[mahrap]

When I try calibrating my HPLC the areas of the curves of the different concentrations go down as the concentration goes up. What do you think is the cause of this problem? I know more concentrated solutions should give a bigger area but I get the exact opposite pattern.

[Arkcon]

Well, try graphing the data by hand and look at what the curve shows.  Its possible that, instead of "going down", it may be leveling off, because the system is saturating at the higher end.  But that's just an example, we would need to see the data.  And its easier for us if you chart it.

[pottesjaak on den hoak]

perhaps there is a way around it,

I don't know what software your system runs on,

But whenever I encounter callibration problems i tend to cheat and outsmart the system,
if there is a mode in your software, you could manually integrate your peaks let it calculate the area for you,
and by writing down that very area, you can establish a series of different areas of different concentrations.
which you can fill down in you callibration table

that is only if the software supports manual integration ( and other ways of data analysis )

[Archer]

But whenever I encounter callibration problems i tend to cheat and outsmart the system

I take it your lab isn't accredited, if I discovered my staff doing this they would be given a verbal warning, second time would be written and third would be dismissal.

@Mahrap

This is the worst advice anyone can give you! If you have to 'fiddle' your calibration data how do you know whether or not to 'fiddle' your sample(s) which you are trying to quantify? Or will you just change it to suit the answer you were hoping for?

Let's see your data as Arkon suggests and see where we go from there.

Are you using an internal standard?