Mixed 1 Flashcards
What is the retention factor (k) sometimes called?
A. Separation factor
B. Capacity factor
C. Selectivity factor
D. Efficiency factor
B. Capacity Factor
Also known as retention factor, it is a convenient descriptor that is dimensionless and independent of flow rate and column dimensions
What is the void volume (V0) also known as?
A. Dead volume
B. Peak volume
C. Flow volume
D. Stationary volume
A. Dead volume
Void volume is also known as dead volume, hold-up volume, and sometimes retention volume of non-retained component
What determines the selectivity (α) of a chromatographic system?
A. The mobile phase composition
B. The ratio of retention factors of two analytes
C. The number of theoretical plates
D. The flow rate
B. The ratio of retention factors of two analytes
Selectivity (α) is determined as the ratio of the retention factors of two analytes, or the ratio of the reduced retention times
Which parameter is used as a measure of chromatographic efficiency?
A. Retention time (tR)
B. Number of theoretical plates (N)
C. Void volume (V0)
D. Retention factor (k)
B. Number of theoretical plates
The number of theoretical plates (N) is used as a measure of chromatographic efficiency
Identify the term: The product of the analyte retention time and the mobile-phase flow rate.
Retention Volume (VR)
Retention volume is calculated as the product of the analyte retention time and the mobile-phase flow rate
Identify the term: The part of the total analyte retention time that the analyte actually spends in the mobile phase moving through the column.
Void time (t0)
Void time (t0) is the part of the total analyte retention time that the analyte spends in the mobile phase moving through the column
Identify the term: The ratio of the distance between two peaks to the average width of these peaks.
Resolution (Rs)
Resolution (Rs) is the ratio of the distance between two peaks to the average width of these peaks
Which of the following components would be eluted with a retention factor equal to zero?
A. Components positively retained on the column
B. Nonretained components
C. Components with maximum retention time
D. Components with minimum peak width
B. Nonretained components
What is the relationship between the number of theoretical plates (N) and the efficiency of the separation?
A. Directly proportional
B. Inversely proportional
C. No relationship
D. Exponentially related
A. Directly proportional
Which parameter is independent of the mobile phase flow rate and column dimensions?
A. Retention time (tR)
B. Retention factor (k)
C. Void volume (V0)
D. Resolution (Rs)
B. Retention factor (k)
Selectivity (α) is primarily dependent on which of the following factors?
A. The nature of the analytes
B. The flow rate of the mobile phase
C. The temperature of the column
D. The length of the column
A. The nature of analytes
Identify the term: A dimensionless chromatographic descriptor that indicates how well a column retains an analyte.
Retention factor (k)
Identify the term: The hypothetical division of a chromatographic column into smaller sections to measure efficiency.
Theoretical Plates
The _______ is the difference between the total retention time and the hold-up time.
Reduced retention time (t’R)
What is the significance of the number of theoretical plates (N) in chromatography?
A. It indicates the flow rate of the mobile phase
B. It measures the efficiency of separation
C. It determines the selectivity of the column
D. It indicates the void volume
B. It measures the efficiency of separation
How is resolution (Rs) in chromatography defined?
A. The distance between two peaks divided by the flow rate
B. The distance between two peaks divided by the average width of the peaks
C. The peak width at half-height divided by the retention time
D. The ratio of the retention factors of two analytes
B. The distance between two peaks divided by the average width of the peaks
Identify the term: The difference between the analyte retention volume and the void volume.
Reduced retention volume (V’R)
Which term describes the analyte’s equilibrium between the stationary and mobile phases in the column?
Plate Theory
Identify the separation mechanism where the stationary phase is a polymer with different pore sizes.
Mechanical entrapment
What is the primary interaction in Normal Phase Liquid Chromatography (NPLC)?
A. Hydrophobic interactions
B. Ionic interactions
C. Polar interactions
D. Mechanical entrapment
C. Polar Interactions
The principle of separation in Reversed Phase Liquid Chromatography (RPLC) is similar to _______.
solvent-solvent partitioning
In Ion-exchange Liquid Chromatography, what is the primary basis for separation?
A. Size differences
B. Charge densities
C. Polarity
D. Hydrophobicity
B. Charge densities
What term describes the characteristic of molecules based on their structure and electron charge distribution?
Polarity
_______ chromatography is used to separate molecules based on size using a polymer with different pore sizes.
Size Exclusion
Which type of chromatography involves a competition between the stationary phase and the mobile phase for different analytes?
A. Adsorption Chromatography
B. Partition Chromatography
C. Ion-exchange Chromatography
D. Size Exclusion Chromatography
A. Adsorption Chromatography
In Ion-exchange Liquid Chromatography, what is the primary basis for separation?
A. Size differences
B. Charge densities
C. Polarity
D. Hydrophobicity
B. Charge densities
Which type of chromatography involves a competition between the stationary phase and the mobile phase for different analytes?
A. Adsorption Chromatography
B. Partition Chromatography
C. Ion-exchange Chromatography
D. Size Exclusion Chromatography
A. Adsorption Chromatography
In Size Exclusion Chromatography (SEC), what is the basis for separation?
A. Polarity
B. Size
C. Charge
D. Hydrophobicity
B. Size
The number of theoretical plates (N) is a measure of _______ in chromatography.
efficiency
Which type of liquid chromatography uses a liquid stationary phase supported by a solid?
A. Normal Phase Liquid Chromatography
B. Reversed Phase Liquid Chromatography
C. Ion-exchange Liquid Chromatography
D. Size Exclusion Chromatography
B. Reversed Phase Liquid Chromatography
In which type of chromatography is the stationary phase an adsorbent?
A. Partition Chromatography
B. Ion-exchange Chromatography
C. Adsorption Chromatography
D. Size Exclusion Chromatography
C. Adsorption Chromatography
Which mode of chromatography separates molecules based on charge densities?
A. Normal Phase Liquid Chromatography
B. Reversed Phase Liquid Chromatography
C. Ion-exchange Liquid Chromatography
D. Size Exclusion Chromatography
C. Ion-exchange Liquid Chromatography
What is the principle of retention in Normal Phase Liquid Chromatography (NPLC)?
A) More polar solutes are preferentially retained or adsorbed on the polar stationary phase.
B) More non-polar solutes are preferentially retained or adsorbed on the non-polar stationary phase.
C) Both polar and non-polar solutes are equally retained.
D) None of the above.
A) More polar solutes are preferentially retained or adsorbed