1 Reply Latest reply on Jul 24, 2018 12:34 AM by mr.white

    Calculation of Amount, ISTD

    mr.white

      Hello,

       

      I have a Question concerning the Calculation from Chemstation.

       

      We have a run of a trace analysis of a solvent.

       

      Our calibration table got 2 components.

      Solvent 1 amount 79. mg/L   Area 210

      Solvent 2 amount 1.0 mg/L  Area 397  ISTD

       

      Std Run       Run1                                                                                                           Run2  

      Solvent 1 amount 79.0 mg/L Area 213  amount area 3,7 e-1  amt Area Ratio 146.2     Area 210  amt area 3,75 e-1 amt Area Ratio 149.2

      Solvent 2 amount 1.0 mg/L Area 394     amount area 2,5 e-3 amt Area Ratio 1.0         Area 397  amt area 2,51 e-3 amt Area Ratio  1.0

       

      SST Run

      Solvent 1 amount 31,85 mg/L Area 149  

      Solvent 2 amount 1.0 mg/L Area 398    

       

      So the result is 31,85 mg/L ( The Results are from the Chemstation )

       

      We want to reproduce the result on the Open Labs 2.1

       

      Solvent 1 amount 79,0 mg/L Area 290,7

      Solvent 2 amount 1.0 mg/L  Area 532,421              

      Calculation of the calculation factor is Area Solvent 2 divide Area Solvent 1. Which is here 1,8 and above 1.9 so the relativity is the same

       

       

      So we take this factor multiply it by 50 then 2 then 0.79.

      This value we take to calculate  its around 145 = F

       

      The calculation after is Solven1 amount =( ( area solvent 1/ area solvent 2 ) * F * 50 * 2 ) / 10000

      No matter what I do I just don't get the 32 mg.. I assume that there is some Factor that the Chemstation calculates the result with.

       

      So the 2 main questions are.

       

      Is there a chance to review the calculation from the chemstation which is bound in the method ?

      2nd how the Chemstation calculate the Value of 32 mg/L ?

       

      If you need more Details let me know.