| The pyrolysis behavior of latent fragrant compound N-(2,3-pyrazinediformyl) alanine methyl ester was investigated by on-line pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS).Firstly,the new compound N-(2,3-pyrazinediformyl) alanine methyl ester was synthesized by amidation using 2,3-pyrazinedicarboxylic acid as material,and its structure was confirmed by X-ray single crystal diffractometry(XRD),1H NMR,13C NMR,IR and HR-MS.In air atmosphere,the compound was pyrolyzed at 300,600 and 900 ℃,respectively.The pyrolysis products were directly introduced into GC-MS to analyse qualitatively and semi-quantitatively.The results indicated that 48 pyrolysis products were detected,including the flavorous substances such as pyrazines,4-methoxy-benzenemethanol and 4-methoxy-benzaldehyde.The pyrolysis temperature affected the pyrolysis pattern and the relative content of the products.The relative content of acetic acid was the highest at 300 ℃ and 600 ℃,and that of pyrazine was the highest at 900 ℃.Compared with that of the pyrolysis at 300 and 600 ℃,the generated pyrazine derivatives sort and the relative content of pyrazine were the highest when pyrolyzing at 900 ℃.On the other hand,in the pyrolysis products with aroma characteristics,the relative contents of 4-methoxy-benzenemethanol increased monotonically with increase of pyrolysis temperature,while the relative content of 4-methoxy-benzaldehyde and benzaldehyde showed a decreasing tendency with a rise of temperature.The possible pyrolysis mechanism of N-(2,3-pyrazinediformyl) alanine methyl ester was preliminarily discussed based on the determined pyrolysates and quantitative changes with the temperature.It is a simple and rapid way to use Py-GC-MS technology in the separation and identification of pyrolysis products. |