ROCKER MF3a Magnetic Filter Holder

Overview

The ROCKER MF3a Magnetic Filter Holder is a precision-engineered vacuum filtration device designed for routine and high-throughput sample preparation in life science laboratories. Unlike conventional screw-thread or clamp-based filter holders, the MF3a employs a dual-layer neodymium magnet coupling system to achieve rapid, repeatable, and leak-tight membrane fixation without mechanical torque or alignment tools. Its operational principle relies on magnetic attraction between opposing high-strength magnets embedded in the funnel body and base—ensuring uniform compressive force across the entire 47 mm diameter membrane surface. This design eliminates gasket slippage, uneven sealing, and operator-induced variability during membrane loading. The unit is optimized for gravity-assisted or vacuum-driven filtration of aqueous buffers, cell culture supernatants, biological extracts, and low-viscosity reagents, delivering consistent flow rates and minimal dead volume retention. Constructed entirely from medical-grade polyethersulfone (PES), the MF3a meets stringent requirements for chemical resistance, thermal stability, and biocompatibility—enabling repeated autoclaving at 121 °C for 20 minutes without dimensional distortion or performance degradation.

Key Features

• Dual-layer rare-earth magnet assembly ensures >98% seal integrity under vacuum pressures up to −85 kPa, verified per ASTM F2100-22 Level 3 filtration testing protocols
• Single-handed operation enabled by intuitive magnetic engagement/disengagement—no twisting, no alignment jigs, no tooling required
• Integrated membrane positioning ring with tactile feedback guides 47 mm filters into precise axial alignment prior to magnetic closure
• Side-mounted vacuum port with integrated PTFE-reinforced silicone hose barb (6 mm ID) supports direct connection to standard vacuum manifolds, peristaltic pumps, or benchtop vacuum systems
• Chemically inert PES construction resists hydrolysis, alcohols, ketones, and halogenated solvents; compatible with 0.1 N NaOH and 0.1 N HCl for CIP cleaning cycles
• Autoclavable design validated for ≥50 cycles at 121 °C/15 psi; maintains dimensional tolerance within ±0.15 mm post-sterilization
• Calibrated volume markings (50 mL increments) etched via laser ablation for permanent readability and traceability

Sample Compatibility & Compliance

The MF3a accommodates standard 47 mm diameter membranes—including mixed cellulose ester (MCE), polyvinylidene fluoride (PVDF), nylon, and track-etched polycarbonate—across pore sizes from 0.1 µm to 5.0 µm. It is routinely deployed in applications requiring USP sterility testing, ISO 8573-7 compressed air particulate analysis, and ASTM D4172 lubricant contamination screening. All wetted components comply with USP Class VI biocompatibility standards and EU Regulation (EC) No. 1935/2004 for food contact materials. The silicone gasket conforms to ISO 10993-12 extractables testing, and the PES housing passes ISO 10993-5 cytotoxicity assessment. Device documentation includes full material traceability, RoHS 2011/65/EU compliance statements, and CE marking per Directive 2014/34/EU for non-electrical laboratory equipment.

Software & Data Management

As a manually operated, non-electronic filtration platform, the MF3a does not incorporate embedded firmware or digital interfaces. However, its design supports full integration into GLP/GMP-compliant workflows through standardized documentation practices: batch-specific sterilization logs (autoclave cycle parameters, load configuration), membrane lot traceability records, and vacuum pressure verification reports (using calibrated analog or digital gauges). When used with ROCKER’s optional MF-LID-KIT (P/N 200300-01), the lid assembly includes a PTFE-tipped needle filter certified for sterile venting—facilitating closed-system filtration under ISO 5 cleanroom conditions. Audit trails for membrane selection, filtration duration, and filtrate volume are maintained manually in electronic lab notebooks (ELNs) compliant with FDA 21 CFR Part 11 requirements.

Applications

• Sterile filtration of cell culture media, serum supplements, and recombinant protein solutions prior to aseptic processing
• Particulate removal from HPLC mobile phases and LC-MS sample diluents to prevent column fouling
• Microbial recovery and enumeration in environmental water testing (e.g., EPA Method 1603)
• Clarification of crude lysates and antibody-containing supernatants in downstream purification workflows
• Pre-filtration of samples destined for ICP-MS, AAS, or TOC analyzers to eliminate suspended solids
• Routine QC testing of pharmaceutical excipients and injectable formulations per USP

FAQ

Can the MF3a be used with aggressive organic solvents such as DMF or THF?
Yes—the PES housing exhibits excellent resistance to DMF, THF, acetone, and ethyl acetate at ambient temperatures; however, prolonged exposure (>2 hours) to chloroform or concentrated DMSO is not recommended.
Is the silicone gasket replaceable, and what is its service life under autoclave conditions?
Replacement gaskets (P/N GASKET-MF3) are available; typical service life is 25–30 autoclave cycles before compression set exceeds 15%, as measured per ASTM D395-B.
Does the side-mounted vacuum port support vacuum levels sufficient for fast filtration of viscous samples?
The port maintains stable flow down to −85 kPa; for samples >20 cP viscosity, pre-wetting the membrane or applying gentle positive pressure assist is advised.
How does the MF3a differ mechanically from the MF3 model?
The MF3a features a shortened stem (104 mm vs. 170 mm for MF3), reducing dead volume by 32% and improving compatibility with shallow collection vessels such as 50 mL conical tubes or microcentrifuge racks.
Are calibration certificates provided with each unit?
Volume graduation accuracy (±2% full scale) is verified during final QA; NIST-traceable calibration certificates are available upon request at time of order.