Quiz on Advanced Instrumental Methods I

Which of the following best describes chromatography?

• A method for determining food acidity

• A technique used to separate and analyze complex mixtures

• A method for heating and cooling food products

• A technique used only for water testing

In liquid chromatography, what role does the mobile phase play?

• It separates components based on their size

• It moves the sample through the stationary phase

• It enhances the sensitivity of the detector

• It maintains the temperature of the column

Which type of chromatography primarily separates molecules based on their size?

• Ion exchange chromatography

• Size exclusion chromatography

• Affinity chromatography

• Partition chromatography

What is the primary mechanism of separation in adsorption chromatography?

• Electrostatic interactions

• Differences in molecular size

• Adsorption of solutes onto a solid stationary phase

• Selective binding with ligands

Which chromatography method is best suited for separating amino acids in food samples?

• Gas chromatography

• Affinity chromatography

• Ion exchange chromatography

• Size exclusion chromatography

A food scientist needs to analyze protein content in a sample. Which chromatographic technique would be most suitable?

• Liquid chromatography

• Affinity chromatography

• Partition chromatography

• Adsorption chromatography

In detecting pesticide residues in fruits, which chromatography method is commonly used for precise separation and identification?

• Partition chromatography

• Liquid chromatography-mass spectrometry (LC-MS)

• Size exclusion chromatography

• Ion exchange chromatography

Why is size exclusion chromatography not ideal for separating small organic molecules in food?

• Small molecules elute too quickly without resolution

• The mobile phase degrades small molecules

• Small molecules interact too strongly with the stationary phase

• The column temperature is incompatible with small molecules

A food analysis report shows incomplete separation of fatty acids using partition chromatography. Which factor should be adjusted to improve the resolution?

• Decrease the column temperature

• Increase the sample injection volume

• Optimize the polarity of the mobile phase

• Use a larger pore size in the stationary phase

During an ion exchange chromatography run, a food chemist observes inconsistent elution times for mineral ions. What is the most likely cause?

• The column was overheated

• The ionic strength of the mobile phase varied

• The sample was injected too slowly

• The stationary phase was degraded