Chromatography & Separation

Buying guide

Price across this field stretches further than on any single category, because the listings run from a replacement part to a complete analytical suite. At the low end sit consumables and accessories, fittings, a single column, a length of tubing, where prices start at EUR 1. At the high end sit complete UHPLC instruments with autosampler, pump stack and mass detector, reaching EUR 244.724. The expensive figures belong to the detection and pumping end of the liquid train, where high-pressure hardware and sensitive detectors carry most of the cost; columns and collectors sit well below them.

Condition weighs heavily here. 96 percent of the listings are used. For a field where instruments are built to run for many years and are routinely serviced, a used pump or detector is a normal purchase rather than a compromise, and the lower price against a new unit is often the whole reason to buy on a marketplace. Used and refurbished systems are listed below new pricing, which is the one comparison worth making directly; where a buyer has to weigh the two, the deciding factors live in the individual listing, and warranty is arranged in consultation for that specific unit.

A practical point for anyone assembling rather than replacing: because the parts are listed separately, a working system can be built from a used instrument plus a new column and fresh consumables, which keeps the sensitive, replaceable part fresh while the durable hardware carries the saving. Parts can be sourced via Questpair when a listing arrives incomplete.

Types of Chromatography & Separation

This field draws on several equipment classes that rarely work alone: HPLC and UHPLC systems, gas chromatographs, FPLC and GPC instruments, ion chromatographs, and the columns, pumps, detectors, autosamplers and fraction collectors that complete them. Chromatography runs as a sequence, sample in at one end and separated fractions or a chromatogram out at the other, and the stages below follow that order. Where two stages constrain each other, that is where the equipment choice actually binds.

Choosing the phase: gas or liquid?

The first decision is whether the analyte will travel in a gas stream or a liquid one, and it is made by the sample, not by preference. Volatile, thermally stable compounds separate in a gas chromatograph, where a carrier gas carries them through a heated capillary column. Everything else, which is most of what a life sciences lab handles, goes into liquid chromatography. That split decides the whole downstream train: a GC system needs an injector, an oven and a flame or mass detector, while a liquid setup needs a high-pressure pump, a packed column and an optical or electrochemical detector. The two share almost no hardware, which is why the catalogue lists them as separate classes and why a lab committed to one rarely buys into the other.

Building the liquid train: pump, column, detector

Within liquid work the pressure regime sets the equipment. Conventional HPLC runs to a few hundred bar; ultra-high-pressure instrumentation pushes well beyond that, driving smaller particles for sharper peaks and faster runs. A pump rated for one is not interchangeable with the other, and neither are the columns, so the choice at the pump end commits the column end. The column itself is where the separation happens: reversed-phase, ion exchange and size-exclusion media each sort molecules on a different property, and the Questpair catalogue carries columns and chromatography media as their own listings so a worn column can be replaced without the instrument. After the column sits the detector, and here the pairing matters: a UV detector needs an analyte that absorbs, while a conductivity detector suits the ion chromatography that handles charged species a UV cell cannot see.

What happens to what comes off the column?

Analytical and preparative separation diverge at the outlet. Where the goal is a chromatogram, the detector signal is the product and a data system records it. Where the goal is purified material, as in FPLC protein work or GPC polymer fractionation, the eluent itself is the product and a fraction collector routes each peak into its own vessel. That changes what the rest of the train must do: a preparative run needs wider columns, higher flow and a collector timed to the detector, so a system built for analysis does not simply scale up. Automation sits across both: autosamplers feed a queue without an operator, and the chromatography data systems listed here turn the detector trace into integrated, reportable peaks. These are the pieces that connect the stages, and on a category page each is described alone; the point here is which ones have to agree.