Analysis of Main Odor Substances in Recycled Polyethylene by HS£­SPME/GC£­MS with Relative Odor Activity Value

KeyWord:recycled polyethylene  headspace solid phase microextraction/gas chromatography£­mass spectrometry  main odor substances  relative odor activity value

Abstract:

      In order to investigate the volatile odor components of recycled polyethylene£¨PE£© and their contribution to the overall odor of recycled PE£¬the volatile odor compounds in 8 kinds of recycled PE were analyzed by headspace solid phase microextraction/gas chromatography£­mass spectrometry£¨HS£­SPME/GC£­MS£© coupled with retention indexs£¨RI£©£®The main odor substances were evaluated by relative odor activity value£¨ROAV£©£®The extraction temperature was 80 ¡æ£¬the equilibrium time was 30 min£¬the extraction time was 40 min£¬the extraction fiber was 50/30 ¦Ìm DVB/CAR/PDMS and the chromatographic column was HP£­5 MS£¨30 m ¡Á 0.25 mm£¬0.25 ¦Ìm£©£®Results showed that 47 odor substances in 8 kinds of recycled PE were detected£¬including 14 esters£¬11 alcohols£¬6 ketones£¬4 aldehydes£¬4 phenols£¬2 alkanes£¬2 olefins£¬2 ethers£¬1 carboxylic acid and 1 amine£®Among the obtained odor compounds£¬there were 31 kinds of common ingredients. The ROAV showed that nonanal£¬isophorone£¬amyl salicylate£¬diphenyl ether£¬2-methoxynaphthalene£¬phenol and borneol were the main odor substances in eight kinds of recycled PE. The odor of recycled PE was one of the important factors limiting its application£®This research could provide a theoretical basis for the improvement of degassing and deodorization process of recycled PE£®