Solid Phase Microextraction (SPME)
Solid Phase Microextraction (SPME) is an innovative and highly sensitive solvent-free sample preparation technique that offers exceptional efficiency for analyzing volatile and semi-volatile compounds. The process is based on the principles of adsorption/absorption and desorption, where a coated fiber is employed to concentrate target compounds directly from the sample. By capturing these compounds onto the fiber's surface, SPME eliminates the need for solvents, making it an environmentally friendly and cost-effective alternative. This technique is widely valued for its ability to provide rapid, accurate, and reproducible results in various analytical applications.
Overview
Solid Phase Microextraction (SPME) Overview
SPME is widely used in environmental, biological, pharmaceutical, food and beverage, flavors and fragrances, forensics, toxicology, and product testing applications. Some typical uses of SPME include:
- Environmental analysis of water and air samples
- Headspace analysis for trace impurities in polymers and solid samples
- Part-per-trillion odor analysis
- Flavor analysis of food products
- Forensic analysis of arson and explosives samples
- Toxicology analysis of blood alcohol and drugs in urine and serum
How Does Solid Phase Microextraction (SPME) Work?
SPME utilizes a fiber coated with an extraction phase—either a liquid polymer, a solid sorbent, or a combination of both. The fiber is housed in a protective needle and attached to a holder resembling a syringe.
When exposed to a sample, the fiber extracts analytes from the sample matrix by partitioning into the stationary phase until equilibrium is achieved. The coating extracts compounds through absorption (for liquid coatings) or adsorption (for solid coatings). After extraction, the fiber is directly inserted into a chromatographic instrument such as gas chromatography (GC) or high-performance liquid chromatography (HPLC) for desorption and analysis. GC desorption is thermal, while HPLC uses a solvent for desorption into the liquid phase.
Advantages of Solid Phase Microextraction (SPME)
SPME combines sampling, isolation, and enrichment in a single step. By controlling the polarity, thickness of the fiber coating, extraction time, and other parameters, SPME ensures consistent and quantifiable results, even with low-concentration analytes.
Additional benefits of SPME include:
- Solvent-free process
- Easy automation
- Non-destructive to samples
- Applicable to nearly all sample types and matrices
- Reusable and cost-effective fibers
- Small fiber size suitable for fieldwork
- Compatibility with both GC and HPLC instrumentation