[mha695]

What is the other alternative acid to study redox behavior of quartz crystal gold working electrode in acidic solution?

My professor and I were using sulfuric acid and perchloric acid with 0.2M concentration to study the quartz crystal by EQCM technique, but we could not see any changes in mass when we increased or decreased the concentration. The mass changes data did not show any relations to the concentration changes. We were thinking about the other acids such as perbromic acid or periodic acid.