Method of determining a future color value or corresponding property and arrangement therefor

A method for producing a protein-containing solution (2) or a product (3) produced therefrom, comprising the steps of:

• (i) cultivating a eukaryotic cell expressing a recombinant protein of interest in cell culture;
• (ii) harvesting the recombinant protein;
• (iii) purifying the recombinant protein;
• and
• (iv) optionally formulating the recombinant protein into a pharmaceutically acceptable formulation suitable for administration;
• and
• (v) obtaining at least one sample comprising the recombinant protein in steps (ii), (iii) and/or (iv);
• wherein the sample is the solution (2) or product (3), and wherein the method further comprises performing a method of determining a future color value (12) or corresponding future property of a protein-containing solution (2) or of a protein-containing product (3) prepared therefrom, comprising:
• exciting the fluorescent radiation (6) of the solution (2) or product (3),
• measuring at least one property, preferably a spectrum (6A) or corresponding feature, of the fluorescent radiation (6), and
• determining the future color value (12) or corresponding future property of the solution (2) or product (3) based on a correlation.