Question 1

In partition chromatography,separation is based on:

Accepted Answer

A)   hydrogen bonding and hydrophobic interactions.
B)   the molecular size of solutes in a solution and the size of the pores on the beads.
C)   the ability of one component immobilized on a stationary phase to capture specific molecules in the mobile phase.
D)   the differences in the relative solubility of compounds between the stationary and mobile phases.E) A) and D)
F) None of the above

Question 2

A measure of peak separation in a chromatographic method that equals the difference in retention time for two components divided by the average of their peak widths is the definition of:

Accepted Answer

A)   retention factor.
B)   derivatization.
C)   resolution.
D)   affinity.E) B) and C)
F) All of the above

Question 3

Which one of the following improvements could be made to increase the chromatographic (separation) efficiency of a poorly resolved HPLC separation?

Accepted Answer

A)   Using a shorter column
B)   Changing the composition of the mobile phase
C)   Using smaller particles in the stationary phase
D)   Increasing the dead volumeE) A) and B)
F) A) and C)

Question 4

In the thin layer chromatography procedure for drug screening,the retention factor (Rf) value for a compound is given by the:

Accepted Answer

A)   ratio of distance moved by the unknown solute to distance moved by the solvent in the mobile phase.
B)   rate of movement of the mobile phase through the adsorbent compared with standards and controls.
C)   measurement in centimeters of the distance the solute moved in the mobile phase from the point of application.
D)   distance moved by the mobile phase front from the point of application compared with a control.E) All of the above
F) C) and D)

Question 5

A toxicology screen is set up using thin layer chromatographic plates.Four positive controls/standards are used with the following distance of migration from application point results: Std A = 8 cm; Std B = 15 cm; Std C = 22.The acetone solvent front moved 35 cm.After processing an unknown sample,a solute had a migration distance of 16 cm.What are the retention factors (Rf) of standards A,B,and C?

Accepted Answer

A)   8,15,22
B)   8,12,18
C)   4.4,2.3,1.5
D)   0.23,0.43,0.63E) B) and C)
F) A) and C)

Question 6

A toxicology screen is set up using thin layer chromatographic plates.Four positive controls/standards are used with the following distance of migration from application point results: Std A = 8 cm; Std B = 15 cm; Std C = 22.The acetone solvent front moved 35 cm.After processing an unknown sample,a solute had a migration distance of 16 cm.What is the Rf of the unknown solute?

Accepted Answer

A)   0.23
B)   0.45
C)   1.94
D)   16E) B) and D)
F) B) and C) B

Question 7

Some analytes must be derivatized to increase their column retention or detectability.Derivatization means:

Accepted Answer

A)   altering the chemical structure of the analyte to an isomeric form to increase detection and specificity.
B)   adding fluorescent labels or combining the analyte with chiral reagents or other chemicals to increase detectability.
C)   removing dissolved gases in the solvent to produce a clear chromatogram.
D)   using multiple detectors to assist in identification.E) All of the above
F) B) and C)

Question 8

In the isolation of nucleic acids from blood samples,a step is typically performed to separate large molecules,such as proteins and nucleic acids,from smaller molecules such as salts.Which type of separation mechanism would best be suited for this task?

Accepted Answer

A)   Ion exchange
B)   Affinity
C)   Partition
D)   Size-exclusionE) A) and B)
F) A) and C)

Question 9

The type of separation mechanism for chromatography that involves,as one example,use of immunologic principles is _____ chromatography.

Accepted Answer

A)   ion exchange
B)   affinity
C)   partition
D)   adsorptionE) None of the above
F) A) and C) B

Question 10

In clinical applications using gas chromatography,which one of the following column temperature techniques will cause the more volatile analytes to elute first and therefore produce the best separation of complex mixtures of analytes with a range of volatilities?

Accepted Answer

A)   Isothermal operation
B)   Refrigerator (4° to 8° 
C)  temperature operation
C)   Temperature programmed operation
D)   Room temperature operationE) All of the above
F) C) and D)

Question 11

In HPLC,analyte detectors can consist of fluorometers,photometers,and electrochemical detectors.An electrochemical detector measures an electroactive analyte by:

Accepted Answer

A)   monitoring the current that is generated by oxidation or reduction reaction under a constant potential voltage and that is proportional to the concentration of analyte.
B)   measuring an electrical potential difference between two electrodes.
C)   measuring the radiant energy given off when the chemical bonds of an element are dissociated and the element is placed in a ground or atomic state.
D)   measuring both an alteration in enzyme level and a redox reaction at a potentiometric ion-specific electrode.E) A) and C)
F) None of the above

Question 12

You are preparing placental tissue for separation and isolation of a specific enzyme.The enzyme has a negative charge,so you want to use chromatography to perform your task.Which one of the following chromatographic separation mechanisms would be most useful?

Accepted Answer

A)   Ion-exchange
B)   Partition
C)   Affinity
D)   AdsorptionE) None of the above
F) A) and B)

Question 13

Examine the following HPLC chromatograms,both of which were obtained from the same sample: A B
C:\Users\User\Dropbox\Quizplus Parsing Documents\To Be Parsed\Not Complete Tables\Chemistry\TB1858,Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics 7th Edition by Carl A.Burtis PhD\TB1858,Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics 7th Edition by Carl A.Burtis PhD\Images\C616(12) _2.jpg
Which chromatogram has the best resolution because of increased separation or chromatographic efficiency?

Accepted Answer

A)   Chromatogram A
B)   Chromatogram BC) A) and B)
D) undefined A

Question 14

In column chromatography,analytes are identified by their retention times.

Accepted Answer

A) True 
 B)False

Question 15

A type of detector used in GC that is universal in its detection of compounds but has low sensitivity compared with other detectors is a(n) _____ detector.

Accepted Answer

A)   flame ionization
B)   thermal conductance
C)   electron capture
D)   photoionizationE) All of the above
F) B) and D)

Question 16

What component of an HPLC introduces an aliquot of sample into the column and how is this introduction accomplished with the high pressure in the flow path?

Accepted Answer

A)   A syringe is used with a flexible tip placed into the flow path.
B)   A flame ionizes the sample and sprays it into the column.
C)   A flexible septum is coated with sample and placed in the column.
D)   A fixed-loop injector with a switching valve moves the sample into the flow path.E) A) and C)
F) All of the above

Question 17

Thin layer chromatography is a type of planar chromatography with separation based on the principles of partition chromatography.

Accepted Answer

A) True 
 B)False

Exam 12: Chromatography

In partition chromatography,separation is based on:

Correct Answer
verified

A measure of peak separation in a chromatographic method that equals the difference in retention time for two components divided by the average of their peak widths is the definition of:

Correct Answer
verified

Which one of the following improvements could be made to increase the chromatographic (separation) efficiency of a poorly resolved HPLC separation?

Correct Answer
verified

In the thin layer chromatography procedure for drug screening,the retention factor (R_f) value for a compound is given by the:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Some analytes must be derivatized to increase their column retention or detectability.Derivatization means:

Correct Answer
verified

In the isolation of nucleic acids from blood samples,a step is typically performed to separate large molecules,such as proteins and nucleic acids,from smaller molecules such as salts.Which type of separation mechanism would best be suited for this task?

Correct Answer
verified

The type of separation mechanism for chromatography that involves,as one example,use of immunologic principles is _____ chromatography.

Correct Answer
verified
B

In clinical applications using gas chromatography,which one of the following column temperature techniques will cause the more volatile analytes to elute first and therefore produce the best separation of complex mixtures of analytes with a range of volatilities?

Correct Answer
verified

In HPLC,analyte detectors can consist of fluorometers,photometers,and electrochemical detectors.An electrochemical detector measures an electroactive analyte by:

Correct Answer
verified

You are preparing placental tissue for separation and isolation of a specific enzyme.The enzyme has a negative charge,so you want to use chromatography to perform your task.Which one of the following chromatographic separation mechanisms would be most useful?

Correct Answer
verified

Correct Answer
verified
A

In column chromatography,analytes are identified by their retention times.

Correct Answer
verified

A type of detector used in GC that is universal in its detection of compounds but has low sensitivity compared with other detectors is a(n) _____ detector.

Correct Answer
verified

What component of an HPLC introduces an aliquot of sample into the column and how is this introduction accomplished with the high pressure in the flow path?

Correct Answer
verified

Thin layer chromatography is a type of planar chromatography with separation based on the principles of partition chromatography.

Correct Answer
verified

Exam 12: Chromatography

In partition chromatography,separation is based on:

Correct AnswerverifiedShow Answer

A measure of peak separation in a chromatographic method that equals the difference in retention time for two components divided by the average of their peak widths is the definition of:

Correct AnswerverifiedShow Answer

Which one of the following improvements could be made to increase the chromatographic (separation) efficiency of a poorly resolved HPLC separation?

Correct AnswerverifiedShow Answer

In the thin layer chromatography procedure for drug screening,the retention factor (Rf) value for a compound is given by the:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedB

Some analytes must be derivatized to increase their column retention or detectability.Derivatization means:

Correct AnswerverifiedShow Answer

In the isolation of nucleic acids from blood samples,a step is typically performed to separate large molecules,such as proteins and nucleic acids,from smaller molecules such as salts.Which type of separation mechanism would best be suited for this task?

Correct AnswerverifiedShow Answer

The type of separation mechanism for chromatography that involves,as one example,use of immunologic principles is _____ chromatography.

Correct AnswerverifiedB

In clinical applications using gas chromatography,which one of the following column temperature techniques will cause the more volatile analytes to elute first and therefore produce the best separation of complex mixtures of analytes with a range of volatilities?

Correct AnswerverifiedShow Answer

In HPLC,analyte detectors can consist of fluorometers,photometers,and electrochemical detectors.An electrochemical detector measures an electroactive analyte by:

Correct AnswerverifiedShow Answer

You are preparing placental tissue for separation and isolation of a specific enzyme.The enzyme has a negative charge,so you want to use chromatography to perform your task.Which one of the following chromatographic separation mechanisms would be most useful?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedA

In column chromatography,analytes are identified by their retention times.

Correct AnswerverifiedShow Answer

A type of detector used in GC that is universal in its detection of compounds but has low sensitivity compared with other detectors is a(n) _____ detector.

Correct AnswerverifiedShow Answer

What component of an HPLC introduces an aliquot of sample into the column and how is this introduction accomplished with the high pressure in the flow path?

Correct AnswerverifiedShow Answer

Thin layer chromatography is a type of planar chromatography with separation based on the principles of partition chromatography.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

In the thin layer chromatography procedure for drug screening,the retention factor (R_f) value for a compound is given by the:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified