Dear Dr. Anvari-Yazdi:

Being right that there is not chemical interaction with of the alloy components, the simplest approach to the question would be as follow based only a set of spectroscopics features.

One of chemical route of synthesis of the Formazan (purple) is based on the Tetrazole reducting, as in cells,  which can be solubilized  in DMSO, with characteristic color reached close to purple color, after an optimum solubilization point another phenomena actuate on the light absorption. In this sense, the expected color can be found in the wave band of 500 nm up to 600 nm. Here, if wavelength changes, the color change also. In this sense, a change color is possible. In a dilution procedure, there is no change in wavelength only continuous degree palish color is attained. For the cases where a specific wavelength is fundamental for that analysis can be carried out, perhaps be possible that a surfactant can be added in substitution to DMSO, with further effect on the palish color. The classical surfactant is the sodium dodecyl sulfate.

Best regards

Marcos Nobre

Dear Prof. Nobre.

Really thanks for your precise answer. it was very helpful. I found my problem. Actually, my samples react with phenol red in DMEM media and absorb color to it self and then release it to DMSO and makes error for OD. I have to use DMEM media with out phenol red to achieve good results!

Really thanks again for your help.

Dear Dr. Anvari-Yazdi:

I took note of new finds in your research.

Thank you very much by gentle kind of words. Success in the researchers and long-life for you.

Best regards

Marcos Nobre