Screening the volatiles isolated from a standard polypropylene material consisting of a polypropylene homopolymer, the filler talcum, and a mixture of antioxidants, for odor-active compounds by application of an aroma extract dilution analysis revealed 30 odorants with flavor dilution factors ranging from 1 to 64. Eighteen odor-active compounds were subsequently quantitated by gas chromatography-mass spectrometry using stable isotopically substituted odorants as internal standards, and their odor activity values (OAVs) were calculated as ratios of the concentrations to the odor threshold values. Five odorants showed OAVs ≥1, among which were hex-1-en-3-one (OAV 12), butanoic acid (OAV 3), as well as 4-methylphenol, butan-1-ol, and 2-tert-butylphenol (all OAV 1). A comparative analysis of polypropylene materials with different additives suggested plastic-like, pungent smelling hex-1-en-3-one as an ubiquitous key odorant. Odor-active amounts of alkylphenols, in particular plastic-like, phenolic smelling 2-tert-butylphenol, were additionally formed in the presence of talcum and phenolic antioxidants. Whereas the precursors of the phenols were thus obvious, the origin of hex-1-en-3-one was unknown. Injection molding showed only little influence on odorant concentrations.

中文翻译：

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聚丙烯材料不良气味的分子背景和对关键气味剂来源的洞察

通过应用香气提取物稀释分析，筛选从由聚丙烯均聚物、填料滑石和抗氧化剂混合物组成的标准聚丙烯材料中分离出的挥发性物质中的气味活性化合物，发现有 30 种气味剂，其风味稀释因子范围为 1 到 64 . 十八种气味活性化合物随后通过气相色谱-质谱法使用稳定同位素取代的气味剂作为内标进行定量，并且它们的气味活性值 (OAV) 被计算为浓度与气味阈值的比率。五种气味剂显示 OAV ≥1，其中 hex-1-en-3-one (OAV 12)、丁酸 (OAV 3) 以及 4-甲基苯酚、butan-1-ol 和 2- tert-丁基苯酚（所有 OAV 1）。对具有不同添加剂的聚丙烯材料进行的比较分析表明，类似塑料、具有刺激性气味的 hex-1-en-3-one 是一种无处不在的关键气味剂。在滑石和酚类抗氧化剂的存在下，额外形成气味活性量的烷基酚，特别是类似塑料的、有酚气味的2-叔丁基苯酚。尽管酚类的前体是显而易见的，但 hex-1-en-3-one 的来源却是未知的。注塑成型对气味浓度的影响很小。