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 共查询到20条相似文献,搜索用时 46 毫秒
1.
金同顺  贝源 《分析化学》1996,24(3):360-363
研究了一种小型同心氢化物发生配置一个气液分离器后与多道ICP-AES联用,同时测定水和生物样品中砷、铋、锑、硒的方法。检出限为砷0.4μg/L,铋0.5μg/L,锑1.4μg/L,硒0.5μg/L,相对标准偏差为砷2.7%,铋1.5%,锑2.7%,硒1.9%。用本法测定美国和国家标准物质中的氢化元素,结果满意。  相似文献   

2.
氢化物-原子荧光法测定排污河水中砷   总被引:18,自引:1,他引:17  
采用氢化物-原子荧光法测定排污河水中砷,讨论并确定了试验的最佳测定条件,结果表明,方法的检出限为0.10μg.L^-1,相对标准偏差为3.5%,回收率为90%~110%。  相似文献   

3.
聚铝共沉淀氢化物发生(HG)—ICP—AES法测定痕量砷   总被引:1,自引:1,他引:0  
采用孔雀绿与砷钼酸盐形成离子对,以聚铝作为共沉淀剂富集分离,HG-ICP-AES法测定痕量砷的新方法。对离子对化合物的形成,聚铝共沉淀及氢化物发生条件进行了试验及优化。实验结果表明,显著改善了测定As的灵敏度和选择性。当富集倍数为20时,方法的检出限达0.09μg/L。  相似文献   

4.
聚铝共沉淀氢化物发生(HG)-ICP-AES法测定痕量砷   总被引:1,自引:0,他引:1  
采用孔雀绿与砷钼酸盐形成离子对,以聚铝作为共沉淀剂富集分离,HG-ICP-AES法测定痕量砷的新方法。对离子对化合物的形成,聚铝共沉淀及氢化物发生条件进行了试验及优化。实验结果表明,显著改善了测定As的灵敏度与选择性。当富集倍数为20时,方法的检出限达0.09μg/L。本法已用于天然水和湖底沉积物标样(NIES,P.S.)中痕量As的测定。  相似文献   

5.
原子荧光光谱法测定城市污水中的铅   总被引:5,自引:3,他引:2  
研究了用氢化物原子荧光法测定城市污水中铅的方法。对样品前处理方法进行了筛选,在选定的最佳实验条件下,方法检出限为0.55μg/L。标样含量在25μg/L时,其变异系数为0.3%。以实际样品测定,加标回收率为96%-101%,变异系数在2%以内,证明本方法测定污水中的铅切实、有效。  相似文献   

6.
焙烧富集分离—氢化物原子荧光法测定地质物料中痕量硒   总被引:3,自引:1,他引:2  
任萍  张勤 《分析试验室》1994,13(4):65-67
本文研究了一种焙烧富集分离,氢化物-原子荧光法测定地质物料中痕量Se方法。系统地了Se富集分离条件,考查了30多种元素在焙烧前后对测定Se的影响。在选定的最佳实验条件下,方法检出下限为0.01μg/g和0.089μg/g,线性范围0.001-0.3μg/mL。样品中Se含量水平为0.036μg/g和0.089μg/g时的测量精度(RSD)分别为10%和5.8%。加标回收率为97-99%。采用本方法  相似文献   

7.
焙烧富集分离-氢化物原子荧光法测定地质物料中痕量硒   总被引:5,自引:0,他引:5  
本文研究了一种焙烧富集分离、氢化物-原子荧光法测定地质物料中痕量Se的方法。系统地研究了Se富集分离条件、考查了30多种元素在焙烧前后对测定Se的影响,在选定的最佳实验条件下,方法检出下限为0.01μg/g,线性范围为0.001~0.3μg/mL。样品中Se含量水平为0.036μg/g和0.089μg/g时的测量精度(RSD)分别为10%和5.8%。加标回收率为97~99%。采用本方法分析了26个地球化学标准参考样中痕量硒,获得满意结果。  相似文献   

8.
流动注射荧光法测定磷,砷,硅   总被引:5,自引:0,他引:5  
宋功武 《分析化学》1997,25(12):1404-1406
研究了流动注射荧光法同时测定磷,砷,硅。确定了最佳反应条件。最大发射光波长555nm。磷,硅在0-80μg/L,砷在0-100μg/L范围内有良好的线性关系。  相似文献   

9.
本文提出用简易氢化物发生系统与ICP光谱仪联用,测定自来水和矿泉水中痕量砷的简易、快速的方法。用氢氧化铁共沉淀水中痕量砷,沉淀用离心机分离和富集。选择最优化的反应条件和工作条件。方法的检测限为0.002μg/L,精密度为2%,回收率在90%~104%之间。  相似文献   

10.
氢化物发生—ICP发射光谱光测定饮用水中痕量砷   总被引:1,自引:0,他引:1  
本文提出用简单氢化物发生系统与ICP光谱仪联用,测定自来水和矿泉水中痕量砷的简易、快速的方法。用氢氧化铁共沉淀水中痕量砷,沉淀用离心机分离和富集。选择最优化的反应条件和工作条件,方法的检测限为0.002μg/L,精密度为2%,回收率在90%~104%之间。  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

15.
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   

16.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

17.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

18.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
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   

20.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

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