Quantification of phenolic antioxidants in rat cerebrospinal fluid by GC–MS after oral administration of compounds

A gas chromatographic-mass spectrometric (GC–MS) method for qualitative and subsequent quantitative analysis of phenolic antioxidants compounds, presents in olive oil, in rat cerebrospinal fluid (CSF) after oral administration of compounds is proposed. The procedure involves the extraction of compounds from the samples by a traditional microliquid–liquid extraction method, followed by a silylation step before the GC–MS analysis. The chromatographic separation was performed by using a low bleed DB5-MS fused-silica capillary column. The presence of 21 phenolic compounds was tested in CSF extracts and only free tyrosol, hydroxytyrosol and ferulic acid were detected. Those compounds were then quantitatively determined using the proposed methology. The molecular ion for silylated compounds appears at 370 m/z for hydroxytyrosol, 282 m/z for tyrosol and 338 m/z for ferulic acid respectively, while the base peak appears at 267 m/z, 179 m/z and 338 m/z. α-Naphthol was used as a surrogate (216 and 201 m/z). The detection capabilities obtained were 74, 92 and 79 ng/mL respectively. The method was applied to the determination of trace amounts of compounds in rat cerebrospinal fluid after oral administration. The animals were fed with a standard chow diet (free of phenolic antioxidants) in order to avoid the influence of any other component of the diet on the CSF of the animals.