GC Headspace Sampler
Heats a sealed vial containing the sample so volatile compounds move into the gas above it, then injects a portion of that gas into the GC. The standard way to test residual solvents without putting the sample matrix into the GC.
- Pharmaceutical
- Packaging
- Food & beverage
- Environmental
- Forensic
Test your Headspace knowledge
Multiple-choice questions
Pick an answer to see whether you are right and why.
Q1. What is injected into the GC from a static headspace sampler?
basicQ2. A solvent has a very low partition coefficient (K) in the sample diluent. This means it:
intermediateQ3. Why are the sample loop and transfer line kept hotter than the vial oven?
intermediateQ4. Peak areas are low and erratic in some sample vials but not others. The most likely cause is:
advanced
Viva questions
Think of your answer first, then open it to compare.
1. Explain how equilibration temperature and time affect a headspace analysis.
Raising temperature lowers the partition coefficient of most solvents, so more moves into the headspace and the response increases. Temperature must stay well below the diluent's boiling point and must not degrade the sample. Equilibration time must be long enough for the response to reach a plateau; this is shown during development by plotting area against time. Standards and samples must get the same temperature and time.
2. What is a matrix effect in headspace analysis and how can you deal with it?
Dissolved sample can change how strongly a solvent is held in the liquid, so the same solvent concentration gives a different headspace response in sample and standard. It is handled by choosing a diluent that dissolves the sample completely, using matrix-matched standards, standard addition, or salting out in aqueous samples, and by proving accuracy with spiked recovery during validation.
Keep every Headspace in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.