I'm currently working on an electrolytic setting where a stainless steel (430 series, mainly made of iron and chromium, but no nickel) anode is dissolved in acidic environment (sulfuric and phosphoric acids at moderate concentrations).
My concern is the hypothetical creation of dichromate ions, since they are carcinogenic. But I can't confirm only color-wise because of the presence of other ions that mixes all the colors.
The experiment runs for long (3 hours). At first an orange color appears, which suggests dichromate ions (but could be Fe III). But after only a little while, the solution turns to a very dark and deep green, almost blue depending on the light. This suggests chromium III ions.
Several things could be happening, such as reduction of Cr VI to Cr III at the cathode, or just creation at the anode of Cr III whose color overwhelms that of Cr VI, or even Fe II or Fe III messing with the color.
Does anyone have an idea about a means to confirm or infirm the presence of dichromate ions despite not being able to judge by the color ? And if so, how could I determine the concentration of it ?
Thanks a lot in advance.