PTAG
Shimadzu LC20AT HPLC (Kyoto, Japan) was used to determine PTAG in
oxidized oil following the previously reported method (Hwang, et al.,
2014). Oil sample dissolved in dichloromethane (about 10 mg oil in 10 ml
dichloromethane) was transferred to an autosampler vial, and the
solution (10 µl) was injected into a size exclusion column (PLGel, 5 μm,
300 x 7.5 mm, 100Å pore size, Polymer Labs, Amherst, MA, USA). A Sedex
model 75 evaporative light scattering detector (ELSD) (Sedere, Inc.,
Cranbury, NJ, USA) was used as detector. The operation temperature of
ELSD was 40 ºC, and nebulizer gas was nitrogen (3.5 bar). Percentages of
peaks in chromatograms are reported.