Investigation of Pyrolysis Behavior of Lutein in Air by Thermogravimetry-Single Drop Microextraction-Gas Chromatography-Mass Spectrometry

To investigate the pyrolysis behavior of lutein in air, an automatic single drop microextraction (SDME) device for trapping the released fractions was designed and coupled with gas chromatography-mass spectrometry. According to the results of differential thermal-thermo gravimetric analysis (TG-DTA), the pyrolysis process was divided into 16 temperature sections in the range of 155-400℃, and the released fractions at each section were sampled successively. The extract effect of SDME with ethanol as a solvent was analyzed by comparing the mass loss in each temperature section with the total peak area of pyrolysis products. The probable mechanism of lutein pyrolysis in air was inferred on the basis of dynamically monitoring the changes of relative contents of 43 main pyrolysis components. The results indicated that: 1) The optimized conditions for the thermoanalyzer were: temperature ascending rate 5℃/minute and carrier gas flow rate 400 mL/minute. 2) SDME performed excellently in the extraction of volatile components in pyrolysis products. 3) The main components identified by GC/MS included ketones, aldehydes, alcohols, alkenes and aromatic hydrocarbons, the most important pyrolysis products were β-damascenone, megastigmatrienone and 4-oxoisophorone.