chemistry

Headspace Analysis - Gas Chromatography - Analysis of Ethanol in Blood (Forensic Chemistry) Headspace techniques are employed in conjunction with gas chromatography (GC) analysis for certain type of samples. The GC can handle any gaseous sample and any liquid sample that can be vaporized completely and instantaneously before it goes to a proper column for separation. Unfortunately there are many liquid samples (biological, environmental) that cannot be directly injected into the GC. For such samples headspace analysis can be used. The principle underlying GC headspace analysis is that in a sealed vial at constant temperature equilibrium is established between volatile components of a liquid or solid sample in the vial and the gas phase above it – the “headspace” (Fig. I1). After allowing due time for equilibration (normally 15 min.) a portion of the headspace – ambient volume above a sample matrix where the volatile compounds exist in gaseous form at predictable levels - may be ...