[socomplicated]

hi guys!

i wonder where in a peak i can predict the concentration of my compound in a HPLC chromatogram? in GC chromatogram it is the ratio area under the peak, but how about  in HPLC? is that the ratio HEIGHT or ratio AREA of the peak that tells us about its concentration?

thank you all alot!  

[kevins]

You can use Peak height or Peak area to calculate the concentration and the results are no big different. My experience is to see which one is sharp on the chromatogram. E.g. if a very sharp peak was found then I will use the peak height, if a flat peak then I will use the peak area for calculation. This is an ideal case because of the stupid computer program can't let you do it separately.

[angiems]

kevin seems to have it down, although I've only ever seen anyone calculate concentration based on peak area (not that I have all that much experience...)

[Mitch]

I suspect peak area is the most reliable.

[socomplicated]

thanks all!  

[jdurg]

I would agree with the peak area as well, since that should take care of any 'oddities' in the elution time of the compound.  The concentration will be determined by the entire area of the peak no matter how long it takes to come off the column.  With peak height, the same concentration can wind up looking completey different if the elution times are slightly extended.  (I.E. in run one the peak height is higher, but the peak is narrower, while in run two the peak height is VERY slightly smaller and the peak is VERY slightly wider.  Trying to decide if you should use the height and not the area is a bit to subjective.  Area will always exist and will not be subjective.)