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Flashcards in HPLC Deck (19)
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1

3 types of liquid chromatography methods:

paper chromatography
thin layer chromatography
liquid column chromatography

2

Differences in preparative vs analytical LC?

Analytical:
- goal is to identify/quantify target molecules
- small volume/column size/particle size
- high pressure (HPLC or UHPLC)

Preparative:
- goal is to purify/collect (clear interferences)
- large volume/column/particle size
- low pressure

3

What is the usual column/particle size and sample volumne for analytical LC?

Sample: 0.01 - several microL

column: mm

particle size: um

4

what is the goal for preparative LC?

Purify/collect large quantity of molecule of interest (get rid of interferences)

5

What is the usual column/particle size and sample volume for prep LC?

Volume: mL - L
column: 5-10cm
particle: >10um

6

What is the pressure range for low pressure LC, HPLC, and UHPLC?

low pressure: <10 bars
HPLC: >50 bars
UHPLC: >600 bars

7

the pressure reading is 450 bars. This is considered ____ LC.

HPLC

8

the main parts of a HPLC system: (7)

Solvent(s)
Pump(s)
Mixer
Injector (autosampler)
Column
Detector
Waste

9

What is the stationary phase in HPLC? What is the mobile phase?

stationary: column (packing material)
Mobile: solvent(s)

10

What is responsible for maintaining the pressure and flow in the HPLC system?

pump

11

Describe the path of the solvent through the system:

bottles -> tubing -> pump -> mixer -> (sample injected) -> column -> detector -> waste

12

Types of LC columns: (6)

reverse phase
normal phase
ion exchange
size-exclusion
affinity
chiral

13

What is reverse phase LC? give an example of a column and mobile phase.

nonpolar stationary phase + polar mobile phase

column: C18
solvent: aqueous (water/acetone/methanol)

14

What is normal phase LC? give an example of a column and mobile phase.

polar stationary phase + nonpolar mobile phase

column: silica
solvent: organic (hexane)

15

Advantage/disadvantage of smaller particle size in HPLC:

good: small particle -> small theoretical plate height (H); broader range of optimal flow rates

bad: higher back pressure

16

parts of an LC pump: (6)

vacuum chamber
proportioning valve
inlet valve
outlet valve
damper
purge valve

17

the y axis and x axis of a chromatogram:

y axis = detector signal
x axis = time

18

parameters of a chromatographic peak:

peak height
peak width
peak area

19

What is 2D-LC?

coupling 2 LC columns with different separating powers
(further separate individual peaks - display results as 2D chromatogram)