With the linearity of the standard curve, NMR spectra of a dimer acid mixture containing CDA were evaluated. The intensity area ratio value of CDA from Fig. 6b was assigned to Fig. 6a and therein the CDA content was estimated via constructed mesitylene mass of standard curve. The estimated contents of CDA by the curve were presented in Table 2. Furthermore, general quantification technique using proton NMR was adopted to show the feasibility of proposed method based on pseudo-standard material. For this purpose, the CDA content (lg/g dimer acids mixture) in each sample was calculated from a previously suggested equation [19–21]: