Question 1

The chromatographic method based on biologically related interactions by immobilizing one of a pair of interacting biomolecules onto a solid support and placing it in a column is known as:

Accepted Answer

A)  affinity chromatography
B)  ion-suppression chromatography
C)  ion-pair chromatography
D)  gel-permeation chromatographyE) All of the above
F) A) and D)

Question 2

__________ is the most important parameter influencing separation in gas chromatography.

Accepted Answer

A)  carrier gas flow rate
B)  column temperature
C)  injection volume
D)  analyte polarityE) A) and B)
F) A) and C)

Question 3

Combining selected ion monitoring (SIM)  with isotope dilution in electron-ionization mass spectrometry allows:

Accepted Answer

A)  for the removal of extraneous ions that produce complicating peaks in the mass spectrum
B)  for quantification utilizing an internal standard
C)  for confirmation of results obtained by electron-ionization mass spectrometry alone
D)  for quality control checks on the mass spectrometry procedureE) All of the above
F) A) and C)

Question 4

In mass spectrometry, the molecular ion is:

Accepted Answer

A)  the ion of highest relative abundance in the spectrum
B)  the ion from which all other fragment ions are derived
C)  always observed in the mass spectrum
D)  all of the aboveE) B) and C)
F) B) and D)

Question 5

Given that the base peak (m/z = 112)  in a mass spectrum has an initial relative abundance of 75% and the peak at m/z 125 has an initial relative abundance of 30%, what will be the relative abundance of the two peaks following normalization? (answer format: relative abundance for m/z 112, relative abundance for m/z 125)

Accepted Answer

A)  22.5%, 100%
B)  250%, 100%
C)  100%, 22.5%
D)  100%, 40%E) B) and C)
F) C) and D)

Question 6

Which of the following components of the gas chromatograph does not require close temperature control?

Accepted Answer

A)  the carrier gas
B)  the injector port
C)  the column
D)  the detectorE) A) and B)
F) B) and C)

Question 7

Match the following statements with normal-phase chromatography or reversed-phase chromatography.
1) The more polar the mobile phase, the weaker the mobile phase.
2) The more polar the mobile phase, the stronger the mobile phase.
3) The more nonpolar the mobile phase, the weaker the mobile phase.
4) The more nonpolar the mobile phase, the stronger the mobile phase.

Accepted Answer

A)  1 and 4 are correct for normal-phase chromatography
B)  2 and 3 are correct for normal-phase chromatography
C)  1 and 3 are correct for reversed-phase chromatography
D)  2 and 4 are correct for reversed-phase chromatographyE) A) and D)
F) A) and C) B

Question 8

Which of the following is the correct order of sensitivity for HPLC detectors? (most sensitive to least sensitive)

Accepted Answer

A)  absorbance, fluorescence, electrochemical
B)  fluorescence, absorbance, electrochemical
C)  electrochemical, fluorescence, absorbance
D)  absorbance, electrochemical, fluorescenceE) All of the above
F) A) and B)

Question 9

Suppose there is a desire to analyze a series of compounds by gas chromatography because of their similarity in polarity and lack of hydrogen-bonding potential.The compounds of interest are known to have low volatility.How should the technologist proceed?

Accepted Answer

A)  Consider analysis of these compounds by liquid chromatography.
B)  Consider analysis of these compounds by gas chromatography at significantly elevated temperatures.
C)  Consider chemical derivatization of these compounds prior to gas chromatography.
D)  Report that these compounds cannot be analyzed by gas chromatography because of the lack of volatility.E) All of the above
F) C) and D)

Question 10

Which of the following gas chromatographic detectors requires that the analyte be flammable for detection to occur?

Accepted Answer

A)  thermal-conductivity detector
B)  flame-ionization detector
C)  electron-capture detector
D)  mass-spectrometer detectorE) All of the above
F) C) and D)

Question 11

What is meant by the phrase isocratic analysis in liquid chromatography?

Accepted Answer

A)  chromatographic analysis in which the mobile phase composition constantly changes during the chromatographic analysis
B)  chromatographic analysis in which the mobile phase composition remains constant during the chromatographic analysis
C)  chromatographic analysis in which the temperature of the stationary phase constantly changes during the chromatographic analysis
D)  chromatographic analysis in which the temperature of the stationary phase remains constant during the chromatographic analysisE) A) and C)
F) A) and B)

Question 12

Which of the following gas-chromatographic detectors is known to be the least sensitive but the most versatile?

Accepted Answer

A)  thermal-conductivity detector
B)  flame-ionization detector
C)  nitrogen-phosphorus detector
D)  electron-capture detectorE) None of the above
F) A) and B)

Question 13

_____ mass spectrometry is more likely to reveal the molecular weight of the molecule being analyzed, and ______ mass spectrometry is more likely to reveal structural details of the molecule being analyzed._____ mass spectrometry is considered to be the more sensitive of the two techniques by several orders of magnitude.(CI = chemical-ionization; EI = electron-ionization)

Accepted Answer

A)  CI, EI, CI
B)  CI, EI, EI
C)  EI, CI, CI
D)  EI, CI, EIE) A) and B)
F) A) and C) A

Question 14

What is the purpose of adding an amine modifier (such as triethylamine)  to the mobile phase when using a silica-based reversed-phase stationary phase for the chromatography of basic compounds?

Accepted Answer

A)  to help dissolve the basic compounds in the mobile phase
B)  to adjust the pH of the mobile phase to the desired basic pH
C)  to block free silanol sites on the stationary phase from reacting with the basic solutes
D)  to establish a flat baseline for spectrophotometric measurementsE) A) and B)
F) A) and D) C

Question 15

Which of the following identifies a purpose for the use of internal standardization in chromatography?

Accepted Answer

A)  It compensates for loss during sample preparation, injection imprecision, and detector variation.
B)  It allows for analyte quantification.
C)  It serves as a quality-control check.
D)  All of the aboveE) A) and C)
F) A) and D)

Question 16

Which of the following are required characteristics of the carrier gas used in gas chromatography?

Accepted Answer

A)  It must be chemically and chromatographically inert.
B)  It must be pure and dry.
C)  It must be matched with the appropriate gas-chromatographic detector.
D)  All of the aboveE) B) and C)
F) A) and B)

Question 17

Which of the following types of chromatography should be selected to separate relatively large molecules (100,000 D or greater) ?

Accepted Answer

A)  adsorption chromatography
B)  partition chromatography
C)  ion-exchange chromatography
D)  gel-permeation chromatographyE) A) and B)
F) None of the above

Question 18

Suppose there is the need to separate the components of a mixture in which the components are known to have a molecular weight of less than 1000 D, not be ionizable, and be relatively nonpolar with limited hydrogen-bonding potential.Which chromatographic method should be selected?

Accepted Answer

A)  adsorption chromatography
B)  partition chromatography
C)  ion-exchange chromatography
D)  gel-permeation chromatographyE) All of the above
F) C) and D)

Question 19

The three most common HPLC detectors used in the clinical laboratory are absorbance, fluorescence, and electrochemical detectors.What is the most important limitation of these detectors?

Accepted Answer

A)  These detectors will provide semi-quantitative data only.
B)  These detectors will provide preliminary solute identification only.
C)  These detectors will not provide a linear relationship between detector output (e.g., absorbance)  and concentration.
D)  These detectors lack the needed sensitivity to be useful in clinical laboratory analysis.E) A) and C)
F) B) and C)

Question 20

Which of the following techniques is the most advantageous technique for separating enantiomers by chromatography?

Accepted Answer

A)  use of a chiral stationary phase specifically designed for the enantiomeric pair
B)  use of a mobile phase containing a chiral complexing agent which forms diastereomeric complexes during the chromatographic analysis
C)  chemical derivatization of the enantiomeric pair, forming diastereomers prior to chromatographic analysis
D)  chemical derivatization of the enantiomeric pair, forming diastereomers following chromatographic analysisE) All of the above
F) B) and C)

Exam 4: Chromatographic Techniques

The chromatographic method based on biologically related interactions by immobilizing one of a pair of interacting biomolecules onto a solid support and placing it in a column is known as:

Correct Answer
verified

__________ is the most important parameter influencing separation in gas chromatography.

Correct Answer
verified

Combining selected ion monitoring (SIM) with isotope dilution in electron-ionization mass spectrometry allows:

Correct Answer
verified

In mass spectrometry, the molecular ion is:

Correct Answer
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Correct Answer
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Which of the following components of the gas chromatograph does not require close temperature control?

Correct Answer
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Correct Answer
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B

Which of the following is the correct order of sensitivity for HPLC detectors? (most sensitive to least sensitive)

Correct Answer
verified

Suppose there is a desire to analyze a series of compounds by gas chromatography because of their similarity in polarity and lack of hydrogen-bonding potential.The compounds of interest are known to have low volatility.How should the technologist proceed?

Correct Answer
verified

Which of the following gas chromatographic detectors requires that the analyte be flammable for detection to occur?

Correct Answer
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What is meant by the phrase isocratic analysis in liquid chromatography?

Correct Answer
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Which of the following gas-chromatographic detectors is known to be the least sensitive but the most versatile?

Correct Answer
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Correct Answer
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A

What is the purpose of adding an amine modifier (such as triethylamine) to the mobile phase when using a silica-based reversed-phase stationary phase for the chromatography of basic compounds?

Correct Answer
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C

Which of the following identifies a purpose for the use of internal standardization in chromatography?

Correct Answer
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Which of the following are required characteristics of the carrier gas used in gas chromatography?

Correct Answer
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Which of the following types of chromatography should be selected to separate relatively large molecules (100,000 D or greater) ?

Correct Answer
verified

Suppose there is the need to separate the components of a mixture in which the components are known to have a molecular weight of less than 1000 D, not be ionizable, and be relatively nonpolar with limited hydrogen-bonding potential.Which chromatographic method should be selected?

Correct Answer
verified

The three most common HPLC detectors used in the clinical laboratory are absorbance, fluorescence, and electrochemical detectors.What is the most important limitation of these detectors?

Correct Answer
verified

Which of the following techniques is the most advantageous technique for separating enantiomers by chromatography?

Correct Answer
verified

Exam 4: Chromatographic Techniques

The chromatographic method based on biologically related interactions by immobilizing one of a pair of interacting biomolecules onto a solid support and placing it in a column is known as:

Correct AnswerverifiedShow Answer

__________ is the most important parameter influencing separation in gas chromatography.

Correct AnswerverifiedShow Answer

Combining selected ion monitoring (SIM) with isotope dilution in electron-ionization mass spectrometry allows:

Correct AnswerverifiedShow Answer

In mass spectrometry, the molecular ion is:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Which of the following components of the gas chromatograph does not require close temperature control?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedB

Which of the following is the correct order of sensitivity for HPLC detectors? (most sensitive to least sensitive)

Correct AnswerverifiedShow Answer

Suppose there is a desire to analyze a series of compounds by gas chromatography because of their similarity in polarity and lack of hydrogen-bonding potential.The compounds of interest are known to have low volatility.How should the technologist proceed?

Correct AnswerverifiedShow Answer

Which of the following gas chromatographic detectors requires that the analyte be flammable for detection to occur?

Correct AnswerverifiedShow Answer

What is meant by the phrase isocratic analysis in liquid chromatography?

Correct AnswerverifiedShow Answer

Which of the following gas-chromatographic detectors is known to be the least sensitive but the most versatile?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedA

What is the purpose of adding an amine modifier (such as triethylamine) to the mobile phase when using a silica-based reversed-phase stationary phase for the chromatography of basic compounds?

Correct AnswerverifiedC

Which of the following identifies a purpose for the use of internal standardization in chromatography?

Correct AnswerverifiedShow Answer

Which of the following are required characteristics of the carrier gas used in gas chromatography?

Correct AnswerverifiedShow Answer

Which of the following types of chromatography should be selected to separate relatively large molecules (100,000 D or greater) ?

Correct AnswerverifiedShow Answer

Suppose there is the need to separate the components of a mixture in which the components are known to have a molecular weight of less than 1000 D, not be ionizable, and be relatively nonpolar with limited hydrogen-bonding potential.Which chromatographic method should be selected?

Correct AnswerverifiedShow Answer

The three most common HPLC detectors used in the clinical laboratory are absorbance, fluorescence, and electrochemical detectors.What is the most important limitation of these detectors?

Correct AnswerverifiedShow Answer

Which of the following techniques is the most advantageous technique for separating enantiomers by chromatography?

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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B

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A

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C

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