CoMetro CF-2 Fraction Collector

Overview

The CoMetro CF-2 Fraction Collector is an engineered solution for automated, high-integrity sample collection in preparative liquid chromatography (prep-LC) and open-column chromatography workflows. Designed around a volume-triggered collection principle—supplemented by time- and drop-count-based modes—the CF-2 delivers precise, reproducible fractionation without reliance on external software or proprietary controllers. Its core architecture employs electromechanical actuation of a rotating carousel and precision stepper-motor-driven tube positioning, ensuring minimal carryover and consistent dwell-time control during tube switching. The system operates silently (<35 dB(A)) and consumes <10 W, making it uniquely suitable for cold-room environments where thermal load and condensation must be avoided—a critical requirement for temperature-sensitive biomolecules, natural product isolates, or labile synthetic intermediates. Unlike pressure-driven or peristaltic alternatives, the CF-2 interfaces directly with low-pressure eluent streams (typically <5 bar), eliminating pulsation-induced dispersion and preserving chromatographic resolution during collection.

Key Features

• Mixed-mode triggering: Selectable collection by elapsed time, volumetric displacement (via calibrated flow rate), or discrete droplet count—enabling synchronization with analog UV/VIS detector outputs or digital TTL pulses.
• Low-inertia tube indexing: ≤0.35 sec switching between adjacent 12/13 mm tubes ensures minimal eluent loss and maintains peak integrity during rapid gradient separations.
• Cold-room certified operation: Stable mechanical performance across 0–40 °C ambient range; no internal condensation due to passive thermal design and absence of heat-generating electronics in the fluid path.
• Modular hardware compatibility: Accepts industry-standard tubing (1/16″ OD), integrates natively with Spectra/Chrom 280 UV detectors for real-time peak recognition, and supports optional 3-way divert valves (e.g., part #124849) for peak-only collection under unattended operation.
• Expandable configuration: Optional 4-column adapter (#124876) enables parallel acquisition from up to four independent columns—29 fractions per column—when mounted on the extendable rear bracket (#124874).
• Durable construction: Anodized aluminum chassis and stainless-steel drive components ensure long-term dimensional stability and resistance to solvent exposure common in organic mobile phases (e.g., acetonitrile, THF, chloroform).

Sample Compatibility & Compliance

The CF-2 accommodates a broad range of container formats—including 12/13 mm round-bottom test tubes (174-position rack), 10–11 mm microtubes (116-position), 17/18 mm culture tubes (116-position), and 28 mm flash vials (42-position)—allowing seamless transition between analytical-scale purification and milligram-to-gram prep work. All tube racks are autoclavable and chemically inert. While the CF-2 itself is not a regulated medical device, its operational parameters support GLP-compliant workflows when paired with validated UV detectors and documented SOPs. Data traceability is maintained through manual logbook correlation of fraction numbers, collection timestamps, and corresponding chromatogram retention windows. For environments requiring electronic records, the CF-2’s TTL-compatible trigger inputs allow integration into LIMS or ELN platforms via third-party I/O modules compliant with IEC 61000-4-2 ESD standards.

Software & Data Management

The CF-2 operates as a standalone hardware controller with no embedded firmware or touchscreen interface—eliminating cybersecurity risks, software obsolescence, and validation overhead associated with embedded operating systems. All collection logic is defined at setup via front-panel rotary encoder and LED display: users configure mode (time/drop/volume), threshold values, and tube count limits without dependency on PC software. Trigger signals from UV detectors (e.g., peak height > X mAU) or external timers initiate collection sequences with <10 ms latency. Audit trails are maintained externally: chromatographic data files (e.g., .cdf from Chromelon or Chromeleon) contain embedded time stamps that align directly with fraction number and physical tube location. This architecture satisfies FDA 21 CFR Part 11 requirements for attributable, legible, and contemporaneous records when combined with controlled document management practices.

Applications

• Purification of natural products from plant extracts using silica or reversed-phase flash chromatography.
• Isolation of monoclonal antibody fragments following protein A affinity chromatography.
• Collection of reaction monitoring fractions in flow chemistry setups coupled to inline UV detection.
• High-throughput fractionation in combinatorial library synthesis where solvent compatibility and rapid tube exchange are essential.
• Method development for chiral separations requiring precise cut-point definition based on asymmetric peak shapes.
• Environmental analysis workflows involving EPA Method 8081B or ISO 18856 extract cleanup prior to GC-MS quantification.

FAQ

Can the CF-2 be used with HPLC systems operating above 100 bar?
No—the CF-2 is designed for low-pressure applications (≤5 bar). For UHPLC or high-pressure prep-LC, a pressure-reducing tee or back-pressure regulator must be installed upstream.
Does the CF-2 support programmable variable-volume collection across a single run?
Yes—by configuring multiple sequential time- or drop-based segments via the front panel, users can define distinct collection volumes for peak apexes versus baseline regions.
Is the 4-column adapter compatible with all rack types?
No—it requires the dedicated 174-tube rack (#124853) and must be used with the extendable mounting bracket (#124874) to maintain mechanical alignment across all four columns.
What maintenance is required for long-term reliability?
Annual inspection of stepper motor coupling integrity and periodic cleaning of the tube carousel guide rails with isopropanol; no lubrication is required due to self-lubricating polymer bushings.
Can the CF-2 operate without a UV detector?
Yes—standalone time- or drop-based collection is fully functional without any detector input; the liquid droplet counter provides accurate volumetric estimation when flow rate is stable and calibrated.