VOLUMETRIC CONTROL OF AN ELECTROLYTIC ENGRAVING PROCESS - ANALYSIS OFMIXTURES OF HYDROCHLORIC-ACID, PHOSPHORIC-ACID AND ALUMINUM

The volumetric determination of hydrochloric acid, phosphoric acid and free aluminium in electrolytic engraving bath samples is described, T hree consecutive acid-base volumetric measurements were performed, usi ng a commercial combined pH sensor to determine the equivalence volume s of each titration, Sodium fluoride was used to mask the interference of free aluminium in the quantification process for both acids, optim izing the amount of masking agent necessary for quantitative results, The results, evaluated through the preparation of synthetic samples, s how good reproducibility (RSD 1%), The relative error associated with the method was less than 3%. The method presented here facilitates the analytical control of the electrochemical engraving bath in the manuf acture of offset printing matrices, verifying its function and allowin g the optimization and control of the production process.