Medium-pressure columns

It is a chromatography column built to run at pressures above gravity and flash systems but below analytical HPLC, typically from a few bar up to the low tens of bar. The sample passes through a packed bed, and compounds separate as they move through at different rates.

It refers to the working pressure range the column is designed to handle, sitting between the low backpressures of gravity and flash chromatography and the high pressures of analytical HPLC. The rating comes from how the column body and fittings are built.

A pump pushes a liquid mobile phase carrying your sample through a bed packed with a chosen medium. Compounds interact with that medium to different degrees, so they exit the column at different times and separate into fractions.

The catalogue lists preparative chromatography columns, general chromatography columns, protein purification columns, stainless steel and glass-bodied columns, and bioprocess chromatography equipment. The split between steel and glass tracks the chemistry: steel for organic solvents and higher pressures, glass for aqueous buffers where metal contact is a problem.

They handle preparative purification, protein work and bioprocess development where larger sample loads rule out analytical-scale hardware. Applications include isolating useful quantities of a synthetic compound, antibody capture, tagged-protein isolation and the downstream steps of molecular biology and biologics production.

Start with the column bed: its internal diameter and length fix how much material you can process per run, and the pressure rating must match your pump and resin backpressure rather than sit far above or below it. Then pin down the wetted material, steel for preparative organic chemistry or glass and biocompatible polymer for aqueous protein and bioprocess work.

Used listings describe the column as it stands, while refurbished means work has been done on it, which for a column usually means replaced frits, seals or O-rings. On both, read the condition notes for what resin it last held, whether it arrives packed or empty, and the state of the fittings and body.

Prices in the catalogue range from EUR 9 to EUR 150.656, averaging around EUR 4.740. The low end covers single glass columns, spare tubes and fittings, and the high end covers full preparative or bioprocess assemblies.

The names that recur are Cytiva, GE, Acros Organics, Waters and Agilent. Cytiva and the older GE Healthcare lines carry the protein and bioprocess side, Waters and Agilent appear on the preparative and analytical-adjacent side, and Acros Organics sits among the suppliers of columns and consumables.

A warranty is often possible and is arranged in consultation for the specific listing. Because the condition of each used or refurbished unit differs, the notes on that listing carry the weight.

Parts such as frits, seals and spare tubes can be sourced via Questpair. A well-represented brand makes those consumables easier to match to a known column family.

The body itself can last for many years if kept free of corrosion, cracks and pitting, while wear parts like frits, seals and O-rings are replaced over time. A glass body wants inspection around the fittings for chips and cracks, and a steel body wants its threads and wetted surfaces checked for corrosion.

Used and refurbished columns are listed at lower prices than new, so the decision comes down to weighing the condition notes on a specific listing against the saving. Warranty on either is arranged in consultation for that listing.

The Questpair catalogue holds 506 listings from 15 verified suppliers and distributors across 9 countries, in new, used and refurbished condition. You can compare listings there by type, body material and pressure rating.

Both depend on the individual listing and the supplier holding the unit, since stock sits across 15 suppliers in 9 countries. The listing and the supplier are the place to confirm timing before you commit.

Columns are not calibrated in the sense an analyser is; maintenance centres on replacing worn frits, seals and O-rings and keeping the body free of corrosion, cracks and channelled or dried beds. Questpair does not carry out servicing, but replacement parts can be sourced through it.

Preparative columns are the workhorses for isolating gram quantities from a mixture, reached for by chemists and process developers who need wider bores than analytical hardware. Protein purification columns, packed with affinity, ion-exchange or size-exclusion media, are the biology-facing variant used in protein capture, cell culture harvest clarification and downstream molecular biology.

Cytiva and the earlier GE Healthcare lines dominate the protein and bioprocess end, while Waters and Agilent sit alongside them on the preparative side. Because those column and resin families are widely documented, a used unit is easier to compare and its spare parts easier to match against a known method.

The low end of the band is a single glass column, a set of fittings or spare tubes, while the high end is a full preparative or bioprocess assembly with a large bed and the surrounding hardware. Bore, length and the wetted material drive most of that difference, since a wider steel preparative column costs more than a small glass one.