A fast and validated capillary zone electrophoresis method for the determination of selected fatty acids applied to food and cosmetic purposes
Fatty acids (FA) are classically determined by gas chromatographic (GC), but capillary electrophoresis (CE) can be used to determine fingerprint FA in only some minutes, employing small amounts of reagents and solvents, without requiring specific columns to analysis. In this work, palmitic (C16:0), stearic (C18:0), oleic (C18:1 c9) and linoleic FA (C18:2 c9c12) were determined in pumpkin seed oil and a moisturizing cream containing this oil by capillary zone electrophoresis under indirect ultraviolet absorption detection (CZE-UV), showing the potential of CE to FA determination in challenging matrices. The method was validated considering limits of detection and quantification (LOD and LOQ), linearity, accuracy and repeatability. It may be used to a fast monitoring of FA in food and cosmetics, and also for labelling purposes. LOD for C16:0, C18:0, C18:1 c9 and C18:2 c9c12 were 0.03, 0.05, 0.04 and 0.04 mmol L-1, respectively and LOQ was 0.1 mmolL-1 for all FA. No significative difference was found between the classical GC and this alternative method within the 95% confidence interval. Furthermore, the repeatability tests showed slight relative standard deviations considering migration time, evidencing the precision of this CZE-UV method.