Measuring of concentration by HPLC

[zanio]

Hi all,

I have a guestion about calculation of concentration. of amaunt of X in sample as mg/g.

It was measured on analitical balance sample with m=0,5 000g
Extraction with 15 ml solvent
Then the extract was filtrated in buchner and washed with 1-2 ml H2O.
After that 20 ml solvent was added.
5 ml of solution was taken and evaporated 1 ml.
After that 7 ml of solvend was added and put in HPLC for analysis.
The results from HPLC is 1mg/ ml.
What is the concentration in sample as mg/ g?

What is the formula that I can use?

Thank you!

[dblux_]

Hi all,

I have a guestion about calculation of concentration. of amaunt of X in sample as mg/g.

It was measured on analitical balance sample with m=0,5 000g
Extraction with 15 ml solvent
Then the extract was filtrated in buchner and washed with 1-2 ml H2O.
After that 20 ml solvent was added.
5 ml of solution was taken and evaporated 1 ml.
After that 7 ml of solvend was added and put in HPLC for analysis.
The results from HPLC is 1mg/ ml.
What is the concentration in sample as mg/ g?

What is the formula that I can use?

Thank you!

Between 115,2 and 118,4 mg/g ( ! 1-2 mL of water !)

Was the solvent miscible with water ? No information - I assumed it was.

Never use formulas for concentration calculation. Simply start thinking logically.

[zanio]

Thank you!

Yes the solvent is misible in wather.

How do calculate the concentration?

[dblux_]

Thank you!

Yes the solvent is misible in wather.

How do calculate the concentration?

1. analyte was extracted with 15 mL of solvent and 1 mL of water was added to supernatant then 20 mL of solvent was added
total volume was 15+1+20 = 36 mL
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2. 5 mL was taken, evaporated to 1 mL and diluted to 8 mL and analysed
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3. concentration from HPLC was 1mg/mL so in 8 mL there was 8 mg of analyte
(in fact 8 mg in 5 mL of solution - see point 2.)
---------------
4. 36 mL/ 5 = 7,2

7,2 x 8 mg = 57,6 mg in 0,5 g of sample
so in 1 g there was 115,2 mg of analyte