Solid-Phase Extraction (SPE)
Definition
Sample clean-up in which analytes are retained on a packed bed of bonded silica or polymer, interferences are washed off, and analytes are eluted with a stronger solvent.
- Sorbent
- Packed bed of bonded silica or polymer
- Steps
- Load, wash off interferences, elute with a stronger solvent
- Purpose
- Sample clean-up before instrumental analysis
- Field
- Toxicology and drug analysis extraction chemistry
Common questions
How does SPE reduce matrix interference in toxicology testing?+
Because the analytes are retained on the sorbent while co-extracted proteins, salts and lipids from biological matrices pass through or are removed in the wash step, the final eluate is far cleaner than a crude extract, which reduces ion suppression and baseline noise in downstream chromatography.
What is the difference between reversed-phase and mixed-mode SPE cartridges?+
Reversed-phase cartridges retain analytes mainly through nonpolar interactions with a bonded silica surface, while mixed-mode cartridges combine that with an ionic functional group so both nonpolar and ionisable compounds, such as basic drugs, can be retained and selectively eluted.
Related terms
- Accelerated Solvent Extraction (ASE)
- Extraction of solid matrices at 100 to 200 degrees Celsius and around 1500 psi in sealed stainless steel cells. Also called pressurised...
- Dried Blood Spot (DBS)
- Sampling format in which 50 microlitres of capillary blood is spotted on Whatman 903 paper, dried and shipped at ambient temperature.
- HPTLC
- High-performance TLC with smaller silica particles, automated Camag Linomat band application and densitometric scanning that delivers quantitative results comparable to HPLC.
- Mixed-Mode SPE
- Sorbent that combines reverse-phase and ion-exchange chemistry on the same particle. Strata-X-C, Oasis MCX and Bond Elut Certify are the cation-exchange forms...
- Solid-Phase Microextraction (SPME)
- Solvent-free extraction in which a fused silica fibre coated with a stationary phase is exposed to the sample or its headspace, and...