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HPLC709 Mar 11th 2017 03:32 AM

Internal standard calculations..
 
I would like to confirm the volume of internal standard (theophylline) and 5 standard solutions (caffeine) I have calculated to analyze caffeine levels in unknown samples...

Final total volume = 10ml
Stock concentration(caffeine) = 0.4% ; Stock concentration (thophylline) = 0.4%

Standard #1: 0.005% caffeine + 0.03% theophylline
Standard #2: 0.01% caffeine + 0.03% theophylline
Standard #3: 0.015% caffeine + 0.03% theophylline
Standard #4: 0.02% caffeine + 0.03% theophylline
Standard #5: 0.025% caffeine + 0.03% theophylline

My calculations are..

Standard#1 = 0.125ml caffeine (C) + 0.75ml theophylline (T)
Standard#2 = 0.25ml caffeine (C) + 0.75ml T
Standard#3 = 0.375 caffeine (C) + 0.75ml T
Standard#4 = 0.5ml caffeine (C) + 0.75ml T
Standard#5 = 0.625ml caffeine (C) + 0.75ml T

Thank you.


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