Abstract: Using thin-layer chromatography(TLC) and column chromatography(CC),the polar compounds(PC) of hogwash oil were compared with those of edible vegetable oil and refine oil. It was found that the waste hogwash oil and some samples of refine oil have obviously tailing phenomenon on the TLC,but edible vegetable oil and refine oil 4(deordorized oil) do not have,so the CC can be used to separate the tailing compounds of hogwash oil and they can be analyzed with infrared spectroscopy(IR). The results showed that absorption peaks at 1746cm-1of Jinlongyu edible 100% corn oil and refine oil 4 are smoothing and do not break up,but the hogwash oil has small absorption peak at 1746cm-1 and have a big broken peak at 1712 cm-1,belonging to the character of aldehyde and ketone compounds. From 1240 to 1100 cm-1,the hogwash oil has fingerprint break,small absorption and turning to the high repetency. There are more bending vibration frequency and the whole polarity,increases. PC content of hogwash oil is much higher than that of deordorized oil and edible Jinlongyu edible 100% corn oil. The tailing compounds are aldehyde and ketone compounds that edible vegetable oil and deordorized oil do not have.

Key words: hogwash oil, thin-layer chromatography(TLC), column chromatography(CC), infrared spectroscopy(IR)