3.3. 13C Nuclear Magnetic Resonance Spectroscopy (13C NMR) Analysis

The samples were made up to a total volume of 0.6 ml with deuterio chloroform containing ca.25 mM tris(acetylacetonate) chromium (III) as a relaxation agent. Quantitative ¹³C NMR spectra were acquired on a Bruker BioSpin Av500 NMR spectrometer equipped with a 5-mm ¹H-¹³C-¹⁵N inverse triple resonance probe with z gradient operating at 125.8 MHz for ¹³C. The samples were maintained at 25 °C during acquisition. A total of 128 k data points were collected over a spectral width of 26.3 kHz summed over 12–64 k scans.

Inverse gated, bilevel ¹H decoupling was employed with an acquisition time of 2.49 s and a recycle delay of 2.5 s. The data were processed in Bruker BioSpin TopSpin v3.1 over 128 k data points using a Gaussian multiplication with a Gaussian position factor of 0.12 and a line broadening of 0.15 Hz; a 5th order polynomial baseline correction was applied to each spectrum. Spectra were referenced to the peak arising from C₁ of 22:6ω3 in the sn-2 position of triacylglycerols at 172.13 ppm [28] and the signals were assigned using the published assignments of Aursand et al. [29]. Each of the raw data were processed in a similar fashion in triplicate and the average and standard deviations calculated.