A sensitive and efficient method for the determination of acidity constants of salicylaldoxime (SALO) (2-hydroxybenzaldehyde oxime), using both Raman spectroscopic and potentiometric methods, at 30 °C in 50% (wt/wt) of ethanol–water mixture and at the constant ionic strength I = 0.1 M is proposed. The effect of pH on the Raman spectra has also been studied. The Raman spectroscopic technique allows the identification of compounds in different molecular and molecular ionic structures. The limit of detection (LOD) was determined to be 0.05 mol dm−3 for SALO by means of Raman peak area. Copyright © 2010 John Wiley & Sons, Ltd.