SPME-GC-MS快速分析炼油厂废水中痕量VOCs

采用固相微萃取-气相色谱-质谱联用(SPME-GC-MS)对炼油厂废水中痕量挥发性有机化合物(VOCs)进行了定性分析,简化了预处理过程,总分析时间为1h左右.对比处理前后的废水样品的MS定性结果,为废水处理工艺的评价以及有机物降解机理提供了依据.     

海南主要地域生咖啡豆挥发性化学成分对比研究

采用固相微萃取-气相色谱-质谱法(SPME-GC-MS)分析海南万宁地区咖啡豆和澄迈地区咖啡豆中挥发性化学组分,通过谱库检索、保留指数对化合物定性,比较两种咖啡豆之间差异。实验结果表明：万宁地区咖啡检出化合物种类91种,澄迈地区咖啡检出106种化合物,有66种相同的化合物,相同组分为75.52%。相同化合物中万宁地区咖啡占总含量的89.86%,澄迈地区咖啡占总含量的85.70%。     

Characterization of the Aroma Profile and Main Key Odorants of Espresso Coffee

Espresso coffee (EC) is a common coffee preparation technique that nowadays is broadly widespread all over the globe. Its popularity is in part attributed to the intense aroma and pleasant flavor. Many researchers have studied and reviewed the aroma of the coffee, but there is a lack of specific review focused on EC aroma profile even if it is intensively investigated. Thus, the objective of the current review was to summarize the aroma profile of EC and how different preparation variables can affect EC flavor. Moreover, a collection of diverse analytical procedures for volatile analysis was also reported. The findings of this survey showed that the volatile fraction of EC is extremely complex, but just some compounds are responsible for the characteristic aroma of the coffee, such as some aldehyde, ketones, furanones, furans, sulfur compounds, pyrazines, etc. In addition, during preparation, some variables, e.g., temperature and pressure of water, granulometry of the coffee particle, and brew ratio, can also modify the aroma profile of this beverage, and therefore its quality. A better understanding of the aroma fraction of EC and how the preparation variables should be adjusted according to desired EC would assist coffee workers in obtaining a higher quality product.     

Screening of antioxidant activity and volatile compounds composition of Chamerion angustifolium (L.) Holub ecotypes grown in Lithuania

Since biological activity of medicinal plants is dependent on cultivation area, climatic conditions, developmental stage, genetic modifications and other factors, it is important to study flora present in different growing sites and geographical zones. This study was focused on screening of antioxidant activity of C. angustifolium harvested in six different locations in Lithuania. The total contents of phenolic compounds, flavonoids and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were evaluated by spectrophotometric methods. A correlation between radical scavenging activity and total phenolic compounds content was observed (correlation coefficient 0.98). HPLC with online post-column DPPH radical scavenging reaction detection was used for the separation of extracts. Oenothein B, rutin and one unidentified compound were predominant. Volatile compounds were analysed using solid-phase microextraction coupled with gas chromatography–mass spectrometry. Based on the analysis of volatiles, all samples were classified into two chemotypes: (I) with predominant α- and β-caryophyllenes and (II) with predominant anethole.     

SPME-GC-MS快速分析炼油厂废水中痕量VOCs

采用固相微萃取 -气相色谱 -质谱联用 (SPME- GC- MS)对炼油厂废水中痕量挥发性有机化合物(VOCs)进行了定性分析 ,简化了预处理过程 ,总分析时间为 1h左右。对比处理前后的废水样品的 MS定性结果 ,为废水处理工艺的评价以及有机物降解机理提供了依据。     

HS-SPME-GC-MS analysis of antioxidant degradation products migrating to drinking water from PE materials and PEX pipes

Polyethylene (PE) and cross-linked polyethylene (PEX) pipes are frequently used in water supply systems. Such pipes contain added antioxidants with phenolic structures, e.g. Irgafos 168, Irganox 1010 and 1076, in order to improve durability. However, phenol, ketone and quinone antioxidant degradation products may leach and enter drinking water. The aim of this investigation was to develop a method for measuring these degradation products with a performance meeting the drinking water quality criteria of 20?µg?L^?1. Using headspace solid phase microextraction coupled to a gas chromatograph with a mass spectrometer, a method was established revealing limits of detection and quantification less than 0.4 and 1?µg?L^?1 respectively. The method was applied to migration experiments for two PEX pipes and one PE material, quantifying the release of two degradation products. Highest concentrations were observed for 2,6-di-tert-butyl-p-benzoquinone which in one of the two pipes was found in concentrations of 18–57?µg?L^?1 in each of eight consecutive release experiments.     

有毒猪油中有机锡的GC-MS测定

用固相微萃取法富集猪油中挥发性杂质, 经色谱分离, 质谱测定, 确定了杂质的成分, 发现有毒猪油中存在６ 种与有机锡化合物有关的杂质, 它们是合成有机锡的原料和副产物,依据这些杂质推断其合成路线, 最终确定有机锡化合物为二硫代醋酸异辛酯二丁基锡。 该法准确, 简便。