Ch 34 Miscellaneous Separation Method

Question 1

The physical state of a substance held/ heated above its critical temperature

Answer 1

Supercritical fluid

Question 2

Is the temperature above which a substance cannot be liquified

Answer 2

Critical temperature

Question 2

Acts as the mobile phase in supercritical fluid chromatography and are able to dissolve large nonvolatile molecules

Answer 2

Supercritical fluid

Question 3

The density of a supercritical fluid is ___ to ____ times that of its gaseous state

Answer 3

200 to 400

Question 3

The pumping system in SFC that keeps the fluid in liquid state

Answer 3

Chilled pump head

Question 4

The effects of pressure to the density of the supercritical fluids

Answer 4

Directly proportional

Question 5

The most widely used mobile phase for supercritical fluid chromatography

Answer 5

CO2

Question 6

Give the planar chromatographic techniques

Answer 6

Thin-layer Chrom
Paper Chrom
Electrochrom

Question 6

Named the different detectors than can be used in SFC

Answer 6

Flame ionization detector
UV-visible absorption detectors
Light scattering detectors
Mass Spectrometry (Hyphenation)
Tandem mass spec

Question 7

Can be considered a form of liquid-solid chrom in which the stationary phase is a thin layer on the surface of a plate. The mobile phase is drawn by capillary action

Answer 7

Thin-layer chrom

Question 7

This is a chromatographic technique where the mobile phase moves through the stationary phase by capillary action, sometimes assisted by gravity or an electrical potential

Answer 7

Planar chrom

Question 8

Commercial plates used in TLC that have thicker layers of 200 to 250 μm, particle size of >20 μm

Answer 8

Conventional plates

Question 8

Commercial plates used in TLC that have thicker layers of 100 μm, particle size of <5 μm

Answer 8

High-performance plates

Question 9

The most critical aspect of TLC where the sample is applied as a spot 1 to 2 cm from the edge of the plate

Answer 9

Sample application

Question 9

Increases the precision and accuracy of sample application

Answer 9

Mechanical dispenser

Question 10

The process by which a sample is carried through the stationary phase by a mobile phase. Analogous to elution in liquid chromatography

Answer 10

Plate development

Question 11

The process of locating analytes on a thin-layer plate is often termed as

Answer 11

Visualization

Question 11

Two common methods in locating the analytes on the plate

Answer 11

1. Spraying iodine or sulfuric acid solution
2. Incorporation of fluorescent material to the stationary phase

Question 12

Samples are placed on both ends of the plate and developed towards the middle, thus doubling the number of samples

Answer 12

Horizontal-flow developing chamber

Question 13

Two types of developing chamber

Answer 13

Ascending-flow
Horizontal-flow

Question 13

Separation of analytes that uses a stationary phase from a highly purified cellulose with close control over porosity or thickness

Answer 13

Paper chrom

Question 13

The separation method based on the differential rates of migration of charged species in an applied electric field

Answer 13

Electrophoresis

Question 14

Have a unique ability to separate charged molecules of interest

Answer 14

Electrophoresis

Question 15

An electrophoresis that is carried out in columns and separate micro amounts of sample in fused-silica capillary tubes

Answer 15

Capillary Electrophoresis

Question 16

Enumerate the steps on the instrumentation of TLC

Answer 16

Preparation of TLC plates Sample Application Plate development Locating analytes on the plate

Question 17

Dictate the instrumentation of Capillary electrophoresis

Answer 17

- Fuse-silica capillaries have two buffer reservoirs that hold platinum electrodes. - The sample is introduced at one end and detection at the other end. - Sample introduction is through electrokinetic or pressure injection - Voltage is applied causing ionic migration and electroosmotic flow - Detected

Question 18

The flow of the solvent as it migrates towards the cathode as the voltage is applied

Answer 18

Electroosmotic flow

Question 19

A record or chart produced when electrophoresis is used in an analytical technique,

Answer 19

Electropherogram

Question 20

The ratio of the migration rate of an ion to the applied electric field

Answer 20

Electrophoretic mobility

Question 21

Formula for the migration rate of ion in an electric field

Answer 21

v = μc x E v = μc x V/L

Question 22

Capillary electrophoretic separations are performed in several ways called

Answer 22

modes

Question 23

types of modes in electrophoresis

Answer 23

Isoelectric focusing, isotachophoresis, capillary zone electrophoresis

Question 24

Is a hybrid of HPLC and capillary electrophoresis. It is capable to separate neutral species and provides highly efficient separation on microvolumes of sample

Answer 24

Capillary electrochromatography

Question 25

This is the level where the surfactant begins to form spherical aggregates made up to 40 to 100 ions with their hydrocarbon tails and their charged ends exposed to water in the outside

Answer 25

Critical Micelle Concentration

Question 25

This form in aqueous solution when the concentration of an ionic species having a long-chain hydrocarbon tail is increased above a certain level

Answer 25

Micelles

Question 26

The least mature of the various electroseparation techniques. A polar solvent is usually driven by electroosmotic flow through a capillary that is packed with a reversed-phase HPLC packing.

Answer 26

Packed Column Electrochromatography

Question 27

Capillary electrophoresis carried out in the presence of micelles is termed

Answer 27

Micellar electrokinetic capillary chromatography (MECC)

Question 28

The technique where surfactants are added to the operating buffer in amounts that exceeded the critical micelle concentration

Answer 28

Micellar electrokinetic capillary chromatography (MECC)

Question 29

Common surfactant used in MECC

Answer 29

SDS or Sodium Dodecyl Sulfate

Question 30

A moving phase that acts as a stationary phase (e.g., the micelles in MEKC)

Answer 30

Pseodustationary phase

Question 31

A group of analytical techniques that separate and characterized dissolved or suspended materials such as polymers and colloids

Answer 31

Field-flow Fractionation (FFF)

Question 32

In FFF, the sample components migrate towards the ________

Answer 32

Accumulation wall

Question 33

The separation results in FFF that reveal the plot of detector response vs time is called

Answer 33

Fractogram

Question 34

What are the FFF methods

Answer 34

Sedimentation FFF, electrical FFF, thermal FFF, and flow FFF

Question 35

An FFF technique where the channel is coiled and made to fit inside a centrifuge basket wherein components that have higher mass and density are elute last and low-mass species are eluted first

Answer 35

Sedimentation FFF

Question 36

An FFF technique where an electric field is applied perpendicular to the flow direction and thus, separates based on electrical charge. Species with higher charge are driven effectively towards the accumulation wall (retained the most), whereas lower charge species are eluted first

Answer 36

Electrical FFF

Question 37

An FFF technique where a thermal field is applied perpendicular to the flow direction by forming a temperature gradient across the channel

Answer 37

Thermal FFF

Question 38

The most versatile of all FFF techniques where the external field is replaced by a slow cross flow of the carrier liquid

Answer 38

Flow FFF