Chromatographic Techniques in Pharmaceutical Analysis: Master the Basics

Question 1

What is the key difference between isocratic and gradient elution in chromatography?

Accepted Answer

In isocratic elution, the mobile phase composition stays the same, while in gradient elution, it changes gradually.

Answer

Isocratic elution is mainly used for analysis, while gradient elution is used for preparation.

Answer

Isocratic elution is more efficient than gradient elution.

Question 2

Which of the following factors does **not** influence the retention time of a compound in HPLC?

Accepted Answer

Injection volume

Answer

Nature of the mobile phase

Answer

Stationary phase particle size

Answer

Column length

Question 3

What is the **primary** purpose of using a derivatisation reagent in GC?

Accepted Answer

Improve analyte volatility and stability

Answer

Enhance analyte stability only

Answer

Increase analyte polarity only

Answer

Reduce analyte viscosity only

Question 4

Which of the following is **not** a stationary phase typically used in TLC?

Accepted Answer

C18 (Reversed-phase)

Answer

Silica gel

Answer

Alumina

Answer

Polyamide

Question 5

What is the **main** advantage of using a mass spectrometer as a detector in HPLC?

Accepted Answer

High sensitivity and structural identification

Answer

Structural identification only

Answer

High sensitivity only

Answer

Quantitative analysis and universal detection

Question 6

What is the **primary** role of the injector in GC?

Accepted Answer

Introduce the sample into the column in a reproducible manner

Answer

Separate the analytes in the sample

Answer

Detect the analytes in the sample

Answer

Amplify the detector signal

Question 7

In paper chromatography, the stationary phase is:

Accepted Answer

Paper

Answer

Solvent

Answer

Sample

Answer

Chromatographic column

Question 8

The separation of compounds in high-performance liquid chromatography (HPLC) is primarily based on differences in their:

Accepted Answer

Polarity

Answer

Size

Answer

Solubility

Answer

Boiling point

Question 9

Which of the following is not a commonly used derivatization technique in gas chromatography (GC)?

Accepted Answer

Extraction

Answer

Silylation

Answer

Esterification

Answer

Alkylation

Question 10

Which of the following detectors is widely used in GC for detecting analytes?

Accepted Answer

Flame ionization detector (FID)

Answer

UV-Vis detector

Answer

Corona discharge detector

Answer

Mass spectrometer

Question 11

In thin-layer chromatography (TLC), the stationary phase is typically in the form of:

Accepted Answer

A solid

Answer

A liquid

Answer

A gas

Answer

A mixture of a solid and a liquid

Question 12

In a chromatogram, the area under the peak produced by a compound is directly proportional to its:

Accepted Answer

Concentration

Answer

Molecular weight

Answer

Polarity

Answer

Solubility

Question 13

In a chromatographic system, the mobile phase refers to the:

Accepted Answer

Component that moves through the system

Answer

Stationary phase

Answer

Sample

Answer

Component that is separated

Question 14

In gas chromatography, the stationary phase is:

Accepted Answer

A solid or liquid coated on an inert solid support

Answer

A solid

Answer

A gas

Answer

A liquid

Question 15

In high-performance liquid chromatography (HPLC), the mobile phase typically consists of:

Accepted Answer

Water, organic solvents, and buffers

Answer

Solids

Answer

Liquids only

Answer

Gases

Question 16

The separation of compounds in chromatography depends on the principle of:

Accepted Answer

Differential distribution between the stationary and mobile phases

Answer

Physical properties

Answer

Chemical reactions

Question 17

In HPLC, which detector is used to detect UV-absorbing compounds?

Accepted Answer

UV-Vis detector

Answer

Mass spectrometer

Answer

Conductivity detector

Answer

Flame ionization detector (FID)

Question 18

Which of the following is a primary quantitative application of chromatography?

Accepted Answer

Determining the concentration of a compound in a sample

Answer

Identifying an unknown compound

Answer

Separating a mixture of compounds

Question 19

The order of elution of compounds in chromatography is primarily determined by their:

Accepted Answer

Relative affinities for the stationary and mobile phases

Answer

Boiling points

Answer

Molecular weights

Question 20

The term 'chromatogram' refers to:

Accepted Answer

A graphical representation of the separation of compounds

Answer

A chemical structure

Answer

A table of data

Question 21

Which of the following is NOT a type of chromatography?

Accepted Answer

Spectrometry

Answer

GC

Answer

HPLC

Answer

TLC

Question 22

What is the stationary phase in HPLC?

Accepted Answer

Column packing

Answer

Mobile phase

Answer

Sample

Answer

Detector

Question 23

What is the purpose of a guard column in HPLC?

Accepted Answer

To protect the analytical column

Answer

To pump the mobile phase

Answer

To separate the sample

Answer

To detect the analytes

Question 24

Which of the following is a disadvantage of GC?

Accepted Answer

Not suitable for thermally labile compounds

Answer

High sensitivity

Answer

Fast analysis time

Answer

Wide range of applications

Question 25

What is the function of the mobile phase in TLC?

Accepted Answer

To carry the sample through the stationary phase

Answer

To separate the sample

Answer

To detect the analytes

Answer

To absorb the sample