Selection guide
Membrane selection: compatibility, recovery and wetting
Screen materials against the actual fluid and complete flow path, then compare changes in a controlled small-scale trial.
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Describe the fluid before choosing an acronym
Two fluids called a buffer or cleaning solution may contain different salts, solvents or surfactants. Start with composition and temperature to distinguish an aqueous duty from a solvent-containing or gas duty. State both what must be removed and what must remain in the product; particle removal alone does not define a successful separation.
- List constituents, concentration ranges, pH, temperature and maximum contact time.
- Identify proteins, additives or active components that must be preserved.
Evaluate every wetted component
A PES, PTFE, PVDF or nylon label does not qualify the complete assembly. Supports, end caps, housings and seals may impose a different limit, and one membrane can appear in several constructions. Map the supplier data sheet to the exact order configuration before comparing candidates.
- List membrane, support, housing, end-cap and seal materials separately.
- Include processing, flushing and holding conditions in the exposure assessment.
Separate loss from contamination
A lower result can reflect adsorption or unrecovered sample; a new analytical peak may originate from the filter or container. Compare an unfiltered control, a solvent blank through the complete flow path, and the filtered sample using the same collection and analytical method. Visual clarity cannot reveal these effects.
- Calculate recovered target mass using the actual collected volume.
- Compare early and late fractions to see whether loss changes with throughput.
Treat wetting as part of the process
Hydrophobic and hydrophilic describe a surface–liquid interaction, not a universal application guarantee. If prewetting is required, its fluid, displacement and residuals become part of the process. Select a configuration that starts consistently within an approved procedure and does not introduce unacceptable carryover.
- Record the start-up sequence and the transition to stable flow.
- Retain product codes, lot numbers and sample formulations for scale-up.
Common technical questions
Can one membrane cover every solvent?
No. Assess the complete filter against the actual mixture, temperature and exposure time.
Does low binding mean no loss?
No. Hold-up volume, container surfaces and the actual analyte also affect recovery.
Related product approaches
Check materials, configuration and validation documents for the specific model.