Method for detecting concentration of mixed acid solution

The invention provides a method for detecting the concentration of a mixed acid solution. In the prior art, the concentrations of various acids in a mixed acid to be detected cannot be accurately measured, or a detection process is complicated, the consumed time is long and more materials are used. The method for detecting the concentration of the mixed acid solution comprises the following steps: providing the mixed acid to be detected with a pre-set volume and a pH compound electrode; titrating with alkali liquid and detecting to obtain a first equivalent point and a second equivalent point by the pH compound electrode; determining the concentration of total hydrogen ions and the concentration of fluosilicic acid in the mixed acid through the first equivalent point and the second equivalent point; carrying out acid titration to recover the pH value of the mixed acid to be neutral; then adding lanthanum nitrate to titrate and detecting by the pH compound electrode to obtain a third equivalent point; and dete