Abstract
An intelligent potentiometric titrator is described which can carry out automatic precipitation titrations under optimum conditions and minimum time. The buret tip is not immersed in the titrand solution as is usually the case, but is held above the solution so as to prevent the titrant from leaking and reacting with the titrand solution during waiting intervals. The titrant is added drop by drop with a motor-driven buret. After each drop of titrant has been added, the buret is stopped and values of the potential difference obtained with predetermined short time intervals (e.g. 1s) are stored in a microcomputer. From the convergence of several successive values, the microcomputer determines whether there has been a substantial attainment of the precipitation equilibrium, stores the final value in the memory and sends a control signal to the buret to resume titrant addition. These operations are repeated until the equivalence point is passed. The exact equivalence point could be evaluated by any common method. Particularly, Gran′s plot method is preferred. The appropriateness of the system, including hardware and software, has been demonstrated by titration of silver ions with chloride, which gave very reasonable results.
