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<正>在中国人的传统里,一年中最重要的一顿饭当数大年三十晚上这顿年夜饭。年夜饭的概念对不同时代的人群有着不同的回忆和理解。不同的时代,我们的年,也有着不同的过法。眨眼间,虎年春节又来 相似文献
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Xichao Chen Qian Luo Shengguang Yuan Zi Wei Hanwen Song Donghong Wang Zijian Wang 《环境科学学报(英文版)》2013,25(11):2313-2323
Taste and odor (T&O) problems in drinking water frequently occur because of many compounds present in the water, of which trans-1,10-dimethyl-trans-9-decalol (geosrnin) and 2-methylisoborneol (MIB) are well-known. In this study, a fast and effective method was established for simultaneous determination of 10 T&O compounds, including geosmin, MIB, 2,4,6-trichloroanisole (TCA), 2-methylbenzofuran, 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), cis-3-hexenyl acetate, trans,trans-2,4-heptadienal, trans, cis-2,6-nonadienal, and trans-2-decenal in water samples by headspace solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. An orthogonal array experimental design was used to optimize the effects of SPME fiber, extraction temperature, stirring rate, NaC1 content, extraction time, and desorption time. The limits of detection ranged from 0.1 to 73 ng/L were lower than or close to the odor threshold concentrations (OTCs). All the 10 T&O compounds were detected in the 14 water samples including surface water, treatment process water and tap water, taken from a waterworks in Lianyungang City, China. MIB and geosmin were detected in most samples at low concentration. Six T&O compounds (IPMP, IBMP, trans,cis-2,6-nonadienal, 2-methylbenzofuran, trans-2-decenal, and TCA) were effectively decreased in water treatment process (sedimentation and filtration) that is different from cis-3-hexenyl acetate, MIB and geosmin. It is noted that the TCA concentrations at 15.9-122.3 ng/L and the trans,cis-2,6-nonadienal concentrations at 79.9-190.1 ng/L were over 10 times higher than their OTCs in tap water. The variation of the analytes in the all water samples, especially distribution system indicated that distribution system cannot be ignored as a T&O compounds source. 相似文献
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鱼的味道鲜美、营养丰富,是人们餐桌不可或缺的美食.但你知道吗?为了健康着想,吃鱼的时候要慎重,有些会对人体造成损害的鱼类是千万吃不得的. 相似文献
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