Separation methods Flashcards
What is the polarity of a compound?
The tendency to act like a magnet with a positive and negatives end. Uneven charge distribution
What is the stationary and mobile phase in gas-liquid chromatography?
Stationary phase is a thin hollow tube coated with a very viscous liquid and the mobile phase is an unreactive gas which carries the components under analysis
What is the purpose of pyrolysis-gas chromatography and how does it work?
Analysis of polymers through heating them without the presence of oxygen to produce pyrolysates, stable fragments. The formation of the pyrolysates is consistent and is used to detect accelerant residue, hairs and fibres
In high performance liquid chromatography which phase is more polar?
Stationary phase is more polar than the mobile phase, although this is reversed in reverse phase chromatography
What is the difference between isocratic and gradient chromatography?
Isocratic chromatography is where the polarity of the mobile phase remains the same during the run while the polarity is altered during gradient chromatography
What can high performance liquid chromatography be used to detect?
Organic substances in soil, explosives, inks and dyes
What is the stationary and mobile phase in thin layer chromatography?
Stationary phase is a thin layer of solid material on a glass or plastic plate and the mobile phase is an organic liquid or water
What are the two types of electrophoresis? What is the purpose of the two?
Gel and capillary. Gel electrophoresis is only used to detect DNA while capillary electrophoresis is used to detect DNA, drugs, explosive and gunshot residue and ink
What principle is involved in electrophoresis?
The stationary phase has one positive end and one negative end and the analyte components move towards the charge opposite their own
What is the difference between the mobile and stationary phases of gel and capillary electrophoresis?
Mobile phase for both is an electric current. Gel stationary phase is a gel material immersed in a buffer to maintain pH. Capillary stationary phase is a thin column
