A study of high-boiling alkylbenzene fractions as synthetic lubricants for refrigerators

The properties of synthetic oils based on high-boiling alkylbenzenes - good low temperature behaviour, thermo-oxidative, anticorrosive and hydrolylic stability, make them suitable candidates as lubricating oils for refrigerator machinery. This paper reports the results of investigations by column adrorption chromatography and GC-MS into the nature and properties of three high boiling alkylbenzene fractions, and their behaviour when compounded into candidate refrigerator oils.     

水蒸气蒸馏罗汉松精油工艺及有效成份分析

以杭州市区生长的罗汉松为原料,采用氯化钠盐析辅助水蒸气蒸馏方法对其精油进行提取,通过正交试验考察了影响精油提取率的三因素依次是超声频率、超声时间、氯化钠溶液的浓度,说明罗汉松植物组织的破碎是提高精油收率的重要因素。采用气质联用仪对精油成份进行了分析,得到24种主要化合物,与其它类的松柏精油化合物组成不尽相同。     

Discrimination between defective and non-defective Brazilian coffee beans by their volatile profile

The coffee roasted in Brazil is considered to be of low quality, due to the presence of defective coffee beans that depreciate the beverage quality. In view of the fact that coffee flavour is directly related to the volatile compounds produced during roasting, the objective of the present study was to perform a comparative evaluation of the volatile fraction of defective (black, immature, sour) and healthy coffee beans, in order to find possible chemical markers for detection of defective coffee beans in roasted coffee. Volatiles extraction and concentration was performed by solid phase micro-extraction (SPME) of the roasted coffee headspace, using a triple phase (divinylbenzene/carboxen/polydimethylsiloxane) fiber. Analysis of the volatile profiles was performed by GC–MS. The results obtained showed that the proposed methodology was adequate for extraction, concentration and analysis of the coffees volatile profile. Several substances were identified as possible markers for differentiating black, sour and immature beans from healthy coffee beans. Statistical analysis of the data by principal components (PCA) demonstrated that the volatile profile enables the differentiation of healthy and defective coffees. The data were separated into two major groups, one represented by immature and black beans and the other by healthy and sour coffee beans. Such results indicated that black and sour beans can be associated to fermentation of immature and of healthy beans, respectively.     

岛津GCMS在农残分析中的最新应用技术

介绍了岛津公司针对食品、农产品安全开发的三种最新应用技术：高选择性负化学离子化谱库的开发和应用；应对突发事件和满足食品安全快速检测要求的数据库-Compound Composer；应对难分离组分进行确认的双柱GCMS系统及应用。为食品、农产品安全提供了高灵敏度、高选择性、快速准确、高分离效能的解决方案。     

GC-MS用于花果香气成分研究进展

香气是衡量花果品质的重要感官指标,决定着花果制品的风味和加工特性。不同的花果具有特殊的香气成分,通常由挥发性有机化合物(volatile organic compounds,VOCs)组成,VOCs是一类分子量较小的次生代谢产物。VOCs可由气相色谱-质谱(gas chromatography-mass spectrometer,GC-MS)联用技术进行检测与分析。目前,国内外学者对不同种类花果的香气成分研究有很多报道,但对其香气成分的检测方法及成分对比未进行归纳总结。该文综述目前国内外花果香气成分的检测方法、香气成分的主要组成和功能特性,以期对花果香气成分研究的未来发展趋势进行预测,为花果香气成分的研究提供参考。     

P＆T-GC/MS分析水箱水中挥发性有机物的污染

用P&T -GC/MS分析自来水中异味的原因。通过谱库检索结合标样保留时间定性发现水质受到苯系物污染。进一步分段调查 ,确定了污染源来自水箱内壁采用的粘结剂和有机涂层     

多维气相/气质联用法测定葡萄酒中的氨基甲酸乙酯

建立了多维气相/气质联用（MDGC/GCMS）法测定葡萄酒中氨基甲酸乙酯的检测方法。采用硅藻土固相萃取柱对葡萄酒中氨基甲酸乙酯（EC）进行提取净化,利用MDGC/GCMS对葡萄酒中EC进行检测。结果表明,葡萄酒中EC与干扰物均得到很好分离,EC在0～1 000 μg/L范围内线性关系良好（R=0.999 3）,检出限（S/N=3）为1.0 μg/L,加标回收率为82.97%～86.82%,相对标准偏差（RSD）为2.29%;方法的精密度和重复性试验RSD分别为2.42%和2.88%。表明该方法准确度高、重复性和精密度良好,适用于葡萄酒中的氨基甲酸乙酯的检测。     

固化涂层中有机挥发物的顶空法和萃取法检测结果的一致性探讨

通过顶空-气相色谱质谱法和加速溶剂萃取(ASE)-气相色谱质谱法对溶剂型涂料固化后残留的代表性有机挥发物进行检测,并对所得数据通过数理统计进行比对研究,结果表明:这两种方法没有明显的差别。