The determination of the acid or base number plays a significant part in the analysis of petroleum products. This is shown by the numerous worldwide standard procedures (internal specifications of multinational companies, national and international specifications of ASTM, DIN, IP, ISO, etc.). These procedures differ mainly in the composition of the solvents and titrants used. Fortunately, the days of the work-intensive use of pH meters, glass burets, and color indicators seem to be over. Modern titrators are gradually replacing time-consuming manual titrations as well as the calculation of the results.
This Bulletin describes the determination of the acid and base number in petroleum products by automatic potentiometric titration.