Capillary Column
Definition
A fused silica tube 15 to 60 m long with an internal diameter of 0.25 to 0.53 mm and a stationary liquid film 0.1 to 3 µm thick coated on the inner wall. The default column geometry for almost all forensic GC since the 1990s.
Related terms
- Carrier Gas
- The inert mobile phase that sweeps the sample through the column. Helium is traditional and gives the best peak shape on capillary...
- Derivatisation
- A pre-injection chemical step that converts polar, non-volatile or thermally fragile analytes into volatile, GC-friendly derivatives. Silylation with BSTFA is the most...
- ECD
- Electron capture detector. A Ni-63 radioactive source produces a baseline electron current that is reduced when electron-affinic species (halogens, nitro groups, peroxides)...
- FID
- Flame ionisation detector. A hydrogen-air flame ionises C-H bond containing analytes and a collector electrode reads the ion current. Near-universal for organic...
- Headspace GC
- Gas chromatography in which the sample (blood, urine, vitreous) is sealed in a vial, equilibrated at a fixed temperature, and a portion...
Explained in
- Gas-Liquid Chromatography (GLC): Columns, Carriers and DetectorsA fused silica tube 15 to 60 m long with an internal diameter of 0.25 to 0.53 mm and a stationary liquid film 0.1 to 3 µm thick coated on the inner wall. The d...