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Concentration calculation after HPLC analysis

Posted: Wed May 27, 2020 8:06 am
by sansastark
Hi there,
I will like some help confirming my calculations for the study below:

I have taken a sample with 86% moisture content, weighed out triplicate samples for HPLC analysis which averaged out at 504 mg.
The sample was extracted in 10 mL of solvent and 100uL of this extract was mixed with 900 uL to give a 1 mL sample which was injected into the HPLC.
The concentration after HPLC analysis was 127 mg/L and I have done some calculations where I got 18.2% w/w as the concentration of my analyte of interest. Is this correct?

Thanks a lot in advance

Re: Concentration calculation after HPLC analysis

Posted: Wed May 27, 2020 1:05 pm
by rb6banjo
Z = mg of analyte in the 10 mL extract

I'm assuming 100% of your analyte is extracted in that single, 10 mL shot.

Conc of analyte in the extract is Z/10 mg/mL

Z mg/10 mL x 0.1 mL/1 mL x 1,000 mL/L = 127 mg/L

Z mg = 127 x 10/(0.1 x 1,000) = 12.7 mg in the 10 mL extract

% Analyte in Sample = 12.7/504 x 100 = 2.5%

If you're concerned about the amount of analyte in the non-water matter, there's only 14% . So the non-water matter is 504 x 0.14 = 70.56 mg

%Analyte in the Non-Water Matter = 12.7/70.56 x 100 = 18%

Re: Concentration calculation after HPLC analysis

Posted: Wed May 27, 2020 3:29 pm
by sansastark
Thanks a lot for your help :)

Re: Concentration calculation after HPLC analysis

Posted: Wed May 27, 2020 7:19 pm
by rb6banjo
My pleasure.