A liquid chromatograph joined to a mass spectrometer is two instruments sold as one, and most of the decisions a buyer regrets are about the pairing rather than either half. The analyser decides what questions the system can answer, the chromatograph decides how well it answers them on real samples, and the running cost is set by gases, columns and the service contract rather than by the purchase.
An lcms instrument against a standalone chromatograph
A chromatograph with a UV detector reports retention and absorbance, which identifies nothing on its own and quantifies only what absorbs. Adding a mass spectrometer reports mass, and with a tandem analyser a specific fragment transition, which is what makes an assay selective enough to work in plasma, food or waste water at nanograms per litre. The price of that selectivity is a mobile phase that has to be volatile and buffer-free, so a validated UV method rarely transfers without being rewritten.
lcms systems, and which analyser suits the work
A single quadrupole is a mass-selective detector for routine confirmation. A triple quadrupole counts transitions and is the reference for quantitation, which is what regulated bioanalysis and residue work buy. A time of flight or orbital trap gives accurate mass and full spectra, which is what identifies unknowns, reads intact proteins and supports screening against a library. A hybrid puts a quadrupole in front of one of those and does both at a price. Buy the analyser the assays need, not the one the brochure features.
lcms equipment beyond the two boxes
The list around the instruments is longer than it looks: a nitrogen generator or cylinder supply sized for the source, a roughing pump and its oil or a dry alternative, a chiller, an uninterruptible supply, sample preparation from solid phase extraction to a filtration station, and the data system with its licence and its own qualified computer. A laboratory buying its first system should price the gas and the service contract for five years beside the capital, because together they usually exceed it.
lcms instruments and the service contract
Coupled systems are serviced as one and the contract is where the running cost concentrates: preventive visits, source cleaning, pump maintenance, detector and calibration checks, and a response time that decides how long a failed instrument stops the laboratory. Read what consumables the contract includes and what it excludes, since a source part or a detector can be a large unplanned bill. Ask for the uptime the vendor commits to and what happens when it is missed, and whether remote diagnostics are part of it.
What a quote should be broken into
Ask for the quote itemised into the chromatograph with its pump, autosampler and column oven; the analyser with its source and any second source; the data system licence and the computer it is qualified on; installation, operational qualification and any performance qualification; the gas supply and pumps; and the service contract by year. That layout makes two vendors comparable and exposes the two items most often left out of a headline figure, the licence and the qualification documents.
Where a used system makes sense
A previous generation triple quadrupole running a validated routine assay can be excellent value, and the questions are the ones any instrument purchase asks with one addition: whether the vendor still supports the model with parts and software, since a data system that will not run on a supported operating system cannot be qualified. Ask for a performance report on a standard mixture, the source and pump history, and who will decommission, move and reinstall it, which for a coupled system is a specialist job.
Questions people ask about lcms machine
Single quadrupole, triple or high resolution?
Single for confirmation beside a chromatograph, triple for quantitation, high resolution for identifying unknowns and reading intact proteins. The assays decide, not the specification sheet.
What is usually missing from a headline price?
The data system licence, the installation and qualification documents, the gas supply and pumps, and the service contract, which together often exceed the instrument.
Can a UV method be transferred as it is?
Rarely. Non-volatile buffers and ion pairing agents have to come out of the mobile phase first, which changes retention and means the method is rewritten and revalidated.