111. Solving a chemistry problem

116. For the determination of dioxydiphenylmethane (DDM) in vegetables, thin layer chromatography was used to separate and quantify by spot area S. For standard samples, the following data were obtained:

C(DDM), μg/0.02 cm3 1.25 2.56 6.40 18.2 25.1
S, mm2 9 13 23 58 80

150 g of carrots were treated with 100 cm3 of alcohol, which was then evaporated to 10 cm3. Chromatography of 0.02 cm3 of this solution gave a spot with an area of 35 mm2. Determine the content of dioxydiphenylmethane in carrots (mg/kg).