Chromatographic Methods: Master the Art of Separation and Analysis

Question 1

In environmental analysis, which application is commonly associated with GC?

Accepted Answer

Measuring volatile organic compounds in air

Answer

Determining pesticide residues in soil

Answer

Analyzing heavy metals in water

Answer

Detecting radioactive isotopes

Question 2

In HPLC, what is the primary role of the mobile phase?

Accepted Answer

Transporting the sample through the column

Answer

Interacting with the stationary phase to separate sample components

Answer

Detecting the separated molecules

Answer

Providing a solid support for the stationary phase

Question 3

In chromatography, which of the following is referred to as the stationary phase?

Accepted Answer

A solid or liquid that remains stationary during the separation process

Answer

The mobile part of the system

Answer

The sample components themselves

Answer

The detector used to identify the separated components

Question 4

In chromatography, what is the primary role of the stationary phase?

Accepted Answer

To interact with and separate the sample components

Answer

To transport the sample through the system

Answer

To detect the separated components

Answer

To enhance the volatility of the sample

Question 5

For GC analysis, which detector is most commonly employed?

Accepted Answer

Flame ionization detector (FID)

Answer

UV detector

Answer

Mass spectrometer (MS)

Answer

Electrochemical detector

Question 6

In GC, what is the purpose of a headspace sampler?

Accepted Answer

To extract volatile compounds from a sample

Answer

To separate the components of the sample

Answer

To detect the separated components

Answer

To calibrate the GC instrument

Question 7

What is the primary advantage of using a tandem mass spectrometer (MS/MS) for chromatographic analysis?

Accepted Answer

Provides detailed structural information about the compounds

Answer

Enhances the sensitivity of the analysis

Answer

Simplifies the complexity of mass spectra

Answer

Allows for isotopic analysis

Question 8

In High-Performance Liquid Chromatography (HPLC), which component acts as the stationary phase?

Accepted Answer

Packed column material

Answer

Mobile phase

Answer

Sample

Answer

Detector

Question 9

In Gas Chromatography (GC), what is the primary purpose of utilizing a guard column?

Accepted Answer

To safeguard the analytical column from contaminants

Answer

To enhance the efficiency of sample separation

Answer

To increase the capacity of the sample

Answer

To minimize backpressure within the system

Question 10

What is the fundamental difference between isocratic and gradient elution techniques in HPLC?

Accepted Answer

Isocratic elution employs a constant mobile phase composition throughout the separation, while gradient elution gradually alters the composition over time.

Answer

Isocratic elution provides superior separation, whereas gradient elution offers greater versatility.

Answer

Gradient elution is more suitable for complex samples, while isocratic elution is better suited for simpler samples.

Answer

Isocratic elution is a faster technique compared to gradient elution.

Question 11

In GC analysis, which type of detector is commonly used for detecting organic compounds?

Accepted Answer

Flame ionization detector

Answer

Mass spectrometer

Answer

UV-Vis detector

Answer

Fluorescence detector

Question 12

What is the primary principle behind the separation mechanism in Size Exclusion Chromatography (SEC)?

Accepted Answer

Separation based on molecular size

Answer

Separation based on polarity

Answer

Separation based on charge

Answer

Separation based on volatility

Question 13

What is the primary advantage of employing a chiral column in HPLC separations?

Accepted Answer

Enhanced separation of enantiomers

Answer

Improved peak shape and resolution

Answer

Increased sensitivity

Answer

Reduced analysis time

Question 14

What is the primary function of a sample loop in GC?

Accepted Answer

To accurately control the sample volume injected

Answer

To introduce the sample into the column

Answer

To vaporize the sample prior to separation

Answer

To separate the sample components based on their boiling points

Question 15

In HPLC, explain the crucial role of the stationary phase in enabling the separation of complex mixtures.

Accepted Answer

The stationary phase provides a stable surface for compounds to interact and separate based on their polarity, molecular size, and chemical functionalities.

Answer

The stationary phase pumps the mobile phase through the column.

Answer

The stationary phase detects the separated compounds as they elute from the column.

Answer

The stationary phase is not required for separation in HPLC.

Question 16

In HPLC, the separation of compounds is primarily based on:

Accepted Answer

Polarity

Answer

Charge

Answer

Size

Answer

Boiling point

Question 17

What is the purpose of using a carrier gas in GC?

Accepted Answer

To transport the sample through the column

Answer

To dissolve the sample

Answer

To ionize the sample

Answer

To react with the sample

Question 18

Which of the following is a limitation of using UV detectors in HPLC?

Accepted Answer

Low sensitivity for certain analytes

Answer

High cost

Answer

Poor selectivity

Answer

Susceptibility to noise

Question 19

What is the primary advantage of using liquid chromatography-mass spectrometry (LC-MS) in analytical chemistry?

Accepted Answer

Identification and characterization of compounds

Answer

Low cost

Answer

Wide applicability

Answer

High sensitivity

Question 20

Which chromatographic technique is most appropriate for separating volatile organic compounds with low boiling points and high vapor pressures?

Accepted Answer

Gas Chromatography (GC)

Answer

High-Performance Liquid Chromatography (HPLC)

Answer

Thin-Layer Chromatography (TLC)

Answer

Supercritical Fluid Chromatography (SFC)

Question 21

In chromatography, what is the primary function of the stationary phase?

Accepted Answer

To provide differential retention of the sample components based on their interactions.

Answer

To generate a signal for detection.

Answer

To carry the sample components through the system.

Question 22

A chromatogram shows two peaks with identical retention times but different peak areas. Which of the following is the most likely explanation?

Accepted Answer

Different concentrations of the same compound in the sample.

Answer

Incomplete separation of the two compounds.

Answer

Two different compounds with identical chemical properties.

Question 23

In Gas Chromatography (GC), what is the primary purpose of the injection port?

Accepted Answer

To introduce the sample into the carrier gas stream.

Answer

To detect the separated components.

Answer

To separate the sample components.

Question 24

What is the key advantage of using a gradient elution in HPLC?

Accepted Answer

To effectively separate compounds with a wide range of polarities.

Answer

To increase the sensitivity of the detector.

Answer

To reduce the analysis time.

Question 25

Which type of detector is commonly used in Gas Chromatography (GC) for the analysis of organic compounds?

Accepted Answer

Flame Ionization Detector (FID)

Answer

Refractive Index detector

Answer

Electrochemical detector

Answer

UV-Vis detector

Question 26

What is the primary function of a guard column in HPLC?

Accepted Answer

To protect the analytical column from contaminants that may be present in the sample or mobile phase.

Answer

To enhance the separation of the analytes.

Answer

To increase the flow rate of the mobile phase.

Question 27

Which of the following statements best describes the concept of 'selectivity' in chromatography?

Accepted Answer

The ability of the stationary phase to differentially interact with and separate analytes based on their specific physicochemical properties.

Answer

The speed at which analytes elute from the column.

Answer

The ability to separate analytes with similar retention times.