Inline HPLC Solvent Filter

What is the Inline HPLC Solvent Filter?

An inline HPLC solvent filter is a small filter placed in the mobile phase path to protect the pump and column. It removes particles from solvents and buffers continuously, with inert materials for sensitive analysis.

Overview

The device is a small stainless steel or PEEK housing containing a replaceable frit or membrane, with pore sizes of 0.2–10 µm, fitted between the solvent reservoir and the pump or between the pump and the injector. Stainless steel frits suit general reversed-phase work, while PEEK and titanium are used to avoid metal interaction with analytes or with high-salt mobile phases. A solvent inlet filter with 10 µm porosity sits in the reservoir to stop larger particles, and an inline filter with a finer frit protects the column from pump seal debris. Frits are replaced on schedule, because a clogged frit raises system pressure and can cause pulsation and retention time drift. Inert materials matter for ion analysis, and the filter housing must be rated for the system pressure.

How does it work?

A laboratory filter separates particles from liquid by passing the liquid through a porous membrane with a defined pore size. Particles larger than the pore are retained on the surface or within the structure, while the filtrate passes through. Membrane material determines chemical compatibility and adsorption: PTFE is inert to most solvents and is used for organic mobile phases, PVDF suits aqueous and mixed phases, nylon binds proteins and is used where adsorption is not an issue, and cellulose acetate and PES are used for aqueous and biological solutions. Pore size of 0.45 µm removes most particulates, while 0.22 µm is used for sterilisation by filtration because it retains bacteria. The housing, whether polypropylene syringe filter, a bottle-top unit or a centrifugal device, provides the driving force and the connection. Extractables and hold-up volume are the main performance risks.

What are the key features?

• Stainless steel or PEEK housing
• Replaceable frit or membrane
• Pore size 0.2–10 µm
• Inert path for ion analysis
• Installed before pump or column
• Pressure rated for the system

What are the technical specifications?

A typical inline hplc solvent filter configuration offers housing of Stainless steel or PEEK, filter element of Replaceable frit or membrane, pore size of 0.2–10 µm, location of Before pump or column, pressure rating of Per system, up to 400 bar and wetted materials of SS, PEEK or titanium. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Inline HPLC Solvent Filter is used in mobile phase particle removal, pump and seal protection, column inlet protection and ion and metal-sensitive analysis. Across the wider Filters class, laboratories also deploy it for sample clean-up before HPLC, mobile phase filtration and sterilisation by filtration.

Which standards and certifications apply?

Relevant standards and methods include USP <788> (particulate matter in injections), USP <665> (plastic components and systems), ISO 13485 (medical device quality management), ISO 10993 (biological evaluation of medical devices), EN ISO 11607 (packaging for terminally sterilized devices) and USP <1664> (assessment of drug product leachables). Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Pre-rinse the filter with the solvent or mobile phase when the method is sensitive, because membranes contain extractables such as wetting agents or oligomers that can appear as peaks, especially with LC-MS. Use a filter with a larger pore or a glass fibre prefilter for dirty samples, since a clogged 0.22 µm filter is a common cause of lost samples. Do not use the same filter for different samples if carry-over matters, and never filter a sterile solution into a non-sterile container. Check the pressure rating of syringe filters, because high pressure can burst the housing and release particles. Store filters in their packaging and respect expiry, especially for sterile units. Record lot numbers, since extractables and adsorption can vary between lots.

How do I select the right Inline HPLC Solvent Filter?

Choose an inert housing and pore size suited to the mobile phase, and replace the frit when pressure rises. RFQ: system pressure, mobile phase, analyte sensitivity to metals and fitting type. Provide the mobile phase and metal sensitivity.

How does it compare with other Filters variants?

Choose the membrane by the solvent, the analyte and the purpose. Use PTFE for organic solvents and aggressive chemicals, PVDF or PES for aqueous and mixed phases, and cellulose acetate for aqueous solutions where low protein binding is wanted. Choose 0.22 µm for sterilisation or where microbes must be removed, and 0.45 µm for general particulate removal before chromatography. Match the format to the volume: syringe filters for 1–100 mL, bottle-top units for 100 mL to several litres, disc filters for vacuum or pressure holders, and centrifugal units for small volumes and concentration. Confirm the housing is compatible with the solvent, check hold-up volume for small samples, and ask for extractables data when the method is sensitive. Do not use a filter that adsorbs the analyte, and verify recovery with your compounds.