[Dolphinsiu]

Leading edge = solute diffuse from mobile phase to stationary phase

But how about _________ edge = solute diffuse from stationary phase to mobile phase? (Since I cannot follow the pronunciation of the lecturer, like ''chasing/tracing'', but I cannot be sure the actual answer in the blank!

[invisiblegs]

So, it seems as though you are saying here that the leading edge, or beginning of a chromatographic peak is determined by the action of diffusion of an analyte from the mobile phase to the stationary phase.  Is this a correct statement of your first answer?  If so, then this may be called retention, and it may be said that the shape/slope of the leading edge of the peak is determined by the homogeneity of this retention process.  Then we need to think about the other parts of the peak, and what may be described by the opposite action, where the analyte diffuses from the stationary phase to the mobile phase (desorption vs adsorption?)  What part of the chromatographic peak will this action control?

[Dolphinsiu]

I have found book that say 'trailing' edge

[chiralic]

Read information on this link:
http://www.lcresources.com/wiki/index.php?title=ChromFAQ:Tailing

Regards,

Chiralic