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建立了固相微萃取/气相色谱-质谱联用法(SPME/GC-MS)测定橡胶密封材料中N-亚硝基-N-甲基苯胺(NMPh A)、N-亚硝基-N-乙基苯胺(NEPh A)和N-亚硝基二苯基胺(NDPhe A)3种N-亚硝胺化合物含量的方法。样品参考国标GB/T 24153-2009进行预处理后,采用固相微萃取进行提取,对影响固相微萃取效率的纤维涂覆种类、萃取时间、搅拌速度和萃取温度等条件进行优化。在优化条件下,方法的线性范围为5~500μg/L,相关系数(r)均大于0.99,检出限为0.5μg/kg,回收率为77%~92%,相对标准偏差(RSD,n=6)为3.8%~7.7%。 相似文献
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气相色谱-离子阱串联质谱法测定人参中五氯硝基苯及其代谢产物残留 总被引:2,自引:0,他引:2
为了快速检测和确证人参中五氯硝基苯及其代谢物的残留量,建立了气相色谱/离子阱串联质谱法(GC-MS/MS)同时测定人参中五氯硝基苯(PCNB)及其2种代谢产物五氯苯胺(PCA)和甲基五氯苯硫醚(PC-TA)残留分析方法。样品用正己烷均质提取,弗洛里硅土固相萃取柱(Florisil-SPE)净化,采用GC-MS/MS多反应监测模式(MRM)检测,外标法定量。在人参中五氯硝基苯和五氯苯胺检出限均为1 ng/g,甲基五氯苯硫醚为0.1 ng/g;在0.01~0.5μg/g添加范围内,五氯硝基苯、五氯苯胺和甲基五氯苯硫醚的添加回收率分别为82.2%~89.4%、82.3%~84.7%和84.1%~88.5%;相对标准偏差均小于8.6%;检出限保持在0.1~1ng/g之间(信噪比10)。 相似文献
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采用CWX/DVB萃取头,应用固相微萃取与高效液相色谱联用技术(SPME/HPLC)分析了水溶液中的痕量微囊藻毒素。对SPME的萃取条件进行了优化,并对实际水样进行了分析。该方法测定MC-LR(LR型微囊藻毒素)的线性范围为1.00~200μg/L,相关系数为0.999 5,检出限为0.45μg/L(3σ,n=11),相对标准偏差(RSD)为2.4%,回收率为90%~99%。该方法测定MC-RR(RR型微囊藻毒素)的线性范围为1.00~100μg/L,相关系数为0.998 8,检出限为0.15μg/L(3σ,n=11),RSD为2.4%,回收率为89%~100%。 相似文献
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建立了固相微萃取/气相色谱-质谱(SPME/GC-MS)测定沥青基防水涂料中18种多环芳烃(PAHs)迁移量的方法。研究了萃取涂层、萃取时间、搅拌速度及萃取温度对萃取效果的影响。在优化条件下,18种PAHs在1~100μg/L范围内呈良好的线性关系,相关系数(r)为0.992 8~0.998 9,检出限为0.03~0.09μg/L;在1、10、100μg/L加标水平下的平均回收率为71%~94%,相对标准偏差(RSD,n=6)为2.8%~8.6%。对5份沥青基防水涂料进行迁移实验,发现迁移液中均检出PAHs,且主要为四环以下的PAHs。实验表明该方法适应于沥青基防水涂料中18种PAHs的迁移量检测。 相似文献
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建立了固相萃取/液相色谱-串联质谱检测水中18种苯胺类化合物的分析方法,并优化了固相萃取和色谱条件。水样经混合型阳离子交换柱(MCX)或硅胶基体阳离子交换柱(SCX)富集后,用氨水甲醇溶液洗脱,用超纯水适当地稀释后,用液相色谱-串联质谱法测定。以ODS柱为分离柱,甲醇-0.005%(v/v)甲酸水溶液为流动相,梯度洗脱,多反应监测模式分析,内标法定量。18种苯胺类化合物的分析时间在15 min之内。采用MCX柱萃取时,16种苯胺化合物的方法检出限为0.002~0.035 μ g/L,地表水样品的加标回收率为72.5%~92.5%,相对标准偏差为1.4%~9.6%;采用SCX柱萃取时,17种苯胺类化合物的方法检出限为0.013~0.207 μ g/L,地表水样品的加标回收率为66.5%~102%,相对标准偏差为2.4%~13.6%。本实验还考察了消除基质干扰的5种方法,结果表明,调整色谱分离条件是最有效的方法,其次是选择合适的前处理方法。更换离子源、内标法定量和利用基质标准溶液校正也可在一定程度上消除或补偿基质干扰。 相似文献
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建立了用气相色谱-质谱(GC-MS)联用法测定水产品中19种氯代酚及其钠盐的分析方法。试样用H_2SO_4消解后,用环己烷-乙酸乙酯提取酸解液中的氯代酚,利用酚类易溶于稀碱溶液的性质,将氯代酚提取到稀碱液中,调稀碱液pH至微酸性,用二氯甲烷-正己烷溶液萃取,无水Na_2SO_4脱水,浓缩定容并硅烷化衍生后,用GC-MS仪EI源选择离子模式检测,氘代4-氯-3-甲基酚(PCMC-d_2)和氘代2,4,6-三溴苯酚(2,4,6-TBP-d_2)为内标,内标法定量。氯代酚在2.0~70.0μg/L范围内,其浓度和峰面积呈良好的线性相关(r≥0.999);水产品中添加量为1.00μg/kg、2.00μg/kg、3.00μg/kg和7.00μg/kg时,回收率一氯酚(MCP)为55.2%~88.8%,二氯酚(DCP)为63.0%~114%,三氯酚(TCP)为76.0%~116%、四氯酚(TeCP)为78%~125%,五氯酚(PCP)为83.2%~104%;方法检出限在0.2~0.4μg/kg之间。 相似文献
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建立了液液萃取-气相色谱-质谱(GC-MS)联用测定废水中N-甲基甲酰苯胺(NMF)、N-甲基苯胺(NMA)和甲酰苯胺(FA)的分析方法。考察了萃取溶剂、盐加入量和pH等影响萃取效果的参数。结果表明,当以二氯甲烷为萃取剂,将pH调至11.85,15%NaCl溶液加入量为1%(体积比)条件下,NMF、NMA和FA的萃取效果最佳。以N,N-二乙基苯胺(DEA)为内标,在GC-MS选择离子模式下测定NMF、NMA和FA,该方法对三种目标物的平均回收率为97.5%~101.0%,相对标准偏差为4.3%~6.3%(n=6),检测限(S/N=3)为0.0018~0.0023μg/L,测得某废水样品中NMF、NMA和FA的含量依次为0.94±0.08、0.14±0.02和0.12±0.02g/L。 相似文献
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建立了加速溶剂萃取/液相色谱-串联质谱分析底泥中氯硝柳胺及其降解产物(5-氯水杨酸和2-氯-4-硝基苯胺)的方法。以中性氧化铝作为池内吸附材料,集提取和净化于一步,乙腈-水(3∶1,体积比)作为萃取溶剂,优化了温度和静态萃取时间等参数。在优化条件下,氯硝及其降解产物在0.1~20.0μg/L范围内有良好线性关系,相关系数(r)均大于0.999。方法的检出限和定量下限分别为0.04~0.1μg/kg和0.2~0.5μg/kg。用于底泥中氯硝柳胺及其降解产物的分析,在0.5、1.0、2.0μg/kg加标水平下,平均加标回收率为93.5%~101.9%,相对标准偏差为3.7%~6.7%。该方法简便,灵敏度高,重现性好,可应用于实际样品分析。 相似文献
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固相微萃取气相色谱法测定水产品中五氯苯酚及其钠盐残留量 总被引:2,自引:0,他引:2
采用自动固相微萃取(Automated SPME)超声波辅助萃取技术(UE)与气相色谱联用测定水产品中五氯苯酚及其钠盐残留量.实验优化了SPME直接萃取技术,样品调pH 2,超声波40℃萃取30 min后,用85μm聚丙烯酸酯(PA)萃取头90℃自动搅拌萃取30 min,270℃解吸5 min.最低检出量为0.01μg/kg;五氯苯酚线性范围0.001~10 μg/L,r=0.9999;对鳕鱼加标五氯苯酚1.0、5.0μg/kg回收率分别为71.0%~80.0%、77.2%~91.4%,相对标准偏差(RSD)为6.3%和8.6%(n=3).该方法简便、灵敏、稳定,无溶剂污染,是测定水产品中五氯苯酚及其钠盐残留量的理想方法. 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL. 相似文献
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A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions. 相似文献