General

Question 0

May be hyphenated and linked to MS as a….

Answer 0

Detection method

Question 1

Five key elements in a chromatography machine….

Answer 1

Stationary phase
Mobile phase
Mechanism to make components move in MP. 
A way to add the sample.
A detection method.

Question 2

What is chromatography?

Answer 2

A separation technique for compounds so that they can be quantified and identified. Eg blood.

Question 3

What is the stationary phase?

Answer 3

A material that interacts with the compound depending on its physical or chemical properties.

Question 4

What is the mobile phase?

Answer 4

The phase that compounds are dissolved into. This passes over the SP.

Question 5

Polar compounds…… Water

Answer 5

Love

Question 6

Non polar…….. Water.

Answer 6

Hate

Question 7

What is analytical chromatography?

Answer 7

Separation quantitively, to determine how much of a substance there is, and qualitatively, to separate individual compounds for identification.

Question 8

There is no alteration of……

Answer 8

Compounds.

Question 9

What is preparative chromatography?

Answer 9

A complex mixture can be separated and purified to give a purer compound with fewer or no contaminants.

Question 10

What is preparative chromatography used for?

Answer 10

Prep of samples of pure proteins, such as blood.

Question 11

What is paper chromatography?

Answer 11

Process carried out on a piece of absorbent paper - The SP.

Question 12

Why is chromatography used?

Answer 12

Most analytical methods are specific for a compound or class of compounds so therefore require the sample to be separated into constituent parts before analysis.

Question 13

How does the retention time affect the peak shape?

Answer 13

The peak will be broader with an increasing retention time.

Question 14

The retention time is calculated using the…

Answer 14

Centre of the peak.

Question 15

The retention time of a compound is….

Answer 15

The time is takes for each compound to move through the column.

Question 16

A compound that doesn’t interact with the SP will have…

Answer 16

The same retention time as the mobile phase.

Question 17

The output on a detector is the….

Answer 17

Signal intensity over the time of elution.

Question 18

The peak resolution (Rs) is the….

Answer 18

Ability of a chromatography process to separate two solutes in a sample.

Question 19

The equation for peak resolution (Rs) is….

Answer 19

Rs = t R2 - t R1 / 1/2 (Wb1 + Wb2)

Where R1 is first to elute.

Question 20

Peak resolution values are acceptable around….

Answer 20

1.0

Question 21

A longer retention time and smaller peak width = a….

Answer 21

Better resolution and high Rs value.

Question 22

Retention time may vary as…

Answer 22

Some compounds will be retained on the column for longer.

Question 23

Column efficiency is….

Answer 23

How good a column is at separating solutes.

Question 24

Theoretical plates (N) can be used in the column, the more plates =

Answer 24

More steps = greater efficiency to separate columns in a reasonable time.

Question 25

A smaller plate height =

Answer 25

Greater efficiency by having a shorter column length.

Question 26

The van Deemter equation states that….

Answer 26

Plate height will increase and efficiency will therefore decrease, as the values of the constants A B C increase.

Question 27

C constant is most dominant in LC because of….

Answer 27

Slow diffusion in liquid MP.

Question 28

C constant has less impact in….

Answer 28

GC.