Short-chain fatty acids are mainly produced by food and beverage industries during fermentation processes. For example, volatile acidity, which gives bad taste to wine, may appear during the vinification process, especially during storage. This is due to alcohol oxidation by lactic or acetic bacteria [1,2]. The volatile acids formed are acetic, propionic, butyric and valeric acids [1,2]. These fatty acids are malodorous at relatively low contents in ambiant air, i.e. the perception levels of acetic, propionic, butyric and valeric acids are respectively 2, 0.109, 0.014 and 0.020 mg.m -3 [3]. Consequently, these compounds may contribute greatly to the unpleasant odor generated by distilleries where byproducts of the wine industry are used as raw materials.In order to reduce the olfactory pollution in such activities, the compounds responsible for the malodorous emissions must be monitored. Therefore, 4 fatty acids (acetic, propionic, butyric and valeric acids) were chosen as odor markers and analysed in liquid effluents of the main steps of the process. According to the numerous analysis expected, a simple, cheap and fast method was requested. The analytical techniques generally used for the determination of carboxylic acids involve gas chromatography [4,5]. However, the polar acids are not suitable for direct GC injection. Therefore, a preliminary derivatization step is needed, using, for example, esterification by pentafluorobenzyl bromide (PFBBr) or methylation catalyzed by trifluoroboron (BF 3 ) [5,6]. These reactions are performed in organic media and thus require preliminary solvent or solid-phase extractions [7]. These procedures are long and complex to carry out. A more simple and specific approach may consist in performing a separation by ionic chromatography [8]. In this case direct injections of aqueous samples are allowed, but a possible damage of the column can occur after numerous analysis of complex matrices such as distillery effluents. Indeed, this kind of samples are constituted of a wide diversity of organic compounds such as alcohols, carbohydrates, ketones, aldehydes, esters and acids. Thus, capillary zone electrophoresis appears as an interesting alternative method. As example, Roldan-Assad et al. developed the separation of linear saturated fatty acids in their free form from C2 to C14 in less than 10 min [9]. The solubility of the most apolar compounds in the water-based electrolyte was improved by adding cyclodextrins and methanol. An indirect UV detection led to minimum detectable concentrations of the order of 0.2 -0.5 mg.L -1 . Another study also showed good performances of CZE for the analysis of organic acids in biological matrices with limited sample preparation [10].According to these encouraging results, this paper described the development of a CZE method for the fast analysis of short-chain fatty acids in distillery effluents. The performances were defined according to different experimental conditions in order to improve the sensitivity. The possibility of analysing gaseous samp...