Plate model of chromatography

causes of diffusion
> eddy diffusion: each molecule takes a different path down the column varying in length. independent of speed of mobile phase.
> molecular diffusion: solute goes from area of high conc to low conc. broadening increases with time. inversely proportional to velocity of mobile phase.
> resistance to mass transfer: something someething newtons 3rd law. broadening increases with velocity of mobile phase
Definitions
> chromatatogram: plot of solute concentration vs time
> retention time: time solute is withheld by the column.
> Resolution: a measure of a columns ability to separate solutes with similar mobilities.
Gas chromatography
> dependent of volatility of substance
> heat that shit up and things travel thru the column at diff times due to the differences in volatility

> EI (bombard w electrons and fragments) (small molecule only)
> CI (no clue) (small molecule only, difficult to predict)
> MALDI (laser go pew pew) (good for large molecules, minimal fragmentation, must be non volatile)
> ESI (charge with electricity and it explodes or smthign) (sample needs to be polar and soluble) (use when lots of h-bnd and ionic)