90. Solving a chemistry problem

9. From a mixture of amines weighing 2.8638 g, triethylamine was quantitatively extracted by extraction with 25 ml of isobutanol (isobutanol density 0.8027 g/cm3). Chromatography of the extract gave a peak of triethylamine 8.5% in isobutanol gave a peak area of 55 mm3. Determine the mass fraction of triethylamine in the mixture if the volumes of standard and test solutions introduced into the chromatograph are the same.