Construção e aplicação de eletrodo de aço inoxidável UNS S31254 como eletrodo indicador em titulações condutimétricas

UNS S31254 SS electrodes have been built to substitute platinum in conductimetric titrations. The electrodes were tested in both acid-basic titration (chloridric acid and sodium hydroxide) and precipitation titration (sodium chloride and argentum nitrate as titrant). The practical application was exemplified from conductimetric tritations of HF <FONT FACE=Symbol>¾</FONT> HNO3 mixtures used in metalurgical industry to passivate stainless steels. The results were compared with those obtained using commercial platinum electrodes. The equivalent volumes obtained were comparable within 3% experimental error. Its application depends on the nature of electrolyte. These results have shown that stainless steel, less expensive than platinum (about three order of magnitude), can substitute platinum electrodes in routine analyses and didactic laboratories.