BINARY SEARCH IN FLOW TITRATION EMPLOYING PHOTOMETRIC END-POINT DETECTION

A binary search strategy is proposed and implemented in a continuous f low system to find the end-point titration by employing spectrophotome tric detection. It takes advantage of the binary sampling process unde r a constant flow-rate. For this task an automated flow set-up based o n solenoid valves was designed. A 386 microcomputer was employed to co ntrol the valves, and to perform data acquisition and data processing. The accuracy level can be previously settled as a software parameter. Samples with concentrations ranging within two orders of magnitude co uld be titrated by making use of the same flow set-up. Titration of hy drochloric acid with sodium hydroxide was performed to demonstrate the feasibility of the proposal. Titrations in triplicate, with 99.99% pr ecision were carried out in 3 min with a solution consumption of 2 ml.