Fully automated photometric titration procedure employing a multicommuted flow analysis setup for acidity determination in fruit juice, vinegar, and wine

Abstract

This work deals with a fully automated multicommuted flow analysis setup employing a homemade syringe pump for fluid propulsion and solenoid valves for solution handling, assembled to carry out photometric titrations using a homemade LED-based photometer. The data acquisition and control software was designed to perform titrations following the binary search concept, in which the course of titration is decided based on previous measurements. The operation conditions were optimized and the setup efficiency was then evaluated by analyzing samples of fruit juice, vinegar, and wine. Furthermore, in order to assess the accuracy, the samples were also analyzed using an independent method. Upon applying the paired t-test to the results, no significant differences at the 95% confidence level were observed. Other useful features are also reported, such as intraday precision of 1.2%, relative standard deviation of 0.9% for an acetic acid solution with a concentration of 0.106molL−1, and a titration range of 0.036 to 0.176molL−1.