GC columns

A GC column is the separation element inside a gas chromatograph: a length of fused silica or metal tubing whose inner wall carries a stationary phase. As a carrier gas sweeps a vaporised sample through it, the column resolves that sample into its component compounds before they reach the detector.

GC stands for gas chromatography, so a GC column is the tube where the actual chromatographic separation happens. The name refers to the separation hardware specifically, not the whole instrument, though some listings bundle the column with a complete system.

A vaporised sample is carried through the column by an inert carrier gas, and each compound in the sample interacts with the stationary phase coated on the inner wall to a different degree. Compounds that interact more strongly move slower, so they separate out and reach the detector at different times, which is how the chromatogram is produced.

The catalogue is dominated by capillary formats, listed under labels such as capillary gas chromatography column, capillary GC column and capillary column. These describe the same class of narrow fused-silica tubing, with differences coming down to bore, film thickness and phase chemistry; some columns also appear under broader headings like gas chromatograph or analytical instrument because they arrive as part of a complete system.

They separate thermally stable, vaporisable compounds before detection, which covers residual solvent testing in pharmaceutical quality control, headspace analysis in biomanufacturing, fatty acid methyl ester quantification in lipidomics, and microbial identification by cellular fatty acid profiling. Any analysis that depends on resolving a vaporised mixture into its components can use one.

Start with the stationary phase your method specifies, because a non-polar and a polar phase separate the same mixture in different orders and a method will not transfer between them without redevelopment. After phase, settle film thickness for your analyte volatility, then internal diameter and length, which trade resolution against run time.

Both are listed below new prices, and for a column, condition matters more than the label. The stationary phase degrades with thermal cycling and exposure to oxygen, so ask what the column has analysed, how many injections it has seen, and whether the ends have been trimmed, since a trimmed column no longer matches its stated length.

Prices in the catalogue range from EUR 32 to EUR 25.827, with the average listing around EUR 2.804. That spread reflects the difference between a bare replacement capillary near the floor and a specialist column bundled with instrumentation at the top, rather than a difference in quality.

The listings here are dominated by Agilent, Agilent Technologies, HP, Supelco and Thermo Scientific. These are makers whose phase chemistries are widely documented, so a column can be cross-referenced against a published method by part number rather than by guesswork.

A warranty is often possible and is arranged in consultation for the specific listing, which matters more on higher-value column packages than on a single consumable capillary. Check the individual listing for what applies to it.

Parts such as ferrules, guard columns and press-fit connectors can be sourced via Questpair where a listing needs completing. Widely used formats from common makers are generally easier to complete than obscure ones.

A GC column is effectively a consumable, and its working life depends on how it has been used rather than its age. Running near the upper temperature limit, exposure to oxygen, and reactive sample matrices all degrade the stationary phase, so a column that has been run hard for years will bleed more and resolve less than its specification suggests.

Used and refurbished columns are listed at lower prices than new, and for a part that is replaced on a schedule, that difference is where most of the saving comes from. If you buy used, weigh the price against the column's history and ask for a test chromatogram; warranty terms are set per listing in consultation, not centrally.

The Questpair catalogue lists 162 GC columns from 10 verified suppliers and distributors across 9 countries. You can compare listings there by brand, type and condition.

Lead time and shipping depend on the individual listing and the supplier offering it, since the catalogue spans 10 suppliers across 9 countries. Check the specific listing for its terms, or contact Questpair, where specialists respond within an hour.

A column is not calibrated in the instrument sense; instead you condition it before use and verify its performance with a test chromatogram against your method. Trimming damaged ends and keeping the column within its temperature limit are the main ways to extend its working life, and note that Questpair does not offer servicing.

Capillary formats dominate the listings, labelled as capillary gas chromatography column, capillary GC column and capillary column, because they deliver the efficiency modern gas chromatography relies on. Method developers in proteomics, lipidomics, environmental analysis and pharmaceutical QC all reach for capillary columns, choosing bore, film thickness and phase to match their specific analytes.

Agilent, Agilent Technologies, HP, Supelco and Thermo Scientific make up most of what is listed. For a buyer, that concentration helps: a column from one of these makers can be matched to a published method by part number, its specification is documented and familiar for comparing used listings, and replacement parts for common formats are easier to source.

The price band spans two orders of magnitude, from EUR 32 to EUR 25.827, and the gap is mostly about what you are buying rather than quality. A bare replacement capillary sits near the floor, while a specialist column supplied as part of an instrument package reaches the top; condition and brand familiarity shift price within that range too.