A refurbished HPLC stack can cost 40–70% less than new — or it can be someone else’s problem shipped to your lab. The difference is entirely in what you verify before paying. Here is the due-diligence checklist we apply on our own bench, module by module, and the questions that separate serious sellers from box-shifters.
System-level questions first
- Was the system tested assembled and flowing, or are these modules “powered on” individually? A pump that runs dry on a bench tells you almost nothing.
- Is there a documented test report — pressure stability, flow accuracy, detector baseline — or only photographs?
- What is the actual configuration (order codes, detector cell type, firmware) versus what your method requires? Confirm software/driver compatibility with your CDS (LabSolutions, Chromeleon, OpenLab) before purchase, not after.
Pump (the heart, and the usual weak point)
- Demand a pressure-hold or flow-accuracy test result. Worn plungers and check valves show up as pressure ripple and drift.
- Ask when seals and plungers were last replaced — on a properly refurbished pump the answer is “during refurbishment, here is the parts list.”
- Listen for check-valve chatter on a video of the pump running against back-pressure.
Detector
For UV/PDA: lamp hours matter — a deuterium lamp is a consumable with roughly 1,000–2,000 useful hours. Insist on the current lamp-hour counter reading and budget a new lamp if it is high. Ask for a baseline noise/drift measurement with flowing mobile phase; a dirty or scratched flow cell hides in photos but not in a baseline.
Autosampler and injector
Needle, seat, and rotor seal condition — these wear parts cause carryover and area-precision failures. Were they replaced? Ask for an injection-precision result (%RSD over replicate injections) if the seller claims full testing — it is the single number that proves an autosampler.
Column oven and degasser
Ovens rarely fail but verify temperature accuracy was checked; degasser vacuum chambers age — ask whether vacuum level was measured.
Paper trail and commercial terms
- Serial numbers photographed and matching the listing (protects you on arrival).
- Clear statement of what warranty or DOA protection applies, and who pays return freight if a module arrives faulty.
- For regulated labs: will the seller support IQ/OQ documentation needs, or at least provide the test data your validation package can reference?
Red flags that should end the conversation
- “Untested, from a working environment” pricing dressed up as refurbished.
- No module serial numbers in photos, or stock photos instead of the actual unit.
- Seller cannot tell you which firmware is installed or which software it was tested against.
Every HPLC system PLC North sells is tested assembled and flowing, with pump pressure, detector baseline, and injection checks documented in the listing. Ask us for the test data on any system — if we have not measured it, we will say so plainly. Browse our tested HPLC systems.