[adamos1945]

hello
I would like to ask for help regarding calculation of dilution factor to get the amount of mycotoxin per gram of sample. the extraction protocol as fellow:
-ground 5 g of sample with 25 mL of methanol: ACN: water (25:25:50).
-shake for 20 min and centrifuge for 10 min at 2500 xg.
-filter supernatant through filter paper.
-take 10 mL of extract, mix with 40 mL of PBS and filter through microfiber filter.
-pass 10 mL of diluted extract through Vicam column, wash column using 10 mL of PBS, and elute fumonisins by passing 1.5 mL of HPLC grade methanol. collect the elute in vial.
-dry down methanol elute.
-redissolve elute in 400 uL of ACN: water (50:50).
-mix 30 uL of well-mixed redissolved elute with 30 uL OPA reagent.
-inject 30 uL.
we made the standard curve using ppm as unit. so for calculating the concentration , should we use ppm as the standard curve?
how to calculate the dilution factor for this protocol to get amount of mycotoxin per g of sample?
thanks for your help.

[Arkcon]

You can try to work with this problem by reviewing what's been done, and doing the math.  Consider: if you could put a gram of sample into the column, you'd have the answer directly.  If you could put half a gram onto the column, you'd just double the result.  But you can't do that.  But you can figure out how the initial 5 gram sample has been diluted, by all the steps, to get a sample that gave an HPLC response.