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Analytical Chemistry > Chromatographic Methods > Flashcards

Chromatographic Methods Flashcards

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1
Q

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

A

Chromatography

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2
Q

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

A

Stationary phase

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3
Q

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

A

Mobile phase

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4
Q

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.

A

Elution

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5
Q

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

A

Chromatogram

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6
Q

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

A

Retention time

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7
Q

Width of a solute’s chromatographic peak at the baseline

A

Baseline width

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8
Q

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

A

Dead or void time

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9
Q

A quantitative measure of the separation of two chromatographic peaks

A

Resolution

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10
Q

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

A

Retention factor

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11
Q

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

A

Selectivity factor

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12
Q

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

A

Plate heights and plate count

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13
Q

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

A

B

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14
Q

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

A

High

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15
Q

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

A

He, Ar, N2

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16
Q

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

A

Open tubular column

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17
Q

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

A

Capillary column

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18
Q

5% of the injected sample enters the column

A

Split injection

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19
Q

Over 98% of injected sample enters the column

A

Splitless injection

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20
Q

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

A

Heated injection

21
Q

Temperature control where the column is maintained at constant temperature

A

Isothermal Programming

22
Q

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

A

Temperature programming

23
Q

Oldest GC detector, universal detector that responds to all substances

A

TCD Thermal Conductivity

24
Q

Most commonly used general detector used for all organic substances

A

FID Flame Ionization

25
Q

GC detector that is sensitive for compounds containing electronegative atoms

A

ECD Electron Capture

26
Q

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

A

PID Photomtric Ionization

27
Q

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

A

Thermionic Specific Detector TSD

28
Q

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

A

MS Mass Spectrometry

29
Q

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

A
  1. GLC
  2. GSC
  3. GSC
  4. GLC
  5. GLC
  6. GSC
  7. GLC
  8. GSC
30
Q

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.

A

Liquid Chromatography

31
Q

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

A

Pump

32
Q

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

A

Isocratic elution

33
Q

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

A

Gradient elution

34
Q

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

A

HPLC Autosamplers

35
Q

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

A

Analytical column, guard column

36
Q

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

A

Solute property detectors

37
Q

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

A

Bulk-proert detectors

38
Q

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

A

Partition Chromatography

39
Q

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

A

L-L chromatography, Liquid-bonded-phase

40
Q

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

A

Siloxanes

41
Q

Partition Chromatography with polar S phase and nonpolar M phase.

A

Normal-phase chromatography

42
Q

Partition Chromatography with nonpolar S phase and polar M phase.

A

Reversed- phase chromatography

43
Q

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

A

Ion-exchange

44
Q

Powerful technique particularly applicable to high molecular weight species

A

Size-exclusion or gel chromatography

45
Q

Chromatography based on hydrophilic packing

A

Gel titration

46
Q

Technique based on hydrophobic packings

A

Gel permeation

47
Q

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

A

Affinity chromatography

48
Q

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

A

Supercritical fluid chromatography

Analytical Chemistry (16 decks)

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