82. Solving a chemistry problem

1) A mixture of cations contained in milk, when separated in a thin layer of alumina with acetone containing 8% water and 8% conc HCL, gave after development with K4[Fe(CN)6] 3 spots with an Rf value: 0.27, 0.58 0.70 respectively.
Samples of cations - witnesses, placed on the same plate, have the following Rf values: Ni2 + - 0.26; Co2+- 0.44; Cu2+ - 0.57; Fe3+- 0.69. Determine the cations that make up milk, as well as their normal concentration in the product according to the formula C \u003d KDS, if it is known that K \u003d 0.2; and the spot areas on the chromatogram for Ni2+ , Co2+, Cu2+, Fe3+ are 40mm2 42mm2 50mm2 45mm2, respectively, and their optical densities D: 0.0125, 0.0120, 0.020, 0.0165.