WorksheetsHigh-Performance Liquid Chromatography (HPLC)
Total questions: 20
Worksheet time: 10mins
The main advantage of HPLC over conventional liquid chromatography is
Use of volatile solvents
Higher separation efficiency and speed
Lower operating pressure
Use of larger particle size stationary phases
In HPLC, the stationary phase commonly used in reversed-phase chromatography is
Silica gel
Alumina
C18 bonded silica
Ion-exchange resin
Which type of mobile phase is used in reversed-phase HPLC?
Non-polar solvent
Highly viscous solvent
Polar solvent or solvent mixture
Gas
The typical particle size of packing material used in modern HPLC column is
50-100 μm
20-40 μm
10-15 μm
3-5 μm
Which detector is most commonly used in pharmaceutical HPLC analysis?
Flame ionization detector
UV-Visible detector
Thermal conductivity detector
Mass flow detector
The retention time of a compound in HPLC is best defined as
Time taken for an analyte to elute from the column and reach the detector
Time taken for the solvent to pass through the column
Time taken for analyte injection
Time taken for column equilibration
Which parameter directly affects the resolution in HPLC?
Injection volume only
Flow rate, column efficiency, and selectivity
Detector wavelength only
Mobile phase volume
In normal-phase HPLC, the stationary phase is
Polar and hydrophilic
Non-polar and hydrophobic
Ion-exchange based
Chiral
Which of the following causes peak tailing in HPLC?
Low detector sensitivity
Excessive mobile phase flow rate
Secondary interactions between analyte and stationary phase
Short column length
The function of a guard column in HPLC is to
Improve detector response
Reduce solvent consumption
Protect the analytical column from contamination
Increase retention time
Increasing the mobile phase flow rate generally results in
Increased retention time
Decreased analysis time
Increased column efficiency
Improved peak symmetry
Which of the following is a common application of HPLC in pharmaceutical analysis?
Determination of boiling point
Identification of crystal structure
Measurement of melting point
Assay and impurity profiling of drug substance
The primary function of the degasser in an HPLC system is to
Remove particulate matter from the mobile phase
Prevent bubble formation in the pump and detector
Increase mobile phase flow rate
Stabilize column temperature
An autosampler in HPLC is mainly used to
Increase detector sensitivity
Reduce system back pressure
Improve reproducibility of sample injection
Control column temperature
The column oven in HPLC system is used to
Maintain constant column temperature
Increase analyte solubility
Reduce solvent evaporation
Prevent column blockage
Which solvent is most commonly used as an organic modifier in reversed-phase HPLC?
Hexane
Methanol or acetonitrile
Chloroform
Toluene
A photodiode array (PDA) detector allows
Detection of non-chromophoric compounds only
Higher sensitivity than MS detectors
Simultaneous monitoring at multiple wavelengths
Detection of volatile compounds only
Baseline noise in HPLC chromatogram is often caused by
Inconsistent sample preparation
Mobile phase impurities or detector instability
Low column efficiency
Short retention times
Which practice helps prolong the life of HPLC column?
Using unfiltered samples
Operating at maximum pressure
Flushing with appropriate solvents after use
Storing the column dry
In normal-phase HPLC, polar analytes typically
Elute faster than non-polar analytes
Have a shorter retention times
Show stronger interaction with the stationary phase
Do not interact with the stationary phase
