Sample Preparation Technology – Solid Phase Extraction
Solid phase extraction (SPE) is the use of a solid adsorbent to adsorb a target compound in a liquid sample, which is separated from the matrix of the sample and the interfering compound. Then, it is eluted with an eluent or desorbed by heating to achieve the purpose of separating and enriching the target compound.
Compared with liquid-liquid extraction, solid-phase extraction has many advantages: solid phase extraction does not require a large amount of solvent, which does not cause emulsification during the treatment.
It uses a highly efficient and highly selective adsorbent (stationary phase). Significantly reduces solvent usage and simplifies sample pretreatment while reducing costs. In general, solid-phase extraction costs one-fifth of the liquid-liquid extraction, but the disadvantage is that the recovery and precision of the target compound are slightly lower than the liquid-liquid extraction.
Solid phase extraction is essentially the first liquid chromatographic separation. It can be divided into normal phase (the polarity of the adsorbent is greater than the polarity of the eluent), and the reverse phase (the polarity of the adsorbent is less than Eluent polarity), ion exchange and adsorption.
The adsorbent used in solid phase extraction is the same as the stationary phase commonly used in liquid chromatography, except that it differs in particle size.