Natural Products Extraction Methods Quiz
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Questions and Answers

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?

    <p>Alkaloids.</p> Signup and view all the answers

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

    <p>To freeze-dry the extract.</p> Signup and view all the answers

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

    <p>Petrol.</p> Signup and view all the answers

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

    <p>Density of the solid</p> Signup and view all the answers

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

    <p>Filling the column with solvent</p> Signup and view all the answers

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

    <p>Avoiding inclusion of air bubbles</p> Signup and view all the answers

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

    <p>Gradient elution</p> Signup and view all the answers

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

    <p>Conduct on-column detection directly after developing the chromatogram</p> Signup and view all the answers

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

    <p>Solvent</p> Signup and view all the answers

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

    <p>It allows for division of natural products based on solubility and polarity</p> Signup and view all the answers

    Which statement is true regarding cold extraction?

    <p>Most compounds are extracted except those with limited solubility</p> Signup and view all the answers

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

    <p>The majority of lipophilic and polar compounds can be extracted</p> Signup and view all the answers

    Why is cold extraction considered a soft extraction method?

    <p>It does not involve heating the extract, preserving biological activity</p> Signup and view all the answers

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

    <p>Majority of lipophilic and polar compounds can be extracted</p> Signup and view all the answers

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

    <p>It allows for selective extraction based on solubility and polarity</p> Signup and view all the answers

    Which technique separates compounds based on their polarity?

    <p>High-performance liquid chromatography (HPLC)</p> Signup and view all the answers

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

    <p>The sample must be volatile and have a lower boiling point than the analytes</p> Signup and view all the answers

    Which statement is true regarding the separation mechanism in HPLC?

    <p>Both the stationary phase and mobile phase participate in the separation process</p> Signup and view all the answers

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

    <p>Flame ionization detector (FID)</p> Signup and view all the answers

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

    <p>1 - 5 μL</p> Signup and view all the answers

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

    <p>To separate compounds based on their solubility in different solvents</p> Signup and view all the answers

    Which of the following statements accurately describes the partitioning process?

    <p>It can be carried out sequentially using immiscible solvents of increasing polarity</p> Signup and view all the answers

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

    <p>Water/methanol</p> Signup and view all the answers

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

    <p>Polar water-soluble compounds</p> Signup and view all the answers

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

    <p>Partitioning relies on solubility, while TLC relies on physical interactions with a solid medium</p> Signup and view all the answers

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

    <p>Monoterpenes and phenolics (such as tannins)</p> Signup and view all the answers

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