Master Instrumental Methods of Analysis in Pharmaceutical Chemistry

Question 1

Revised: Which chromatographic technique separates molecules predominantly based on their size and electrical charge?

Accepted Answer

Improved: Capillary electrophoresis

Answer

Gas chromatography

Answer

High-performance liquid chromatography

Answer

Thin-layer chromatography

Question 2

In ultraviolet-visible spectroscopy, which electromagnetic radiation is primarily utilized?

Accepted Answer

Improved: Ultraviolet radiation

Answer

Infrared radiation

Answer

Microwave radiation

Answer

Visible light

Question 3

Revised: Which electrochemical technique measures the current produced by the oxidation or reduction of a substance?

Accepted Answer

Improved: Amperometry

Answer

Conductometry

Answer

Potentiometry

Answer

Voltammetry

Question 4

In gas chromatography, the separation of molecules is primarily governed by which factor?

Accepted Answer

Improved: Boiling point

Answer

Affinity to a stationary phase

Answer

Molecular weight

Answer

Solubility

Question 5

Which spectroscopic technique provides information about the molecular structure of a compound?

Accepted Answer

Improved: Infrared spectroscopy

Answer

Atomic absorption spectroscopy

Answer

Fluorescence spectroscopy

Answer

Nuclear magnetic resonance spectroscopy

Question 6

Which detector in HPLC is commonly employed for detecting compounds that do not absorb UV radiation?

Accepted Answer

Improved: Evaporative light scattering detector

Answer

Fluorescence detector

Answer

Mass spectrometer

Answer

Refractive index detector

Question 7

In potentiometric measurements, what is the primary role of a reference electrode?

Accepted Answer

Improved: Maintaining a stable potential

Answer

Completing the electrical circuit

Answer

Measuring the working electrode potential

Answer

Signal amplification

Question 8

Which factor primarily influences the retention time of a compound during chromatography?

Accepted Answer

Improved: Mobile phase composition

Answer

Column temperature

Answer

Flow rate

Answer

Sample concentration

Question 9

Among the given options, which is NOT a type of mass spectrometer?

Accepted Answer

Gas chromatograph

Answer

Quadrupole

Answer

Time-of-flight

Answer

Ion trap

Question 10

In a high-performance liquid chromatography (HPLC) system, the stationary phase is:

Accepted Answer

C18 column

Answer

Silica gel

Answer

Mobile phase

Answer

Detector

Question 11

Which factor does NOT influence the retention time of a compound during chromatography?

Accepted Answer

Molecular weight of the analyte

Answer

Nature of the stationary phase

Answer

Flow rate of the mobile phase

Answer

Temperature

Question 12

The primary role of an internal standard in quantitative analysis is to:

Accepted Answer

Correct for variations during sample preparation

Answer

Calibrate the analytical instrument

Answer

Identify the analyte of interest

Answer

Enhance the sensitivity of the analysis

Question 13

What is the principle behind ultraviolet-visible (UV-Vis) spectrophotometry?

Accepted Answer

Measurement of the absorption of electromagnetic radiation in the ultraviolet and visible regions

Answer

Separation of compounds based on their mass-to-charge ratio

Answer

Identification of functional groups based on their characteristic infrared absorption bands

Answer

Determination of the structure of a compound based on its nuclear magnetic resonance spectrum

Question 14

What is the primary function of the mobile phase in HPLC?

Accepted Answer

To dissolve the sample and carry it through the column

Answer

To separate the components of the sample based on their polarity

Answer

To react with the sample and produce a detectable product

Answer

To provide a stationary surface for the sample to interact with

Question 15

What is the primary application of nuclear magnetic resonance (NMR) spectroscopy in pharmaceutical analysis?

Accepted Answer

Determination of molecular structure

Answer

Identification of functional groups

Answer

Quantification of drug metabolites

Answer

Analysis of drug impurities

Question 16

Why are calibration standards crucial for accurate analyte quantification using spectroscopic techniques?

Accepted Answer

They compensate for instrument variations, ensuring quantification accuracy.

Answer

They are unnecessary for quantitative analysis using spectroscopic techniques.

Answer

They are primarily used to find the analyte's maximum absorbance wavelength.

Answer

Any compound structurally similar to the analyte can serve as a calibration standard.

Question 17

Which of the following techniques separates compounds based on their size, charge, and/or affinity for a stationary phase?

Accepted Answer

Chromatography

Answer

Electrochemistry

Answer

Mass spectrometry

Answer

Spectroscopy

Question 18

Which type of spectroscopy utilizes electromagnetic radiation to provide insights into molecular structure and bonding?

Accepted Answer

Molecular spectroscopy

Answer

Atomic spectroscopy

Answer

Electrochemical spectroscopy

Answer

Mass spectrometry

Question 19

Capillary electrophoresis separates charged molecules primarily based on:

Accepted Answer

Differential migration in an electric field

Answer

Size exclusion

Answer

Adsorption and desorption processes on a solid phase

Question 20

In gas chromatography, which detector is commonly used for detecting organic compounds?

Accepted Answer

Flame ionization detector

Answer

Electrochemical detector

Answer

Ultraviolet detector

Answer

Conductivity detector

Question 21

What is the primary role of an internal standard in quantitative instrumental analysis?

Accepted Answer

Compensating for variations in sample preparation and instrument response

Answer

Identifying the analyte of interest

Answer

Quantifying the amount of analyte present

Question 22

Which factors can significantly influence the accuracy of instrumental analysis?

Accepted Answer

Calibration, sample preparation, and instrument maintenance

Answer

Only calibration and sample preparation

Answer

Only sample preparation and instrument maintenance

Question 23

Distinguish between qualitative and quantitative analysis.

Accepted Answer

Qualitative analysis identifies compounds, while quantitative analysis determines their amounts

Answer

Quantitative analysis measures amounts, while qualitative analysis identifies compounds

Answer

Both qualitative and quantitative analyses identify compounds