Short chain fatty acids analysis by capillary electrophoresis and indirect UV detection or laser-induced fluorescence

Short chain fatty acids are difficult to study using conventional techniques such as gas chromatography, because of their high volatility. Capillary electrophoresis (CE) and UV detection or conductimetry was used to study fatty acids of 6 carbon lengths or less. Difficulties in dissolving longer acids in aqueous buffer prevented analysis by CE. Recently indirect laser-induced fluorescence was used to study C-6 to C-18 fatty acids and the sensitivity of the detection was in the sub-micromolar range. In this paper we studied C-5 to C-18 branched, hydroxy or linear fatty acids using CE and UV indirect detection and we succeeded in obtaining good separations but with very poor sensitivity (limited to 10(-5) M). In a second attempt we studied fatty acids after 5-bromomethylfluorescein derivation and analysis by CE and laser-induced fluorescence (LIF). The sensitivity was in the sub-nanomolar (10(-10) M) range but we could only study C-8 to C-11 fatty acids. Using CE-LIF, we quantitated these acids in normal and pathological serae. (C) 1997 Elsevier Science B.V.