Natural Products Extraction Methods Quiz

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What is the main advantage of using solvents of different polarities for extraction?

It simplifies the chemical complexity of the biomass in the extract based on the solubility of the components. (correct)
It allows for the extraction of both lipophilic and hydrophilic compounds.
It preserves the stability of the natural products in the extract.
It increases the yield of the extract.

Why should the removal of solvent be carried out immediately after extraction?

To allow for the separation of lipophilic and hydrophilic compounds.
To reduce the cost of the extraction process.
To prevent the degradation of natural products in the extract. (correct)
To increase the yield of the extract.

What is the purpose of storing dried extracts at -20°C?

To reduce the cost of the extraction process.
To separate the lipophilic and hydrophilic compounds.
To increase the yield of the extract.
To prevent the degradation of bioactive natural products. (correct)

What is the most common group of natural products that are extracted using a tailored protocol?

Alkaloids. (B) Signup and view all the answers

What is the purpose of using a lyophilizer for aqueous extracts?

To freeze-dry the extract. (C) Signup and view all the answers

Which of the following is a common non-polar solvent used for lipophilic extraction?

Petrol. (A) Signup and view all the answers

What is the main factor that determines the selection of the method of packing?

Density of the solid (A) Signup and view all the answers

In the 'wet packing' method, what is done before adding dry silica or alumina to the column?

Filling the column with solvent (C) Signup and view all the answers

What is the key precaution mentioned for all the packing methods described in the text?

Avoiding inclusion of air bubbles (D) Signup and view all the answers

Which elution technique involves a continuous change in the composition of the mobile phase over time?

Gradient elution (C) Signup and view all the answers

In chromatography, what is done for colored or fluorescent compounds in terms of detection?

Conduct on-column detection directly after developing the chromatogram (D) Signup and view all the answers

What is added to the silica or alumina in the 'slurry' method before pouring it onto the column?

Solvent (C) Signup and view all the answers

What is the major advantage of cold extraction using sequential solvents of increasing polarity?

It allows for division of natural products based on solubility and polarity (C) Signup and view all the answers

Which statement is true regarding cold extraction?

Most compounds are extracted except those with limited solubility (C) Signup and view all the answers

What is a characteristic of hot extraction using solvents like ethanol or aqueous ethanol mixtures?

The majority of lipophilic and polar compounds can be extracted (C) Signup and view all the answers

Why is cold extraction considered a soft extraction method?

It does not involve heating the extract, preserving biological activity (B) Signup and view all the answers

What makes hot extraction advantageous when using ethanol as the solvent?

Majority of lipophilic and polar compounds can be extracted (A) Signup and view all the answers

How does the use of sequential solvents of increasing polarity benefit cold extraction?

It allows for selective extraction based on solubility and polarity (D) Signup and view all the answers

Which technique separates compounds based on their polarity?

High-performance liquid chromatography (HPLC) (A) Signup and view all the answers

What is the primary requirement for a sample to be analyzed by gas chromatography?

The sample must be volatile and have a lower boiling point than the analytes (C) Signup and view all the answers

Which statement is true regarding the separation mechanism in HPLC?

Both the stationary phase and mobile phase participate in the separation process (D) Signup and view all the answers

Which detector is commonly used in gas chromatography and is universal for organic compounds?

Flame ionization detector (FID) (C) Signup and view all the answers

What is the typical sample size range for gas chromatography analysis?

1 - 5 μL (A) Signup and view all the answers

What is the primary purpose of partitioning in the context of isolation methods?

To separate compounds based on their solubility in different solvents (C) Signup and view all the answers

Which of the following statements accurately describes the partitioning process?

It can be carried out sequentially using immiscible solvents of increasing polarity (B) Signup and view all the answers

Which of the following solvent pairs is NOT mentioned in the text as an example for partitioning?

Water/methanol (D) Signup and view all the answers

What type of compounds are likely to remain in the aqueous layer after partitioning?

Polar water-soluble compounds (D) Signup and view all the answers

Which of the following statements accurately compares partitioning with thin-layer chromatography (TLC)?

Partitioning relies on solubility, while TLC relies on physical interactions with a solid medium (C) Signup and view all the answers

Which of the following pairs of compounds can be effectively separated using partitioning?

Monoterpenes and phenolics (such as tannins) (C) Signup and view all the answers