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WorksheetsInstrumental methods
Total questions: 10
Worksheet time: 20mins
Chromatography is the process for identification, purification, and separation of components of a mixture on the basis of ____________
Difference in their boiling point
Difference in their melting point
Difference in their affinity for mobile and stationary phase
Difference in their solubility
What two factors contribute to how well compounds are separated by chromatography?
Difference in injection times between peaks and the height of the peaks
Difference in elution times between peaks and the width of the peaks
Difference in width between peaks and the height of the peaks
Difference in retention times between peaks and the shape of the peaks
Most of the Analytical Chemistry research is based on quantitative analysis. The chromatographic techniques used for such analysis can have varied resolutions. In the method development stage, all these issues must be resolved prior to method validation and sample analysis. As a chemist what resolution would you think ideal for quantitative analysis?
Resolution is immaterial and the above statement is not correct
Resolution is essential and any value greater than zero would be ok
It depends on the analysis
Resolution must be greater than 1.5 for better results
A band of solute broadens as it moves through a chromatography column. (Refer any Analytical Chemistry text for examples). As a sample is injected it's so narrow but as it moves through the column various shapes might emerge. What is the most acceptable shape used in chemical analysis?
Gaussian and asymmetric
Non Gaussian and symmetric
Non Gaussian and asymmetric
Gaussian and symmetric
During the lecture, we discussed Gas-solid chromatography is not being commonly used. However, the technique evolves as it does have important applications in Chemistry. Identify the best type of compounds it can separate.
Thermally stable organic components
Volatile organic components
Thermally unstable inorganic components
Volatile and low molecular weight species
The mobile phase used in gas chromatography should be inert. However, a research supervisor advised his students to use hydrogen as a carrier gas. It has been studied that none of the components in the sample react with hydrogen gas. Nevertheless, the research supervisor would like to have your opinion about the use of hydrogen over helium as the Environment Health and Safety Manager in the University. Which of the following are the disadvantages of hydrogen over helium, which can be used as carrier gases in gas chromatography?
Dangerous to use and reduced sensitivity
Dangerous and expensive
Flammable and reduced sensitivity
Low thermal stability and high density
The sample injection is the onset of the separation. Therefore, the samples should be introduced very carefully using the correct technique. If the sample is a liquid then which method is used to inject liquid samples into the column?
Gas tight syringe
Micro-syringe
Rotary sample valve
Solid injection syringes
What is the most accurate statement with respect to the gas chromatography separation?
The solute, while moving in the column is always in equilibrium with both the stationary phase and the mobile phase. However, the stationary phase and mobile phase are not in equilibrium.
The solute, while moving in the column is not required to be in equilibrium with both the stationary phase and the mobile phase.
The solute can start to be in equilibrium with both the stationary phase and the mobile phase once the leading sample elutes
None of the above is correct
What do you understand by the term "dead time"?
The time required for all molecules of the sample to pass through the mobile phase
The solute migration time prior to it becomes adjusted retention time
The total retention time that a sample would have
The time required for a molecule of the mobile phase to pass through the column
A solute with a retention time of 407 s has a width at the base of 13.0 s on a column with a length of 12.2 m long. The resolution can be calculated using the number of plates and plate height. Using the equations (Refer Analytical Chemistry text) determine the value of plates and the height for this separation.
15700 and 0.78 m
15700 m and 0.78 mm
15700 and 0.78 mm
Information provided is not sufficient
