPE column, the functional group of the adsorbent acts on the target compound, the target compound remains on the SPE column, and the sample matrix is discarded.

  • Pretreatment of solid phase extraction column (activated solid phase extraction column)
  • Sample through the column (add sample and pass the solid phase extraction column)
  • Washing (removing impurities)
  • Drying (removing moisture)
  • Elution (elution of target compound)

2. Impurity adsorption mode: When the sample passes through the SPE column, the impurities are adsorbed by the solid phase adsorbent, and the target compound passes through the SPE column and is collected into the container. It is also used as an impurity removal mode and is commonly used in SPE columns for normal phase packing.

The required instrument supplies:

Solid phase extraction device
Nitrogen blower
Vacuum pump

The application of SPE cartridges

  1. Food safety field;
  2. Pharmaceutical research field;
  3. Environmental protection field;
  4. Judicial expertise field.

Silica gel matrix: Currently, the most commonly used adsorbent is still silica gel or bonded silica gel, whose pH range is 2-8. There are many kinds of silicone matrix fillers with the advantage of multiple selectivities.
Non-silica gel non-polar adsorbent: varying degrees of polarity and surface alkalinity, It is mainly used for cleaning and purifying samples of the complex matrix before analysis. SPE cartridges are very popular in analytical laboratories.

You also can choose Reversed Phase C18 SPE Cartridges, SCX SPE Cartridges, SAX SPE Cartridges, Normal Phase PR Grade Florisil SPE Cartridges, and other SPE cartridges from Hawach.