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Gas Chromatography

Food Analysis Final Exam

What are the sample requirements for GC? Sample must be volatile and can be polar/nonpolar.
Separations in GC occur by _____. partitioning
T or F: Retention time is unique to the compound of interest. False
___ ___ is used to identify a sample component. Retention time
___ ___ is a parameter used to measure the quantity of the sample. Peak area
Give three advantages of GC. High resolution separation, fast analysis, robust and reliable.
What is the purpose of the detector in GC? Recognizes and responds to sample components as they elute from the column.
What are the three heated zones in GC instrumentation? Inlet, column oven, detector
Why is the detector heated in GC? To keep it clean.
What is the most common mode for GC? Split injections
What is the equation for split ratio? Split ratio = (split + column flow)/column flow
A splitless chromatogram is used for ____ analysis. trace
Give three symptoms of a dirty capillary liner. Extraneous peaks, peak tailing of active compounds, loss of active compounds.
The ideal resolution (separation) is a function of what three factors? Capacity, selectivity, and efficiency.
Define GC detector. A device which senses the presence of a component different from the carrier gas, and converts that information to an electrical signal.
What are the four components of a mass spectrometer? Ion source, mass analyzer, detector, and vacuum system.
Retention times with GC/MS are considered ____ data. qualitative
The size of a peak determines what in GC/MS? How much is present
Name the three different approaches for quantification with GC/MS. External standard calibration, internal standard calibration, and area %.
T or F: Three level calibration is a minimum requirement to provide evidence of the linearity of a calibration curve. True
Name three requirements for a good internal standard. The compound is not present in the sample, the compound is stable, the compound is well separated from other sample components, similar properties to analyte.
What is the purpose of solid phase extraction? Pre-separation (eg. eliminate matrix)
Describe SPE. Sample components are separated based on affinity for stationary/mobile phase.
What are the three steps in solid phase micro extraction? Sample preparation, extraction, and desorption.
T or F: The entire sample is analyzed in headspace GC. False
Created by: goberoi
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