Derivatization of NL, PL, and FFA
The NL and PL fractions were dissolved in 2.0 mL of hexane,
then 1.5 mL of 3.33 mg/mL sodium methanolate solution was
added. The samples were placed horizontally on a shaker platform
for 30 min set to 350 motions per min. After 10 min, allowing
phase separation, the hexane layer with fatty acid methyl esters
(FAME) was collected and dried under a stream of nitrogen at
37 °C. The NL and PL fractions were dissolved in 1.0 mL and
200 μL of hexane respectively, and were by this stage ready for
analysis by gas chromatography with a flame ionization detector
(GC-FID).
The FFA fractions were dissolved in 1.0 mL of 14 % BF3 in
methanol. The sampleswere placed in boilingwater for 1 min. The
FAME were extracted with 1.5 mL of hexane, and dried under
a stream of nitrogen at 37 °C. The FFA fractions were dissolved
in 1.0 mL of hexane, and were by this stage ready for GC–FID
analysis. The FFA fraction will not be discussed in detail here. The
data are however available from the corresponding author.