Negative field desorption mass spectra of 30 organic acids (mostly simple sulfonic acids) or their salts has been reported in this paper. Most of the acids studied give rise to the formation of simple negative ions in. [M - M]- or [M - salt option](-) Very low fragmentation or the parent molecules is observed. Addition of additive such as LiCl enhances the intensity of ion signals. Cluster of these molecules are also observed but their intensity is very Low.