Introduction to Chromatography

Question 1

Chromatography is derived from the Greek words..?

Answer 1

Chroma which means color and graphy which means writing

Question 2

Chromatography is a technique for separating mixtures into their components to _____, _____, _____, and _____ the mixtures or components

Answer 2

analyze, identify, purify, quantify

Question 3

It is based on a forced transport of _____(_____ phase) carrying the analyte mixture through the porous media and differences in the _____/_____ at analytes with the surface of this porous media resulting in different migration times for a mixture of compounds.

Answer 3

liquid(mobile, interactions/affinities

Question 4

What is the mobile phase? Provide an example.

Answer 4

The mobile phase provides the analyte transport. For example, water adsorbed on the filter paper (paper chrom), and silica (TLC)

Question 5

Briefly discuss the stationary phase.

Answer 5

It is the immobile phase. It is pure solvent/solvent mixture. An example is hexane-chloroform

Question 6

There are 4 major uses of chromatography. Namely, analyze, identify, purify, and quantify. Briefly discuss all 4.

Answer 6

Analyze: examine a mixture and its components
Identify: determination of identity of mixture or component based on standards
purify: to separate components to isolate & separate compounds
quantify: to determine amount of mixture/components in a sample

Question 7

In column chromatography, where is the stationary phase located? The sample? The mobile phase?

Answer 7

inside a column/tube (silica packed in the column). Sample is placed on top. Mobile Phase is ran through the column

Question 8

Determine whether what state/d of matter does the following chromatographic techniques utilize.
Gas Chromatography

Answer 8

Mobile Phase: Gas
Stationary Phase: Either solid or liquid

Question 9

Supercritical chromatography’s mobile phase utilizes what?

Answer 9

Supercritical fluid e.g. carbon dioxide

Question 10

Liquid chromatography, as its name suggests, utilizes liquid in its mobile phase. It is also used in different separation methods. What are these?

Answer 10

Normal Phase LC (NPLC), Reversed Phase LC (RPLC), Ion Exchange (IEX), and Size Exclusion Chrom (SEC)

Question 11

TF: In NPLC, the SP is polar while the MP is nonpolar?

Answer 11

True

Question 12

TF: In RPLC, the SP is polar, and the MP is nonpolar.

Answer 12

False. It is the other way around.

Question 13

In ion exchange (IEX), the SP are resins which can be either _____ or _____?

Answer 13

cation exchanger: (-) charge
anion exchanger: (+) charge

The MP also contains ions

Question 14

Explain how the SEC works.

Answer 14

1. Separation is based on mechanical entrapment or size ONLY
2. works as a molecular sieve
3. SP has a cutoff (does not account for ones bigger than pores)

The bigger the molecule, the faster is the elution

Question 15

what is the main feature of Planar Chromatography?

Answer 15

Its stationary phase is flat

Question 16

What is Capillary Electrochromatography?

Answer 16

It is a hybrid technique that combines principles of chromatography and electrophoresis

Question 17

Give at least 3 advantages of HPLC over classical chromatography.

Answer 17

1. high speed
2. high resolution
3. high sensitivity
4. reusable column
5. no destruction of the components/sample
6. instrumentation are automatic, computerized
7. samples is recovered completely
8. quantitative work is done more easily and more sensitive