[seamoro]

Hello...ive been trying to determine for 3 days now a unknown. I have a calibration curve run on hplc with the following peak areas:
Conc (mg/L)        Peak Area
0                            0
0.001                         43162
0.01                       1027039
0.05                       4623058
0.1                       8742401

The unknown concentration peak area is 1227456 so i should be able to put this in the equation of the line and be able to detemine the concentration!!...but i keep getting strange answers! 1227456-61347/9e+07=118.15. my equation of the line is
y= 9E+07x + 61347
i should be able to put the unknown into this equation and get a concentration like approx 0.012 but instead i get a strange answer 118.15....please help....i know its something simple im doing wrong

[Arkcon]

I get similar values for the equation of the line in my spreadsheet.  Can you graph your data in your spreadsheet?  Plot just your points, draw a line with your formula, and lay them on top of each other?  You should see a good fit given the r-squared value.  Can you look at your unknown area on that line an see the approximate conc. you should get?  These are all things that you can do, to see where you might be going wrong.

[JGK]

Tghe reason you are getting 118.15 is that you are using the antilog function (e^x) when entering 9E+07. You should be using the EXP function on your calculator.


using  1227456-61347/9e+07 (or 9 x 10⁷), I get 0.012956 on my trusty casio