reading an absorption graph?

Hey again! By absorption chart, do you mean gas chromatography (Spectroscopy)?

Here is a website that tells you how to read a chromatogram:

http://www.ehow.com/how_5459590_read-gas-chromatograph.html

Here is also an example I dug up from my old organic chemistry class:

A gas chromatograph is calibrated for the analysis of isooctane (a major gasoline component) using the following data: %(x) = 0.352, 0.803, 1.08, 1.38, 1.75 and Instrument Response(y) = 1.09, 1.78, 2.60, 3.03, 4.01. If the instrument response is 2.75, what percentage of isooctane is present?

- The best way to do this is to make a calibration curve by plotting Instrument response vs. %. A regression line will give you the relationship between response and percentage. Just plug in 2.75 to the equation and solve for %.

Here is another website: http://www.rpi.edu/dept/chem-eng/Biotech-Environ/CHROMO/chromintro.html

If you need further assistance, reply back.