What is mass spectroscopy?
an analytical technique used to indentify unknown compounds
What can the mass spectroscopy be used to find?
the relative abundance of the isotopes experimentally
what is the [m+1] peak caused by?
the presence of the carbon 13 isotope in the molecule
what is the [m+2] peak caused by?
(and possibly the [m+4] peak
the presence of bromine or chlorine
e.g. the 35cl+35cl gives?
which combination of which chlorine isotopes gives rise to which peaks?
35 + 35 = M+ peak
35 + 37 = [M+2] peak
37 + 37 = [M+4] peak
the ratio for the peaks are 9:6:1
which combination of which bromine isotopes gives rise to which peaks?
79 + 79= M+ peak
79+ 81= [M+2] peak
81 + 81= [M+4] peak
the ratio for the peaks are 1:2:1
What is thin-layer chromatography?
a technique used to analyse small samples via separation
what is the stationary phase of thin layer chromatography?
commonly it is aluminium oxide or silic (SiO2)
How does the stationary phase in thin-layer chromatography work?
the solute molecules adsorb onto the surface and depending on the strength of interactions with the SP the separated components will travel a certain distances. the more they interact the more they will stick to it
What is the mobile phase of the thin-layer chromatography?
a polar or non-polar solvent
What does a higher Rf value indicate about the component in TLC?
the compound is less polar as and can be easily carried up the plate by the solvent and the interaction with the SP is weaker and there is a higher solubility in the mobile phase
what is gas/liquid chromatography used for?
to separate and identify very small samples of gases, liquids and volatile solids
What is the stationary phase of GLC?
gas/liquid chroma
a non polar hydrocarbon with a high boiling point which is mounted onto a solid support
What is the mobile phase of GLC?
an unreactive gas
What is meant by the retention time in GLC?
the time taken for a component to travel through the column
How do you calculate the area under the peak in GLC?
1/2 x base x height
how does the polarity of the molecules relate to the retention time?
a non-polar molecule takes longer to through the column compared to a polar component which prefers to interact with the carrier pas
