CoMetro CF-2 Fraction Collector for Preparative Liquid Chromatography

Overview

The CoMetro CF-2 Fraction Collector is an engineered solution for automated, high-fidelity fraction collection in preparative liquid chromatography (prep-LC) and open-column chromatography applications. Designed for integration into both commercial and custom-built separation systems, the CF-2 operates on a dual-trigger logic architecture—supporting collection based on real-time drop counting, elapsed time, or user-defined volume thresholds (via calibrated flow rate input). Its core detection mechanism relies on optical drop sensing, enabling precise, non-contact monitoring of eluent droplet formation at the collector outlet. This eliminates mechanical wear associated with contact-based sensors and ensures long-term reproducibility across thousands of collection cycles. The unit is optimized for low thermal load (<10 W power consumption), permitting stable operation inside refrigerated environments (e.g., cold rooms at 4 °C) without condensation buildup—a critical requirement for thermolabile compound isolation and extended unattended runs.

Key Features

• Three independent collection modes: drop-counting (1–9999 drops, 1-drop resolution), timer-based (6 sec–999 min 59 sec, 1-sec resolution), and volume-derived (calculated from system flow rate and collection duration)
• Sub-350 ms tube switching latency for 12/13 mm diameter tubes—minimizing inter-fraction carryover and preserving peak integrity during rapid gradient separations
• Modular rack system supporting up to 174 collection positions; interchangeable racks accommodate 12/13 mm test tubes, 10–11 mm microtubes, 17/18 mm culture tubes, or 28 mm flash vials
• Low-noise stepper-motor-driven carousel and linear actuator assembly—designed for quiet laboratory environments and minimal vibration transfer to connected detectors
• Integrated optical drop counter with adjustable sensitivity threshold—compatible with aqueous, organic, and mixed-solvent mobile phases
• Optional 4-column adapter (CoMetro Part #124876), enabling parallel fractionation from four independent chromatographic columns under synchronized trigger conditions
• Front-accessible service panel and tool-free rack replacement—reducing maintenance downtime and facilitating routine cleaning protocols

Sample Compatibility & Compliance

The CF-2 is chemically inert toward common HPLC and flash chromatography solvents—including acetonitrile, methanol, dichloromethane, ethyl acetate, and hexane—due to its aluminum housing and stainless-steel fluid-path components. It meets CE safety directives and RoHS material restrictions. When operated in conjunction with validated UV-Vis detectors (e.g., Spectra/Chrom 280 series) and configured with optional 3-way divert valves (Part #124849 or #124838), the system supports peak-directed collection workflows compliant with ICH Q2(R2) analytical method validation guidelines. Full audit trail capability—including timestamped collection events, tube position logs, and valve actuation records—is achievable when interfaced with chromatography data systems (CDS) supporting ASTM E2877-19 or FDA 21 CFR Part 11 electronic record requirements.

Software & Data Management

The CF-2 operates as a standalone hardware controller with front-panel keypad and LCD display, eliminating dependency on host PC software for basic operation. For advanced integration, it provides RS-232 and TTL-compatible trigger I/O ports to synchronize with external detectors, pumps, and data acquisition systems. Trigger signals may be sourced from analog UV absorbance thresholds, digital TTL pulses, or software-generated event markers. All collection parameters—including drop count, time window, tube index, and valve state—are logged internally with millisecond-resolution timestamps. These logs can be exported via serial interface for post-run reconciliation with chromatograms in third-party analysis platforms (e.g., Chromeleon, Empower, or OpenLab CDS). Optional firmware updates support enhanced protocol scripting for multi-step fractionation strategies.

Applications

• Purification of natural products and synthetic intermediates in pharmaceutical R&D
• Isolation of monoclonal antibody fragments following protein A chromatography
• Desalting and buffer exchange of oligonucleotides and peptides in biopolymer synthesis
• Automated collection of fractions for subsequent LC-MS structural characterization
• High-throughput fractionation in combinatorial library screening workflows
• Offline two-dimensional chromatography (2D-LC) where first-dimension effluent is collected and re-injected

FAQ

Can the CF-2 operate inside a 4 °C cold room without condensation issues?

Yes—the unit’s thermal design limits internal heat dissipation to <10 W, preventing dew point exceedance under standard cold-room humidity conditions. No internal condensation has been observed during continuous 72-hour operation at 4 °C.
Is the drop counter compatible with viscous mobile phases such as glycerol-water mixtures?

The optical sensor is calibrated for standard LC solvents (viscosity 10 cP), users should validate drop formation consistency and consider time-based collection as a more robust alternative.
Does the CF-2 support GLP-compliant electronic signatures and audit trails?

While the device itself does not host user authentication or digital signature modules, its timestamped event logs—when captured and archived by a 21 CFR Part 11–compliant CDS—fulfill core audit trail requirements for regulated laboratories.
What is the maximum flow rate supported when using the high-flow 3-way valve (Part #124838)?

The valve is rated for continuous operation up to 25 mL/min with 3/32″ tubing connections, maintaining full divert accuracy and seal integrity across pH 2–12 and temperatures up to 40 °C.
Can I retrofit my existing CF-2 with the 4-column adapter?

Yes—the adapter mounts directly to the rear mounting bracket (Part #124874) and requires no firmware modification. Mechanical alignment tools are included for positional calibration across all four column outlets.