What are the benefits of decreasing the column internal diameter?
Answer: Increased resolution
Helium is generally preferred as carrier gas over nitrogen and hydrogen because
What does the selectivity factor describe?
Answer: The relative separation achieved between two species
Theoretical plates are used to
Answer: estimate the efficiency of a column
Split injection is carried out by
Answer: splitting off some of the sample so that it does not enter the column
Headspace analysis is carried out in order to
Answer: analyse volatile compounds from solid or liquid samples
Which of the following detectors give mass flow-dependent signals?
Answer: Field ionisation detector
retention gap is placed between the injector and the front of the column to
Answer: retain contaminants and prevent them from reaching the column
In column switching chromatography
Answer: compounds trapped on one column are eluted to another column
Which of the statements is correct?
Derivatisation of a sample is carried out to
Resolution is proportional to the
Answer: square root of the number of theoretical plates in a column
What is the typical internal diameter of fused silica capillary columns?
What useful information can be found from a Van Deemter plot?
Answer: Optimum mobile phase flow rate
Which of the following detectors give concentration-dependent signals?
The GC trace obtained after an experiment is called a
Which of these effects result from slow injection of a large sample volume?
Answer: Decreased resolution
Which of the following is not used for detection in GC?
Sample retention in the column is measured by
Column bleeding occurs when
Answer: traces of the stationary phase are eluted