Can someone help me with calculation with spectrophotometer value?

Question

Determination of copper in a soil solution

From the absorbance value how can I determine the amount of Cu (mg/Kg) in my soil sample. Answer plz very urgent.

Answer 1

Did you run standards at the beginning of the analysis?  If so, make a scatter chart with standards in excel with y= concentration and x= absorption.  Set the intercept at zero (optional) and display equation (y=mx+b) (see below).   Then solve.

sample concentration=m*sample absorbance+b