High Performance Liquid Chromatography Flashcards
What was high-performance liquid chromatography developed from?
Gas chromatography
What is done to the substance being analysed during HPLC
The substance being analysed is added to a liquid solvent (mobile phase)
What is the mobile phase in HPLC?
A liquid solvent
What is done to the liquid phase in HPLC?
It is passed over very fine silica particles (stationary phase)
What acts as the stationary phase in HPLC?
Very fine silica particles
Why are very fine silica particles used as the stationary phase?
It was discovered that better separation of the components of the mixture occurs if the particles in the stationary phase are very small
What is the issue with using very fine particles in the column during HPLC?
The liquid passes very slowly through the column
The liquid passes very slowly through the column during HPLC, what is done to combat this?
A pump is used to force the liquid through the column
What is the solvent reservoir?
This is a large bottle of the liquid solvent used which is drawn out using a pump
What is chromatography in which a pump is used to force a liquid through a tightly packed column called?
High-performance liquid chromatography
What is high-performance liquid chromatography?
Chromatography in which a pump is used to force a liquid through a tightly packed column
What is the principle of high-performance liquid chromatography?
A liquid mobile phase is in contact with a stationary phase (fine particles of a solid) and separation of the mixture occurs as a result of selective adsorbance of the components of the mixture on the stationary phase
What are the five processes involved in the use of the HPLC instrument?
(5)
Injection of sample containing the mixture
Pumping if sample along the column
Separation in the column
Detection of components of mixture
Display of results
Why does the column not need to be as long in HPLC than in GC?
Since separation is more efficient in HPLC
What is the column made of in HPLC?
Stainless steel
Why does the column need to be made from stainless steel?
To withstand the high pressure of HPLC
What are the advantages of HPLC over GC?
2
It is carried out at a lower temperature than GC so it can be used to analyse compounds that would decompose at the high temperature needed for GC
It is particularly suited to analysis of mixtures of compounds that are non-volatile and this unable to be separated by gas chromatography
What is HPLC commonly used in?
5
To test for the presence of growth promoters in meat
To test for vitamins in food
To test for additives in food
To measure the concentration of alcohol in blood
To measure the concentration of caffeine I’m drinks
What may HPLC be used in conjunction with?
Mass spectrometry
Why may mass spectrometry be used in conjunction with HPLC?
To aid the identification of compounds
