17. Chromatography

Question 1

GC - order of elution and resolution is highly dependent on..?

Answer 1

Stationary phase

Question 2

Elution method where the mobile phase remains constant throughout the experiment

Answer 2

Isocratic elution

Question 3

How is quantitative analysis performed in chromatography?

Answer 3

Measured parameter = peak area

Question 4

Most common form of HPLC used in the clinical lab?

Answer 4

Reversed phase partition HPLC

Question 5

Organic compound typically used in a polar mobile phase?

Answer 5

Acetonitrile

Methanol

Question 6

Normally, the ______ phase is nonpolar, and the ________ phase is polar

Answer 6

Mobile = nonpolar
Stationary = polar

Question 7

HPLC - separation depends on these 2 variables

Answer 7

• Solute solubility in stationary phase

- Nature of mobile phase

Question 8

Separation method of choice for amino acids, proteins, water and fat-soluble vitamins, antibiotics

Answer 8

HPLC

Question 9

What are GC columns made of?

Answer 9

Glass or fused silica tubes

Question 10

In GC, this phase is a liquid immobilised inside the column

Answer 10

stationary phase

Question 11

This method can be used for ~85% of all organic compounds

Answer 11

HPLC

Question 12

GC works for approx ____% of all organics

Answer 12

20%

Question 13

2 benefits of using smaller, microbore columns in HPLC?

Answer 13

• Better resolution of peaks

- Less solvent use

Question 14

A compound that is chemically similar to the analyte, but can be detected separately

Answer 14

Internal standard

Question 15

Elution method where there is a change in acetonitrile (mobile phase) throughout the experiment

Answer 15

Gradient elution

Question 16

2 factors that affect how compounds are separated on a GC column?

Answer 16

• AFFINITY of the solute for the liquid

- VOLATILITY of the solute

Question 17

2 clinical applications of headspace sampling?

Answer 17

• Blood alcohol determination

- Ethylene oxide residue in medical devices

Question 18

Separation method of choice for detecting cocaine, heroin, ethanol, steroids, aromatics?

Answer 18

GC

Question 19

This value helps eliminate possibilities, but cannot give a positive compound ID

Answer 19

Retention time (tr)

Question 20

GC can only be used for __________ and ___________ compounds

Answer 20

volatile

thermally-stable

Question 21

In HPLC, which phase is polar? Nonpolar?

Answer 21

Polar - mobile

Nonpolar - stationary

Question 22

3 main components of a mass spectrometer?

Answer 22

• Ion source
• Mass filter (analyser)
• Detector

Question 23

Multiple __________ are frequently used in order to generate calibration graphs for chromatography quantitative analysis

Answer 23

standards