Immobilized Liquid Extraction (ILE) is an innovative, simple and cost-effective technique and product line for preparing aqueous samples (biological or environmental) for chromatographic analysis.
ILE shares many fundamental principles with traditional liquid-liquid extractions (LLE). In traditional LLE, a compound partitions between two immiscible liquid phases, usually an aqueous sample and an organic solvent, based on its affinity for each of the liquids. ILE separations are very similar; however, the ‘organic solvent’ is instead a thin layer of polymer that is immobilized on the surface of an ILE device.
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Extracting layer is an elastomeric polymer above its glass transition temperature (Tg) that exhibits the extractive characteristics of a liquid toward analytes while maintaining complete physical homology (matrix independence). The extracting layer:
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Is an elastomer that is immiscible in aqueous sample matrices (water, serum, plasma, urine, etc.)
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The “Immobilized Liquid” (extracting layer) is completely non-porous:
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Eliminates problems often encountered with existing methods and technologies (LLE, SPE, SLE) such as the formation of emulsions, analyte breakthrough (sample loss), and clogging
In an ILE extraction, an aqueous sample is directly exposed to the Immobilized Liquid (polymer extracting layer), permitting compounds to partition between the two phases based on their relative affinity for each. Compounds which partition into the Immobilized Liquid are then back-extracted (eluted) into a small amount of GC or HPLC solvent to complete the extraction process. ILE extractions are taken to equilibrium by agitation, use small volumes of solvent and require no continuous human support during extractions.
Benefits
- Simplified extraction procedure
- Sample agitated while in contact with extracting surface until analytes have reached equilibrium across the aqueous matrix and extracting layer
- Sample is removed and replaced by elution solvent (following an optional rinse step)
- Elution solvent is agitated while in contact with analyte-containing immobilized phase until equilibrium is attained. Resulting elution is ready for analysis
- Easy to use
- Few steps
- Non-porous extracting phase (eliminates clogging and sample hold-up)
- No preconditioning
- Immobilized phase stable at full pH range
- Derivatizations may be performed concurrently with back-extraction
- Reduced solvent usage and waste production
- 50-200uL typical elution volumes
- Ability to use solvent of choice
- Reconstitution not required
- Decreased labor costs
- Extractions performed completely with agitation and require no ongoing human attention
- Improved data precision
- Extractions taken to equilibrium with known phase volumes allow predictably and reproducibly efficient extractions
- Eliminate the need for:
- Thermal desorption devices, separatory funnels, SPE cartridges and disks, SPME fibers, sorbent conditioning and an extensive catalog of glassware or support devices
ILE is a suitable replacement for LLE, SPE, SPME, SLE and SBSE. ILE devices are available in both single sample (cap) and high-throughput (well plate and pipette tip) formats.
ILE Products