Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HPLC > HPLC > Flashcards

HPLC Flashcards

1
Q

Hvad står HPLC for?

A

High Performance Liquid Chromatography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hvilke to metoder findes til injection?

A

Manuel/automatisk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Hvad er fordelen ved højere temp?

A

Hurtigere runs, større detectability og nogle stoffer bliver bedre opløst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Hvad sker der i den kolonnen/ stationære fase?

A

Seperationen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Hvad er pumpens funktion?

A

skaber højt tryk i den mobile fase og samplen (højt tryk - konstant flow)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Detektoren måler..?

A

Retentionstiden

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

I reversed phase HPLC er den mobile fase…?

A

Polært solvent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Hvad består den stationære fase af i reverse fase?

A

nonpolære eller lipofile perler

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hvordan filtreres prøven inden HPLC’en?

A

gennem et 0,5 um filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Hvad skal laves på forhånd for at bestemme koncentrationer?

A

Standard kurve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Arealet under kurven er propertionalt med…?

A

Koncentrationen af stoffet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Hvilken matematisk analysemetode anvendes til at bestemme koncentrationerne af stoffet?

A

Lineær regression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Lipofile molekyler tiltrækkes af hinanden. Hvad hedder kraften der tiltrækker nonpolære stoffer (lipofile) til hinanden?

A

London dispersion krafter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Hvad kaldes tiden som samplen residuerer i den stationære fase relativt til dens tid i den mobile fase?

A

Retentionsfaktoren

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hvordan kan man sikre sig en god sample seperation? (efter samplen er forberedt korrekt)

A

Der anvendes en kolonne og en mobil fase med forskellig polaritet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hvordan ser et godt peak ud?

A

Det er symmetrisk og perfekt separeret

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Hvis der ikke sker separation, hvordan ser peaket ud så?

A

kun 1 stort peak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hvis en prøve har været opbevaret under ekstreme forhold, og der derefter kommer mindre peaks, hvad betyder det så?

A

lavere koncentrationer

19
Q

Perlerne i kolonnen kaldes for…?

A

Den stationære fase

20
Q

Hvad er nogle af de mest brugte mobile faser i reverse phase?

A

Methanol og acetonitril

21
Q

Hvordan laves en standard/kalibreringskurve?

A

Kendte koncentrationer køres gennem systemet og der laves lineær regression på peaks

22
Q

hvordan er stationær og mobil fase i reversed-fase?

A

hydrofobisk stationær; polær mobil

23
Q

forholdet mellem hvor lang tid det tager en prøve at passere gennem den stationære fase sammenlignet med hvor lang tid det tager at passere gennem søjlen med den mobile fases hastighed kaldes ?

A

Retentionsfaktoren (k)

24
Q

i reverse-fase HPLC injiceres en prøve indeholdende 2 forbindelser. Forbindelse A er mere lipofil end forbindelse B. hvilken forbindelse vil eluere først fra kolonnen?

A

B

25
Q

Hvad kaldes ratioen af retentionsfaktorer af peaks?

A

selektivitet

26
Q

Kolonne effektiviteten kan måles ved at beregne teoretisk ‘plate’ nummer ved at sammenholde …. og …

A

retentionstid ; bredde ved baseline

27
Q

det teoretiske ‘plate’ nummer kan øges ved at..?

A

Gøre størrelsen af perlerne i den stationære fase mindre

28
Q

Når der anvendes mindre perler i den stationære fase, medfører det… ?

A

højere tryk

29
Q

Fortæl om normal fase hplc

A

Uses non polar MP like he ans
uses polar SP - silica bonded with polar functional group like Cyano
useful for separation of polar compounds as Sp is polar
Polar compounds retained longer on SP and higher retention times
eluent strength (how quickly it elites) is increased by adding more polar solvent. More polar MP = Higher éludent strength of MP = faster solute elute from column as polar solute will attract to it
most non polar elute first as polar react with SP

30
Q

Fortæl om reversed phase hplc

A

Use polar MP (methanol/water) and non-polar SP(C18)
use to seperate non-polar compounds ans more non polar will elute last a
éludent strength is increased by adding less polar solvent
popular as peaks tend to be narrow and symmetrical
mist polar solutes elute first as non polar react with SP

31
Q

Basale komponenter i instrumentet

A

-Solvent delivery system (a pump)
-sample injection valve
-pre column or guard column
-high pressure column
detector
-computer

32
Q

Fordele v. HPLC

A
  • Wider range of possible mobile phase properties
  • wider choice of SP and detectors than GC
  • suitable for non - volatile components
  • useful for analytes that decompose at high temps
33
Q

Typer af detektorer i HPLC

A
  • spectrophotonetric - UVVIS
  • electrichemical - mesures current due to oxidation of solute
  • others - refractive index detector or LS-Ms (more difficult than GC-MS)
34
Q

Faktorer der påvirker separationen

A
  • Adjust the retention factor (interaction between the solute and SP/MP) by changing solvent strength or no. plates
  • adjust the selectivity by changing temp and MP/SP composition
35
Q

Solvent krav for HPLC

A

Rene; uden partikler; ikke for viskøs

36
Q

Beskriv den analytiske kolonne

A

Packed with SP

normally made if stainless steel

5-30cm length

1-5mm diameter

25,000- 100,000 N

heating column - reduces retention time, improves resolution, degraded SP

narrow columns are preferred as require less sample & generate less waste

37
Q

Isokratisk vs gradient elution?

A

Iso occultes when the elution is performed with a single solvent or solvent mixture at a time. Run at a solvent composition of 100% methanol and then 90%

gradient involves changing the solvent composition during the elution process. Start with 20% methanol ans than gradually change to 80% in 15 minutes. Useful to seperate solutes with widely differing polarities as it ensures they can all be examined in one run and sharpens peak

if différent polarities ans retention times, use gradient

38
Q

Sample introduktion/indførelse

A

Samples are dissolved in MP and passed through a filter to remove impurities before injection

Injection is via a port that has an injection valve and sample loop to waste or column

in modern HPLC, sample injection is automated - precise and accurate sampling

39
Q

Pre-kolonne eller ‘guarding column’?

A

Protects analytical column

has same packing material as analytical column

40
Q

Optimering af resolution?

A

For ions, adjust ph of MP

for others, adjust MP polarity. Changing from a more polar to a less polar decreases retention time in Reversed phase ans changing from less polar to more polar decreases retention time in normal

41
Q

Ion-Exchange Chromatografi (IEC eller IC)

A

Baseret på udveksling af ioniske analytter med mod-ioner af de ioniske grupper der er attached til SP

42
Q

Size exclusion chromatography (SEC)

A

separationsmetode kun baseret på analyttens molekylære størrelse

43
Q

Forklar tailing

A

Stofferne kommer ikke ud samtidigt, så peaket bliver bredere

HPLC (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions