Product Description
Empore extraction disks are a unique solid phase extraction product in which a patented 3M process is used to entrap adsorbent particles into a matrix of polytetrafluroethylene (PTFE), forming a thin particle-loaded membrane. The technology results in dense particle loading (90% sorbent/10% PTFE, wt/wt) and uniform particle distribution throughout the membrane for highly efficient mass transfer.
Please see the Empore Technology Section for more detailed information about Empore and solid phase extraction.
Extraction Disk Processing Options
Empore extraction disks work with vacuum or positive pressure and can be used at either full or reduced pressure.
Glass Filtration Apparatus
The Empore extraction disks work with standard laboratory equipment. Two standard vacuum filtration apparatus are shown.
Vacuum Manifold Systems
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One-, three- or six-station manifolds offer efficient extraction approaches. These manifolds allow multiple sample processing and are more stable and compact than a series of single glass filtration setups. Using the manifold, up to six extractions can completed simultaneously, and multiple manifolds can be managed by a single operator.
The manifolds are constructed from corrosion resistant stainless steel. Each is individually controlled by a valve that allows extraction or venting to the atmosphere. The valve stem is PTFE in a chrome-plated brass housing with stop-pins for positioning.
These manifolds are intended for use with standard filtration glassware. The drip tip is positioned to accommodate a variety of elution receptacles such as K-D tubes, straight-wall vials, and 10 mL volumetric flasks.
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Inline Extraction Disk Holders
Another processing option available for 47 mm disks are inline filter holders such as that pictured here. These devices may be used with either positive pressure or vacuum systems.
Automated Workstations
At the time of this publication, two automated systems were known to be commercially available for 47 mm SPE disks:
Horizon Technology Inc
Aura Industries "SPEEDMAN™"
Product Selection
Empore extraction disks are available in a variety of sorbent chemistries to compliment most analytical applications. The following list of available sorbents is organized by the type of extraction. Please see the Sorbent Chemistry Section for more information about the product specifications and applications.
Reversed Phase Extractions:
Mixed Phase Extractions
Ion-Exchange Extractions
Sample Pretreatment Options
- Microbiological growth can be retarded by lowering sample pH to 2
- Empore™ Filter Aid 400 and/or prefiltration may be helpful if the sample contains excessive particulates
- If the sample contains a high concentration of suspended solids, allow the particles to settle (overnight if necessary). Tilting the sample container to allow particulates to settle on one side is suggested to aid in decanting only the liquid portion of the sample. Particulates can be added to the reservoir after most of the sample has been processed.
Performing an Extraction Method
Standard Reversed Phase Extraction Steps for C8, C18, SDB-XC, and SDB-RPS
Disk Washing
For C8 and C18:
Assemble the filtration apparatus with the Empore disk. Wash the disk and apparatus with the final elution solvent to assure the system is free of contaminants that may be soluble in the eluate.
For SDB-RPS and SDB-XC:
To swell the resin and pre-wash the disk, place 10 mL acetone onto the disk surface (see Note). Allow disk to soak for about three minutes. Pull remaining acetone through the disk with vacuum to dry the disk. Repeat using 10 mL isopropyl alcohol.
NOTE: The disk will swell upon addition of acetone. This may cause cosmetic wrinkles; however this will not affect the performance of the disk. An alternative method of pre-swelling the disk is to apply 2-4 mL acetone directly to the surface of the disk prior to clamping the glass reservoir into place.
Disk Conditioning
Proper disk conditioning is critical for a successful extraction. Conditioning prepares the sorbent to interact efficiently with the sample matrix.FAILURE TO CONDITION THE EXTRACTION DISK PROPERLY WILL RESULT IN ERRATIC AND LOW RECOVERIES.
Condition the extraction disk with methanol by pulling most of the methanol through the disk under vacuum (20 in Hg, 0.68 bar). Leave a small amount of the solvent above the surface of the disk. Allow the disk to soak in the methanol for 60 seconds. At this point, the sample may be added directly to the system for extraction. If the sample is not compatible with the methanol, reagent water may be added prior to the sample to keep the disk wet and avoid contact with the solvent. If at any time prior to sample extraction, the disk should become dry, repeat the conditioning steps above.
Sample Extraction
Add the sample to the reservior and apply the vacuum. Flow rate is dependent on the vacuum source, disk diameter and the particulate content of the sample. Recoveries are generally not effected by the flow rate. After extraction is complete, remove as much residual water as possible from the disk, by applying vacuum to dry the disk for 5 minutes. Shorter periods of air drying may be necessary with some semi-volatile analytes.
Sample Elution
Eluting twice with equal volumes of solvent is recommended. Add the first extraction solvent aliquot to the sample bottle rinsing down the sides of the container. Transfer the solvent to the system by pipette, rinsing the glassware and all parts that came in contact with the sample. Apply the vacuum to draw the elution solvent into the disk. Shut off the vacuum and allow the disk to soak in the elution solvent before applying vacuum to collect the eluate. Repeat this process with a second aliquot of eluting solvent. A third aliquot of elution solvent may be used as a final rinse of the system and disk to enhance recoveries.
Other Types of Extractions
General guidelines for the following can be found under the heading "Product Usage" in the Disk Products Section:
Volume Guidelines
The small bed mass of sorbent in the Empore(TM) membrane allows for the use of smaller solvent volumes compared with traditional SPE products. A general guide to solvent volumes for a disk SPE method using reversed phase sorbents (C18, C8, SDB-XC) is listed in the table below.
Each assay will need some further optimization in terms of selecting the best elution solvent (commonly methylene chloride, methanol or acetonitrile).
EPA Methods will require specific reagents, please refer to those methods when using the Empore Disks for agency reporting.
Condition
Optional: |
Methanol
Reagent water |
10 -15 mL
10 -15 mL |
20-30 mL
20-30 mL |
| Sample Load |
Aqueous |
100-1000 mL |
500-2000 mL |
| Elute |
Organic |
10-15 mL |
20-30 mL |
Note: Suggested solvent volumes will vary according to the disk diameter, the amount of filter aid material, the analyte, the analyte's affinity for the chosen sorbent, and the strength of the eluting solvent. A general guide for solvent volumes is to completely cover the disk and bed of filter aid, such that 2 - 3 mm of solvent is above the top surface.
