烟草叶片分泌物及植株挥发物释放规律研究

烟草次生物质不仅对多种害虫的定向、产卵等行为具有调控作用,还能吸引天敌进行间接防御。本研究利用溶剂漂洗法提取了烟草旺长期和成熟期的叶片分泌物,利用顶空吸附法收集了烟草旺长期植株的挥发物,并利用气相色谱(GC)/质谱(MS)联用技术测定了烟草次生物质的成分及含量。结果表明,烟草叶片分泌物中共检测出36种化合物,其中旺长期有33种,成熟期有31种。烟草旺长期植株挥发物中共检测出48种挥发物组分。其中36种组分的日周期释放规律表现为随光照加强和温度升高,释放量呈现上升趋势;11:00-15:00时段的释放量显著高于其他各个时段(P0.05)。而其中9种组分表现为在夜间的释放量显著升高。     

阿尔泰瑞香提取物的体外抗炎及抗氧化活性

目的 探讨阿尔泰瑞香二氯甲烷提取物（Da-Dm）的体外抗炎及抗氧化活性。方法 以不同浓度（1、6、30 μg/mL）的Da-Dm作用于脂多糖（LPS,1 μg/mL）诱导的RAW264.7小鼠巨噬细胞,采用CCK-8法测定Da-Dm对细胞增殖的影响;Griess法检测细胞上清液中一氧化氮（NO）的释放量;ELISA法检测细胞上清液中肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）的分泌量。以维生素C为对照,采用FRAP法、DPPH法评价Da-Dm总抗氧化能力。结果 Da-Dm在浓度为30 μg/mL及以下时对RAW264.7细胞增殖没有影响。与LPS组比较,1~30 μg/mL的Da-Dm可明显降低LPS诱导的RAW264.7细胞分泌炎症因子NO、IL-1β、IL-6和TNF-α的含量（P<0.05,P<0.01）,并呈现浓度依赖性。Da-Dm对DPPH自由基有较好的清除能力,其清除率的IC50为318.1 μg/mL,在FRAP实验中其对Fe²⁺离子具有较强的还原能力。结论 Da-Dm可以抑制LPS诱导的RAW264.7细胞炎症反应,它的抗炎作用可能与抑制NO、IL-1β、IL-6和TNF-α的释放有关。Da-Dm具有较好的抗氧化活性。     

甲醇和二氯甲烷提取小麦中吡虫啉的比较研究

分别用二氯甲烷和甲醇提取小麦植株中的吡虫啉,添加回收率结果表明,甲醇提取吡虫啉添加回收率64．68～97．15％,低于二氯甲烷提取吡虫啉添加回收率102．25-105．24％;测定小麦中吡虫啉含量时二氯甲烷提取吡虫啉的量高于甲醇提取的量,为甲醇提取量的10-12倍：用二氯甲烷提取吡虫啉比甲醇提取吡虫啉操作简单,提取杂质少,可以作为小麦植株中吡虫啉提取的快速高效的溶剂。     

Method Dependency in the Measurement of BTEX Levels in Contaminated Soil

Environmental consultants and analytical laboratories are increasingly realizing the importance of analytical method selection and validation for the reliable measurement of soil contamination. Aromatic hydrocarbons (BTEX) is one class of environmentally significant soil contamination for which testing is required by regulatory authorities in most industrialized countries. Unfortunately, in most guidelines there is a lack of direction for the selection of a testing method for BTEX and, in practice, any one of a variety of methods may be employed. The fact that these may not all yield comparable results is a source of much frustration in the industry and there is a paucity of published research into this problem. In a number of carefully controlled experiments, the method dependency of measured BTEX levels in contaminated soil samples has been investigated. Three commonly employed methods, namely, (methanol extraction) purge-and-trap/gas chromatography with mass selective detection (P&T/GCMSD), headspace/GCMSD and dichloromethane (DCM) extraction/gas chromatography with flame ionization detection (GCFID) have been compared in the analysis of 109 gasoline-contaminated soil samples collected from station sites in Melbourne, Australia. Measurable BTEX concentrations were recorded in 92% of the samples using P&T/GCMSD, 59% using DCM/GCFID, and 40% using headspace/GCMSD. Correspondingly, the magnitudes of the recovered concentrations were significantly higher by P&T/GCMSD than by DCM/GCFID, which in turn were significantly higher than the magnitudes determined by headspace/GCMSD. These trends are evident for both clay and sandy soils. These studies clearly demonstrate that, for the three commonly employed methods described, measured BTEX levels are extraction and analytical method dependent in at least two different soil types.     

萃取溶剂对饲料香味剂有效成分分析的影响

采用无水乙醇、正己烷、二氯甲烷萃取同一饲料香味剂,通过气相色谱进行检测,并用外标法对其中的有效成分进行定量,对比3种不同溶剂的回收率.结果表明,对饲料香味剂中主要成分的回收率以二氯甲烷最高.     

甲胺磷在二氯甲烷溶剂中稳定性研究结果初报

二氯甲烷是农药残留前处理方法中常用于甲胺磷残留提取的溶剂,但试验发现,低浓度甲胺磷会在二氯甲烷溶剂中迅速降解,2.1mg/L的甲胺磷二氯甲烷溶液中甲胺磷在配制后7h全部降解,而同样浓度的甲胺磷在丙酮中则相当稳定,463h后仍未见降解迹象。     

在二氯甲烷溶液里〔Cu(CH_3CN)_4〕〔MF_6〕与碘化四丁铵的反应

在本实验中,研究了［Ｃｕ（ＣＨ３ＣＮ）４］［ＭＦ６］（Ｍ＝Ｍ０或Ｗ）与碘化四丁铵（Ｃ４Ｈ９）４ＮＩ在二氯甲烷（ＣＨ２Ｃｌ２）中的反应。研究结果表明,在ＣＨ２Ｃｌ２里,（Ｃ４Ｈ９）４ＮＩ未能把［Ｃｕ（ＣＨ３ＣＮ）４］［Ｍ０Ｆ６］和［Ｃｕ（ＣＨ３ＣＮ）４］［ＷＦ６］中的Ｍ０Ⅴ和ＷⅤ还原成Ｍ０Ⅳ和ＷⅣ盐。通过分析得知,反应产物是ＣｕＩ和（Ｃ４Ｈ９）４ＮＭＦ６,配位体ＣＨ３ＣＮ被解脱出来,反应中并没有产生Ｉ２。     

一种20%氯虫苯甲酰胺悬浮剂的液相色谱检测方法的研究

为研究筛选出一种高效液相色谱技术检测20%氯虫苯甲酰胺悬浮剂的最佳方法,首先通过液相色谱检测不同浓度的标准品建立标准曲线(y=2.9×105x-1.8×106,R2=0.9999),然后通过对5 种不同提取剂（甲醇、乙醇、乙腈、苯酮、二氯甲烷）的提取样品后液相色谱结果进行比较研究,筛选出其中较好的提取试剂-二氯甲烷,并且其最佳浓度为55%（20%氯虫苯甲酰胺悬浮剂-康宽的检出浓度为931.4 μg/mL）。研究建立了一种氯虫苯甲酰胺最佳液相色谱方法（在常规的液相色谱条件下,以55%的二氯甲烷提取）,为氯虫苯甲酰胺后续的残留以及消解等方面研究提供了参考。     

二氯甲烷萃取绿茶咖啡碱工艺参数的优化

为探寻从绿茶中提取咖啡碱的工艺,以二氯甲烷为萃取剂,以咖啡碱得率与纯度为考察指标,采用单因素试验得出较佳茶汤质量分数、料液比(茶汤与二氯甲烷的体积比)、摇匀时间、静置萃取时间、萃取温度、萃取次数和茶汤pH值,选取料液比、摇匀时间、静置萃取时间、萃取温度等4个主要影响因素设计正交试验,并对正交试验结果进行验证.结果表明,...