[Eknerlmsjds]

I have a quick question that I couldn't find else where on the web or this site. This also might just be a very simple question and that I am over thinking it way too much, for this I am sorry.

I injected 20 microliters of a sample of tea, that I prepared, into the HPLC for analysis, the loop was only 20 microliters. The tea sample was initially prepared by various means of extraction which left me with a dry product, and to prepare for HPLC analysis brought up in 10.00 ml of Methanol. I made a calibration curve of what I was trying to find (an antioxidant EGCG) in my sample, plotted all the results from the standards, and performed a regression analysis which I used to find the concentration of EGCG in my sample.

My question is, to find the mass of EGCG from in my original sample would I just do

(Concentration)(10.00)(0.020 ml) = mass in micrograms of EGCG

or

(Concentration)(10.00 ml) = mass in micrograms of EGCG ?


TLdr: Is loop volume necessary to calculate in when the injection concentration of an unknown is determined through a calibration curve?

[JGK]

What concentration units have you used for the calibration.

If the units are µg/mL then the loop volume is unnecessary.

Take get the µg/mL value for your unknown, multiply by 10 to get total µg in the sample and the divige by the sample wt (g) to get a µg/g value for the tea.