HPLC System

A high-performance liquid chromatography (HPLC) system pumps a liquid mobile phase through a column at high pressure (up to 400 bar for HPLC, up to 1200 bar for UHPLC). The column contains a stationary phase that interacts differently with different compounds, causing them to elute at different times. A UV-Vis detector (or fluorescence, mass spec, refractive index, etc.) measures compounds as they exit. Used for: pharmaceutical purity testing and QC, pharmacokinetics studies, protein analysis, food safety testing, environmental monitoring, natural product characterisation. The most widely used analytical instrument in pharmaceutical and biochemical research.

Why Agilent Technologies is the benchmark

Agilent 1260 (and its predecessor the 1200 series) is the most widely used HPLC platform in the world. Exceptional reliability, modular design (mix and match components), massive installed base means parts and service are available everywhere. Software (ChemStation/OpenLab) is the industry standard. A used 1260 DAD system from a pharmaceutical lab represents exceptional value.

What to look for

• System configuration: isocratic (simpler, single-channel pump) vs. gradient (binary or quaternary pump for solvent mixing). Gradient is required for most separations.
• Pump type and pressure rating: standard HPLC (up to 400 bar, particles ≥ 3μm) vs UHPLC (up to 1200 bar, sub-2μm particles). UHPLC is faster but requires special columns.
• Detector: UV-Vis (most common, covers most compounds), DAD/PDA (UV-Vis array — gives spectra at every point), fluorescence (high sensitivity for fluorescent compounds), RID (for non-UV-absorbing compounds).
• Autosampler: manual injection is fine for low throughput; an autosampler is essential for batch analysis of >10 samples.
• Column thermostat/oven: improves reproducibility by controlling column temperature. Important for pharmaceutical QC work.
• Data system: Agilent ChemStation/OpenLab, Waters Empower, Shimadzu LabSolutions. Check that the software version is compatible with current OS and that you can obtain a license.
• Age and generation: Agilent 1100/1200 are older but extremely robust. Agilent 1260 is current and still widely used. Waters Alliance is equivalent. Avoid systems > 15 years old without a service history.
• Spare parts availability: for Agilent 1100/1200/1260, parts are readily available. For older Waters 600/2695, check parts availability before buying.

Tips for buying used

• Always request a run — ask the seller to inject a standard sample (caffeine or acetaminophen in methanol/water works) and show you a clean, sharp peak with correct retention time. A system that can't demonstrate this has a problem.
• Check the pump seals and piston condition. Worn piston seals cause pressure fluctuations ('pulsing') visible on the baseline. Seal replacement is $50–150 per pump head but signals wear.
• Inspect the autosampler needle and needle seat for corrosion or blockage. Contamination from previous users is common and can cause carryover between samples.
• Ask for the service history. A pharmaceutical or CRO lab's used HPLC will have been serviced regularly — this is worth paying extra for.
• Verify the software license. HPLC data systems are licensed per computer and per instrument. Getting a legitimate license for Agilent OpenLab or Waters Empower can cost $3,000–8,000 — factor this in.
• Check the column compartment for corrosion, especially if the system was used with buffers or acidic/basic solvents.
• For gradient systems, ask which solvents were used routinely. Systems used with high-salt buffers (common in bio HPLC) need thorough flushing before use with organic-based methods.
• Confirm detector lamp hours for DAD/PDA detectors. Deuterium lamp replacement is $400–600 and typically needed at 1,000–2,000 hours of use.

Budget trade-offs

What you lose: Nothing in the tier below a used Agilent/Waters is worth considering for serious analytical work. The used market for Agilent/Waters is so liquid that there is no need to compromise.

What you keep: A used Agilent 1260 or Waters Alliance performs identically to a new system for the vast majority of HPLC methods. If you need UHPLC speed or LC-MS coupling, that's a different category of instrument entirely.