# How do you get the percentage composition of ibuprofen with respect to C,H,N.O?

In order to get the percentage composition of $\text{ibuprofen}$, we would perform a combustion analysis, and the combustion gases of an accurately weighed mass, carbon dioxide and water, would be shunted to a gas chromatograph for analysis. We would get percentages for carbon, and hydrogen, which added up to LESS than 100%. The balance would be assumed to be oxygen.