共查询到20条相似文献,搜索用时 62 毫秒
1.
液相色谱-氢化物发生-原子荧光联用同时测定洛克沙胂及其代谢物 总被引:4,自引:0,他引:4
利用液相色谱-氢化物发生-原子荧光联用技术同时检测5种砷形态化合物(亚砷酸、砷酸、一甲基胂酸、二甲基胂酸和洛克沙胂).结果表明,在梯度洗脱条件下,以C18反相柱作分离柱,含0.5 mmol/L四丁基溴化铵的NaH2PO4-CH3OH溶液为流动相,5种砷化合物得以完全分离;以20 g/L K2S2O8为氧化剂进行紫外消解,7% HCl为载流,20 g/L KBH4为还原剂,砷化合物形成最佳的原子荧光信号.5种砷化合物在一定的浓度范围内与荧光峰面积呈良好的线性关系; 检出限<10 μg/L; 加标回收率为81.4%~105.6%; 相对标准偏差RSD<4.0%.本方法适用于饲料、鸡粪、土壤和植物样品中洛克沙胂及其代谢物(亚砷酸、砷酸、一甲基胂酸和二甲基胂酸)的含量分析. 相似文献
2.
氢化物发生—冷阱捕获—色谱分离—原子吸收法测定天然水中坤的形态 总被引:10,自引:0,他引:10
研究建立了氢化物发生-冷阱捕获-色谱分离-原子吸收方法测定天然水中四种主要砷形态,测试系统自行组装,色谱柱填料采用ChromosorbGAW-DMCS(粒径0.3~0.45mm),其上涂布3%OV-101。方法的检出限以砷计分别为:As(V)0.51ng,As(Ⅲ)0.43ng,MMA0.38ng,DMA0.67ng;12ng砷标准偏差为As(Ⅴ)4.21%,As(Ⅱ)3.56%,MMA3.23% 相似文献
3.
4.
用气相色谱-微波等离子体-原子发射光谱检测器(GC-MIP-AES)测定水中微量无机砷,在酸性条件下,As(Ⅲ与2,3-二巯基丙醇(BAL)的反应生成挥发性的环状二硫胂衍生物,被甲苯萃取,在181.379nm和189.041nm处GC-MIP-AES分别检测衍生物中硫砷的发射信号,检出限为15pg(以砷计)加标回收率96.35-106.03%,变异系数〈4.5%。 相似文献
5.
利用一维和二维NMR技术,对含有手性膦配体甲基-3脱氧-3(二苯膦基)-4,6-氧-苄叉基-α-D一吡喃阿卓糖苷(3-MBPA)和甲基-2-脱氧-2-(二苯膦基)-4,6-氧-苄叉基-α-D-吡喃阿卓糖苷(2-MBPA)的钯配合物trans—[Pd(3-MBPAH)2CI2」(1),trans-[Pd(2-MBPAH)2CI2](2)和cis-[Pd(3-MBPA)2](3),cis-[Pd(2-MBPA)2](4)进行~1H和~(13)C NMR谱分析,归属了全部的~1H和~(13)C NMR谱线,并根据磷的化学位移及Raman谱确定化合物(3)和(4)是顺式构型,对实验中的一些现象也做了简单讨论。 相似文献
6.
鳙鱼心中电子载体泛醌化合物的研究 总被引:1,自引:1,他引:0
鳙鱼(Aristichthysnobilis)心脏提取物经硅胶柱色谱分离、制备薄层色谱纯化,得到二种泛醌化合物,用NMR、IR、MS、UV、HPLC、TLC等现代测试技术测定其化学结构为2,3-二甲氧基-5-甲基-6-10聚异戊二烯基-1,4-苯醌(Ⅰ)和一种未见报道的新泛醌酯——2,3-二甲氧基-5-甲基-6-甲酯基-八聚异戊二烯基-1,4-苯醌(Ⅱ)。 相似文献
7.
运用不含手性碳的非对称化合物S-BNP酸(S-phosphorsaeure-(1,1'-binaphthyl-2,2'-diylester))作反应试剂用快原子轰击反应质谱法(FAB-RMS)测定手性化合物的绝对构型.发现非对称手性化合物可与不对称手性化合物在质谱中发生立体选择性反应,S-BNP酸可作为一种新的反应试剂来测定手性化合物的绝对构型. 相似文献
8.
9.
高效液相色谱/氢化物发生/原子荧光快速检测尿砷形态 总被引:15,自引:0,他引:15
本文对砷形态分析方法进行了评述。提出了人尿中As(Ⅲ)、As(Ⅴ)、一甲基砷(MMA)和二甲基砷(DMA)的快速、灵敏的形态分析方法。方法基于在15cm长、3μm粒径的HPLC柱上快速分离不同形态的砷后以灵敏的氢化物发生/原子荧光检测。常见砷的四种形态的分析只须4min即可完成,检出限在μg/L级。标准样品尿中砷的形态分析结果与标准值吻合很好。本法已应用于摄取砷糖前、后所采集的尿样中砷的形态分析研 相似文献
10.
系统地研究了碱性条件下(pH8~10.8)As3+,As5+,MA,DMA和AB等砷化合物在PRP-X100阴离子交换柱上的保留行为。用火焰原子吸收光谱(FAAS)测定从HPLC分离的砷化合物,即通过一根1m×0.23mmi.d.不锈钢毛细管,将HPLC柱出口与FAAS的雾化器连接起来,采用乙炔/空气火焰,在193.7nm处测定。具体研究了两个流动相(20mmol/LNH4HCO3和2.5mmol/L对-羟基苯甲酸-1.0mmol/L苯甲酸水溶液),并系统研究了pH值和缓冲液浓度对上述5个砷化合物的保留时间的影响,发现对于20mmol/LNH4HCO3体系,在pH8.7时,AB,As3+,DMA可以得到完全分离,通过梯度洗提(pH8.7到9.8,流速1.65mL/min),在15min内上述5个砷化合物可以得到良好分离;对于2.5mmol/L对-羟基苯甲酸-1.0mmol/L苯甲酸体系,在pH9.0及流速1.5mL/min时,可以在12min内将上述5个砷化合物分离。 相似文献
11.
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
12.
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
13.
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
14.
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
15.
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
16.
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
17.
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
18.
19.
《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
20.
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