A fully robotic method for the determination of acid values in olive oil without titration

A method for the determination of acid values (AV) in olive oil without titration is proposed, based on pH measurements on an oil sample emulsion in a suitable reagent and fully automated using a robotic station. The robot performs the weighing of the sample, adds the reagent, emulsifies both, and measures the pH of the emulsion. The data are acquired and treated by the computer. After optimization, two versions of the measurement step (interpolation within a calibration curve and addition of standard) are developed and applied to 51 oil samples with AV values that also have been determined by the standard method based on potentiometric titration. Both versions are statistically compared with the standard method, and no significant differences are found. Excellent correlation (R>0.99) between all three methods demonstrates the usefulness of the fully automated approach that works at a sample rate of 15 sample h⁻¹ with relative standard deviations lower than 2.5%.