Silver ion solid-phase extraction cartridges employing glass housings overcome the limitations observed in the GC analysis of animal lipids with low trans fatty acid content

Custom made silver ion solid-phase extraction (Ag+-SPE) cartridges with glass housing were evaluated to see whether they could be used to analyze the trans fatty acids (TFA) in animal products when present at low concentration. Previous attempts were not successful to identify and characterize the TFA using commercial Ag+-SPE cartridges, because of the coelution of artifacts from these cartridges. The glass cartridges proved successful to identify the low levels of TFA present in horse and wild boar meat. It is recommended that the supplier make available Ag+-SPE cartridges in glass housing to avoid the problem of interferences. Practical applications: It was previously shown that commercially available silver ion solid-phase extraction (Ag+-SPE) cartridges could not be used to analyze biological samples with low levels of TFAs, because of interfering contaminants that eluted from the polypropylene housing. Custom made glass cartridges were generously provided by the supplier, and they proved successful to fractionate the geometric isomers of horse and wild boar lipids both of which are known to contain low levels of TFAs. Subsequent gas chromatographic analysis made it possible to identify the trans and cis isomers without interference of contaminants. The unsaturated fatty acid fractions from these glass cartridges were also free of contaminants. Ag+-SPE cartridges in glass housing are recommended to resolve and identify the trans isomers when present at low concentrations in biological samples.