共查询到20条相似文献,搜索用时 16 毫秒
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建立双柱串联–便携式气相色谱测法定室内空气中苯系物的方法。利用仪器内部自带的Tenax吸附剂在0.5 L/min流量下采集空气样品100 s,然后仪器迅速升温至400℃左右,对吸附剂进行热解吸进样,以微亚离子检测器(MAID)对室内空气中7种苯系物进行测定。结果表明,色谱条件为MXT–200/MXT–WAX金属毛细管柱串联色谱柱,柱温90℃,柱压103 425 Pa时,分离效果最好,且运行时间短。各组分在19.26~306.7μg/m~3范围内与色谱峰面积的平方根线性关系良好,相关系数r大于0.995。方法检出限为6.40~15.9μg/m~3,空白加标回收率为92%~114%,测定结果的相对标准偏差为6.1%~13.7%(n=6)。采用双柱串联便携式气相色谱法测定室内空气中苯系物具有快速、准确、方便等优点。 相似文献
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大气及污染源排放气体中苯系物气相色谱测定 总被引:1,自引:0,他引:1
建立了气体样品中不同浓度的苯系物的分析方法,优化了测定的操作条件,提出了保证测定质量的技术关键。方法已用于污染源及环境空气中苯系物的气相色谱测定。 相似文献
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<正>不久前,环保部就《水质硝基酚类的测定气相色谱–质谱法》(征求意见稿)《、水质二氧化氯的测定碘量法》(征求意见稿)两项国家环境保护标准发布征求意见的函。其中,《水质硝基酚类的测定气相色谱–质谱法》为首次发布,《水质二氧化氯的测定碘量法》则是对HJ551–2009《水质二氧化氯的测定碘量法(暂行)》的修订。硝基酚类是危害环境的有机污染物,可在水生生物和人体中残留和浓缩,具有高毒性和致癌性,4-硝基酚被我国列入环境优先监测污染物监测名单中,但目前我国尚没有关于 相似文献
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树脂富集—气相色谱法测定水中痕量苯系物 总被引:1,自引:0,他引:1
王永强 《广东微量元素科学》1996,3(8):45-47
用国产GDX树脂作吸附剂富集,气相色谱法测定了水中痕量苯系物,结果良好。 相似文献
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食品包装材料上油墨中残留烷基苯成分分析及其迁移性的GC-MS研究 总被引:6,自引:0,他引:6
建立了一种食品包装材料上多色油墨中残留烷基苯成分的提取和气相色谱-质谱联用(GC-MS)分析方法. 采用选择离子检测(SIM)模式, 以内标定量法对某些食品包装材料上多色油墨中烷基苯残留量进行了准确定量分析. 对油墨中残留烷基苯向食品中迁移的初步研究结果表明, 包装材料上油墨中的苯及苯系物等有害物质可能透过薄膜进入食品而造成污染. 相似文献
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Nucleic acid sensing analysis has been widely applied to the fields of food quality control, environmental monitoring, and medical diagnosis. A key step in developing effective DNA-based electrochemical biosensors is to obtain a biorecognition layer on the biosensor, which can be influenced by many factors. Hence, we constructed a series of HJ24 layers on highly oriented pyrolytic graphite to investigate the relation between the configuration of the adsorbed probe HJ24 and the redox property using atomic force microscopy and voltammetry. We used HJ24 for its diagnostic value as it specifically recognizes the SH2 domain-containing phosphatase, a critical contributor in many important signaling pathways. The results demonstrated that increasing K ions induced G-quartet oxidation peak occurrence/increase([K+]?400 mmol/L), and also resulted in the formation of more compact single strand sheets([K+]?300 mmol/L). Moreover, transitions of molecule configurations and redox currents of G-quartets were observed at low concentration [K+]=12 mmol/L, which may indicate the appearance of new configurations under this condition. Besides, by analyzing atomic force microscopy(AFM) images, it was found that the different adsorbed configurations are correlated with the HJ24 concentration, the basal configuration, and the linker group on the HJ24 sequence. This information may be useful for understanding the adsorption process of HJ24 as well as for the further development of practical applications for HJ24 films on DNA electrochemical sensors, and may ultimately help improve the diagnosis and treatment of patients with SHP2-related diseases. 相似文献
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Vicarious nucleophilic substitutions (VNS) of hydrogen in 1-nitro-4-(pentafluorosulfanyl)benzene with carbanions provide 2-substituted 1-nitro-4-(pentafluorosulfanyl)benzenes in good to high yields. VNS of 1-nitro-3-(pentafluorosulfanyl)benzene gives a mixture of 6- and 4-substituted 1-nitro-3-(pentafluorosulfanyl)benzenes in 85:15 to >98:2 ratio and good to high yields. In basic media, the VNS reactions lead to the formation of carbanions that can be alkylated by alkyl halides affording the corresponding alkylated products in moderate yields. Transformation of primary products to substituted (pentafluorosulfanyl)anilines and 3- or 4-substituted (pentafluorosulfanyl)benzenes is also described. 相似文献
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Omelchenko Irina V. Shishkin Oleg V. Gorb Leonid Hill Frances C. Leszczynski Jerzy 《Structural chemistry》2012,23(5):1585-1597
Structural Chemistry - Geometrical parameters, aromaticity, and conformational flexibility of the set of polysubstituted benzenes with different number and position of nitro and amino groups were... 相似文献
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Jolanta Ignatowska 《Journal of fluorine chemistry》2007,128(9):997-1006
Sodium dithionite initiated addition of CF2Br2, CF3I and (CF3)2CFI to the terminal double bond of allylbenzenes and of (CF3)2CFI to allylpyridines in a MeCN/H2O system were investigated. The reactions of CF2Br2 with allylbenzenes gave comparable amounts of adducts, 1-(2,4-dibromo-4,4-difluorobutyl)benzenes, debrominated products,1-(4-bromo-4,4-difluorobutyl)benzenes, and dimeric compounds in total yields 40-66%. Treatment of the adducts with DBU resulted in double dehydrohalogenation affording 4-aryl-1,1-difluorobutadienes which undergo Diels-Alder condensation with nitrogen dienophiles to give N-heterocycles with difluoromethylene group in the ring. The reactions of CF3I and (CF3)2CFI with allylbenzenes gave the respective adducts, (4,4,4-trifluoro-2-iodobutyl)benzenes and 1-(4,5,5,5-tetrafluoro-4-(trifluoromethyl)-2-iodopentyl)benzenes as the main products. Dehydrohalogenation of these adducts resulted, respectively, in (4,4,4-trifluoro-but-1-enyl)benzenes and 4-aryl-1,1-bis(trifluoromethyl)butadienes in high yields. (CF3)2CFI reacted rapidly with allylpyridines to give mixtures from which, after treatment with DBU, 4-pyridyl-1,1-bis(trifluoromethyl)butadienes were isolated in a ca. 60% yield. 相似文献
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4-Diazo-1,2,3-triazoles thermolyze and photolyze to 4-1,2,3-triazolylidenes which (1) convert benzenes to 4-phenyl-1,2,3-triazoles or/and (2) isomerize to α-diazonitriles which react carbenically with benzenes by addition, ring-expansion or substitution processes. 相似文献
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Using an approximation method, the dissociation constants of HJ, FSO3H and CF3SO3H in glacial acetic acid could be derived from conductivity measurements: $$K_{diss}^{HJ} = 10^{ - 5,8_, } K_{diss}^{FSO_3 H} = 10^{ - 6,1} and K_{diss}^{CF_3 SO_3 H} = 10^{ - 4,7} $$ These values show CF3SO3H to be the strongest known acid in glacial acetic acid, HJ to be slightly weaker than HBr and FSO3H intermediate between HJ and H2SO4. 相似文献