Detection of Polynuclear Aromatic Hydrocarbon Diol Epoxide-Derived DNA and Globin Adducts in Humans by Gas Chromatography-Mass Spectrometry

Gas chromatography-negative ion chemical ionization-mass spectrometry-selected ion monitoring (GC-NICI-MS-SIM) was employed to detect tetramethyl ether derivatives of tetraols released upon hydrolysis of DNA and globin adducts derived from diol epoxides of polynuclear aromatic hydrocarbons (PAH). The methodology involves the following steps: 1) isolation of DNA or globin; 2) mild acid hydrolysis under vacuum; 3) isolation of the resulting tetraols and derivatization to the corresponding tetramethyl ethers using CH₃I; 4) HPLC purification followed by GC-NICI-MS-SIM analysis. Analysis of human globin samples by this method indicates the presence of adducts which release chrysene-1,2,3,4-tetraol and benzo[a]pyrene-7,8,9,10-tetraol in smokers and nonsmokers. The level of BP-diol epoxide globin adducts in smokers was significantly higher than that in nonsmokers (2.75 vs 0.96 fmol/mg globin). The concentration of chrysene diol-epoxide globin adducts in the same subjects was about two orders of magnitude greater than that of BP-diol epoxide adducts. BP-diol epoxide DNA adducts have also been identified in surgical specimens of human lung tissue.     

Monitoring of Polycyclic Aromatic Hydrocarbons in Water during Preparation Processes

This article presents results on investigation of quantitative changes of polycyclic aromatic hydrocarbons (PAHs) during water treatment processes. PAHs constitute one of several classes of organic pollutants consisting of three or more fused benzene rings. Many of them are quite persistent and some are known to be carcinogens. That is why presentation of quantitative PAHs changes in water during preparation processes is very important. In Polish legislation and European Union law there are recommendations for PAHs concentration in drinking water. The limit value of the sum of 4 PAHs (benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, indeno[1,2,3-cd]pyrene) is 100 ng/L. Limit concentration of benzo[a]pyrene defined in regulations (Polish and UE) is 10 ng/L. The purpose of the present study was to determine changes of concentrations of PAHs in various stages of water treatment process and comparison the values of this index with the limits specified in valid Minister of Health Regulation and Council Directive 98/83/EC. A total concentration of 16 PAHs in the investigated water treatment processes was in the range of 39–204 ng/L. The maximum level was recorded for water after intermediate ozonation. In different water treatment processes were observed fluctuations in PAHs concentrations. Decreased values were recorded among others after pre-ozonation and coagulation and after sedimentation process. Increase of PAHs level occurred after filtration through sand filters. Concentrations of 4 PAHs in drinking water is much below the limit value defined in Polish and UE legislation. Concentration of 16 PAHs in water after final chlorine-disinfection also meets the requirements of the regulation for 4 PAHs.     

QuEChERS法萃取-气相色谱-三重四级杆串联质谱法快速测定果蔬中58种农药残留

以QuEChERS法为前处理方法,采用气相色谱-三重四级杆串联质谱检测技术,建立了蔬菜水果中58种农残的快速测定方法。果蔬样品以乙腈作为提取溶剂,用QuEChERS法进行前处理。在气相色谱分离中用HP-5MS毛细管色谱柱为固定相,在质谱分析中采用多重反应监测模式。这58种农药的质量分数均在0.01mg/kg～1mg/kg内与其对应的峰面积呈良好的线性关系,方法的检出限(3S/N)为0.01～2.5μg/kg,定量限(10S/N)为0.06～10μg/kg。以空白样品为基质进行3个水平的加标,回收率在62%～138%之间,相对标准偏差为1.97～17.26%。本方法简便、快速、灵敏度高,可用于果蔬中多种农药残留的筛查和检验。     

中性氧化铝固相萃取柱在柴油分析中应用

使用中性氧化铝固相萃取柱(SPE)对柴油中的饱和烃和芳烃组分进行了有效的分离,并用气相色谱-质谱联用仪分析了加入内标液的饱和烃、芳烃组分,数据显示该柱可以满足柴油组成的现场实验,符合测试标准的SPE柱分离效率小于5%要求。     

合成大麻素类毒品的结构衍变与质谱解析

合成大麻素毒品蔓延趋势严峻,我国政府启动了整类列管政策。该类毒品结构变异较强,对重点目标结构的识别以及共性质谱特征的汇总在司法实践中具有重要意义。本文解析了该类毒品的结构衍变规律,遴选27种合成大麻素,采用气相色谱 质谱联用法（GC MS）采集EI MS数据。实验结果表明,合成大麻素类物质主要由母核、链接、取代基和侧链四部分构成。其中,吲哚/吲唑母核易产生m/z 144、145特征碎片;链接部分的碎裂主要发生在羰基两侧;取代基上的叔碳原子、丁酸甲酯以及丁酰胺易发生多元化碎裂;侧链易发生中性丢失而产生氟丁基（m/z 74）、氟戊基（m/z 88）和戊烯基（m/z 68）等特征碎片。该碎裂途径的推断可为未知新型合成大麻素类物质的判别提供参考。     

Chromenes from Ageratum conyzoides: Steam distillation,supercritical extraction,and mathematical modeling

The chromenes extraction processes from Ageratum conyzoides by steam distillation and supercritical fluid extraction (SFE) were studied. Essential oil was extracted by saturated steam at 1.0 to 2.0 bar and the SFE was performed at 40ºC and 90 to 200 bar to obtain non-volatile extracts. The essential oil presented two major compounds—precocene I (28.24%) and precocene II (28.55%). At 90 bar, the SFE resulted in higher yield and selectivity for precocene I and II (65.06%). The yield of chromenes varied according to pressure of SFE; however, this behavior was not observed in extracts obtained by steam distillation.     

The Impact of Soy Isoflavones on MCF-7 and MDA-MB-231 Breast Cancer Cells Using a Global Metabolomic Approach

Despite substantial research, the understanding of the chemopreventive mechanisms of soy isoflavones remains challenging. Promising tools, such as metabolomics, can provide now a deeper insight into their biochemical mechanisms. The purpose of this study was to offer a comprehensive assessment of the metabolic alterations induced by genistein, daidzein and a soy seed extract on estrogen responsive (MCF-7) and estrogen non-responsive breast cancer cells (MDA-MB-231), using a global metabolomic approach. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that all test compounds induced a biphasic effect on MCF-7 cells and only a dose-dependent inhibitory effect on MDA-MB-231 cells. Proton nuclear magnetic resonance (¹H-NMR) profiling of extracellular metabolites and gas chromatography-mass spectrometry (GC-MS) profiling of intracellular metabolites confirmed that all test compounds shared similar metabolic mechanisms. Exposing MCF-7 cells to stimulatory concentrations of isoflavones led to increased intracellular levels of 6-phosphogluconate and ribose 5-phosphate, suggesting a possible upregulation of the pentose phosphate pathway. After exposure to inhibitory doses of isoflavones, a significant decrease in glucose uptake was observed, especially for MCF-7 cells. In MDA-MB-231 cells, the glutamine uptake was significantly restricted, leading to alterations in protein biosynthesis. Understanding the metabolomic alterations of isoflavones represents a step forward in considering soy and soy derivates as functional foods in breast cancer chemoprevention.     

杀虫气雾剂中未经登记农药成分的检测

采用气相色谱-质谱联用定性,液相色谱定量检测杀虫气雾剂样品中未经登记的农药成分。结果显示,市售杀虫气雾剂质量参差不齐,部分产品违规添加氯烯炔菊酯和氯菊酯,部分产品甚至未检测出登记农药成分。     

气相色谱-质谱法快速检测方便面中DEHP

对方便面中邻苯二甲酸二(2-乙基己基)酯(DEHP)的含量进行系统地研究,建立方便面中DEHP含量快速测定的气相色谱-质谱(GC-MS)检测方法。以甲醇为萃取剂超声波辅助萃取,考察超声萃取的温度和时间,着重研究试验过程可能存在的干扰情况。在试验选定的条件下,样品加标回收率为92.3%～102.3%,相对标准偏差小于3.4%。该方法具有快速、准确度高、干扰少等优点,适合于方便面中DEHP含量的测定。     

宁夏滩羊背最长肌挥发性物质的组成分析

[目的]探究宁夏滩羊肉背最长肌挥发性风味物质组成,为滩羊肉生产加工提供理论参考。[方法]采用固相微萃取(SPME)技术并结合GC-MS分析,对宁夏滩羊肉背最长肌挥发性化合物进行了分析和定量。[结果]共检测到65种化合物,以烃类和醛类化合物为主体,其相对含量分别占34.887%和34.682%。[结论]醛类化合物可能是滩羊背最长肌风味物质的主体成分,对宁夏滩羊贡献风味的挥发性物质可能为壬醛、癸醛、肉豆蔻醛、2-十一烯醛、反式-2-癸烯醛、丙位十二内酯、邻苯二甲酸二甲酯、月桂醇、法呢醇等9种挥发性风味物质。