Hello, according to this formula the result is really 30%, you are right:

Va% = the volatile parte of the sample.

if your sample has 10 g and after evaporation it result of 7 g of non volatile matter, then you have 3 g of volatile material, that is 30% of the sample.

Dear Dr. Wan Mohamad Ikhmal,

I think you followed the ASTM D2369 01 procedure, regarding the "Volatile contents of Coatings".

The percent of volatile matter, V in liquid samples is calculated as follows:

% V = 100 - [(W2-Wi / S) x100]

where: W1 = weight of Al dish

W2 = weight of dish plus specimen after heat to 110 ° C for 60 min.

S = specimen weight

Then: % VOC =% V -% sample water content.

All weights are espressed in g.

I hope I have been helpful to you ...

Best regards, Pierluigi Traverso

Thank you very much dear Dr. Pierluigi Traverso and Dr. SILAS DERENZO . I've been very confused previously due to the presence of factorial (!) in the equation. But, now I understand the way to do it. :D