Sample interview questions: Can you discuss your knowledge of different types of sample preparation techniques used in analytical chemistry?
Sample answer:
1. Liquid-Liquid Extraction (LLE):
– This technique is used to separate analytes from a liquid sample by transferring them to a different immiscible liquid phase.
– The two liquids are mixed together, and the analytes partition between the two phases based on their relative solubilities.
– The extract containing the analytes is then separated from the original sample and analyzed.
2. Solid-Phase Extraction (SPE):
– SPE is a sample preparation technique that uses a solid sorbent to selectively retain analytes from a liquid or gas sample.
– The sample is passed through the sorbent, and the analytes are retained on the surface of the sorbent while the remaining components pass through.
– The analytes are then eluted from the sorbent with a suitable solvent and analyzed.
3. Gas Chromatography-Mass Spectrometry (GC-MS):
– GC-MS is a sample preparation technique used to separate and identify volatile compounds in a sample.
– The sample is injected into a gas chromatograph, which separates the compounds based on their boiling points.
– The separated compounds are then detected by a mass spectrometer, which identifies them based on their mass-to-charge ratio.
4. High-Performance Liquid Chr… Read full answer