Artículos de revistas
Increasing titration speed by using an end paint anticipator device
Quimica Analitica. Elsevier Informacion Professional, S A, v. 20, n. 1, n. 55, n. 58, 2001.
A simple device is described for use in any titrations with the objective of rapidly locating the vicinity of the end point of a titration. The device stores inside about 10% of a 10 mL titrand solution. The titration itself proceeds with rapid addition of titrant until the end point is passed. The anticipator device now starts to rotate, using a dc motor, which is turned on by a micro-computer. The solution stored in the device is mixed with the already titrated solution and the property being monitored returns to a reading before the end point. The titration is now continued, knowing that the volume (or mass) necessary to reach the true end point is about 10% greater than the value found in the pre-titration. The computer estimates this volume and controls the last part of the titration, calculating the volume/mass increments. This considerably speeds up the titration process and obtains the necessary number of points for a precise and accurate localisation of the end point using the titration curve. The device has been evaluated in potentiometric titration of HCl and of acetic acid with NaOH as titrant, and using a gravimetric burette. The results demonstrate that a titration can be performed in about 1.5 minutes by using the anticipator device, with no significant difference when compared with the conventional, stepwise and slower titrant addition procedure.2015558