Chromatographic Methods

Question 1

Technique in which the components of a mixture are separated based on differences in the rates at which they are carried through a stationary phase by a mobile phase

Answer 1

Chromatography

Question 2

Solid or liquid film coated on a solid substrate that is fixed in place wither in a column or on a planar surface

Answer 2

Stationary phase

Question 3

Liquid or gas that moves over or through the stationary phase carrying with it the analyte mixture

Answer 3

Mobile phase

Question 4

Components of a sample are resolved on a packed column by _____, a process in which components are carried througha stationary phase by the movement of a mobile phase.

Answer 4

Elution

Question 5

A plot of the detector’s response as a function of elution time (or volume of mobile phase) is called _____

Answer 5

Chromatogram

Question 6

Time between the sample’s injection and the appearance of a solute peak at the detector of a column

Answer 6

Retention time

Question 7

Width of a solute’s chromatographic peak at the baseline

Answer 7

Baseline width

Question 8

Small peak on the left of a chromatogram is for _______: the time required to elute them is called ____

Answer 8

Dead or void time

Question 9

A quantitative measure of the separation of two chromatographic peaks

Answer 9

Resolution

Question 10

The amount of time a solute spends in the stationary phase relative to the time it spends in the mobile phase

Answer 10

Retention factor

Question 11

The relative selectivity of a chromatographic column for a pair of solutes is given by

Answer 11

Selectivity factor

Question 12

_____ and _____ are widely used as quantitative measures of chromatographic column efficiency.

Answer 12

Plate heights and plate count

Question 13

In a van deemter equation, constants A, B, and C are

A. Longitudinal difussion, Coefficients of multiple path effects, Mass transfer
B. Coefficients of multiple path effects, Longitudinal difussion, Mass transfer
C. Mass transfer, Longitudinal difussion

Answer 13

B

Question 14

Van deemter equation is only applicable for packed columns at _____ flow velocities

Answer 14

High

Question 15

Most common movile ohases for gas chromatography which are chemically inert towards both sample and stationary phase.

Answer 15

He, Ar, N2

Question 16

A chromatographic column
- packed with stationary phase
- short column length with large ID
- large sample
- poor resolution

Answer 16

Open tubular column

Question 17

A chromatographic column
- coated with stationary phase
- long column length with small ID
- small amount of sample
- better resolution

Answer 17

Capillary column

Question 18

5% of the injected sample enters the column

Answer 18

Split injection

Question 19

Over 98% of injected sample enters the column

Answer 19

Splitless injection

Question 20

This part of gas chromatography instrument rapidly volatilizes the components in a liquid sample

Answer 20

Heated injection

Question 21

Temperature control where the column is maintained at constant temperature

Answer 21

Isothermal Programming

Question 22

Refers to the temperature control that sets oven to increase temperature at a specific time interval

Answer 22

Temperature programming

Question 23

Oldest GC detector, universal detector that responds to all substances

Answer 23

TCD Thermal Conductivity

Question 24

Most commonly used general detector used for all organic substances

Answer 24

FID Flame Ionization

Question 25

GC detector that is sensitive for compounds containing electronegative atoms

Answer 25

ECD Electron Capture

Question 26

Non-destructive GC Detector, more sensitive than FID for many compounds such as substituted aromatics and cyclic compounds

Answer 26

PID Photomtric Ionization

Question 27

NPD, a detector for nitrogen- and phosphorus- containing substances is also called _____

Answer 27

Thermionic Specific Detector TSD

Question 28

GC detector used for nearly all substances that can provide structural and molecular weight information

Answer 28

MS Mass Spectrometry

Question 29

Identify if GLC or GSC 1. Liquid S phase 2. Solid S phase 3. Uses packed column 4. Used capillary column 5. Partition principle 6. Adsorption principle 7. Shorter retention time 8. Longer retention time

Answer 29

1. GLC 2. GSC 3. GSC 4. GLC 5. GLC 6. GSC 7. GLC 8. GSC

Question 30

Of all analytical separation techniques, ____ is widely used because of it's sensitivity, adaptability, ease of automation, and widespread applicability to substances that are important to industry.

Answer 30

Liquid Chromatography

Question 31

Aspirates the mobile phase from the solvent resevoir and forces it through the systems column and detector

Answer 31

Pump

Question 32

An elution with a single solvent or solvent mixture of constant composition

Answer 32

Isocratic elution

Question 33

An elution with two (or sometimes more) solvent systems that differ significantly in polarity is used

Answer 33

Gradient elution

Question 34

Automated tools designed to quickly and accurately load samples. It increases the speed and accuracy of sample loading

Answer 34

HPLC Autosamplers

Question 35

An HPLC includes two columns. ____ is responsible for the separation, and _____ protects it from contamination

Answer 35

Analytical column, guard column

Question 36

LC detector that respond to some proerty of solutes, such as UV Vis absorbance, fluorescence, or diffusion current

Answer 36

Solute property detectors

Question 37

LC detector that responds to a mobile ohase bulk property including refractive index, dielectric constant, or density

Answer 37

Bulk-proert detectors

Question 38

Most widely used type of HPLC wherein the S phase is a second liquid that is immiscible with the liquid mobile phase

Answer 38

Partition Chromatography

Question 39

The liquid is held in place by physical adsorption in ____, while it's covalently bonded in _____ chromatography

Answer 39

L-L chromatography, Liquid-bonded-phase

Question 40

Most useful bonded-phase coatings are ____ formed by reaction of hydrolyzed surface with an organochlorosilane

Answer 40

Siloxanes

Question 41

Partition Chromatography with polar S phase and nonpolar M phase.

Answer 41

Normal-phase chromatography

Question 42

Partition Chromatography with nonpolar S phase and polar M phase.

Answer 42

Reversed- phase chromatography

Question 43

Processes based on exchange equilibria between ions in solution and ions in siliar charges on the surface of an insoluble, high MW solid.

Answer 43

Ion-exchange

Question 44

Powerful technique particularly applicable to high molecular weight species

Answer 44

Size-exclusion or gel chromatography

Question 45

Chromatography based on hydrophilic packing

Answer 45

Gel titration

Question 46

Technique based on hydrophobic packings

Answer 46

Gel permeation

Question 47

Involves covalently bonding a reagent, the affinity ligand, to a solid support

Answer 47

Affinity chromatography

Question 48

A hybrid of GC and LC that combines the best features of each. Best method for nonvolatile or thermally unstable species that contain no chromophoric groups

Answer 48

Supercritical fluid chromatography