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1.
文冠木为常用蒙药材之一。本实验采用微波消解-原子发射光谱法测定测定蒙药文冠木中Cd 、Zn 、Mn 、Fe 、Mg 、Cu 、 Hg等 16种元素。在选定的实验条件下,测定方法的加样回收率为90.9% ~109%,相对标准偏差均小于3.51%,检出限小于0.0051mg﹒mL-1。该方法简便、准确、可靠,可作为文冠木中多种元素含量的测定方法。  相似文献   

2.
《广州化学》2016,(1):10-14
建立了醋酸酯淀粉中7种元素含量微波消解-电感耦合等离子体质谱(ICP-MS)测定方法。通过比较干法、湿法、微波消解三种醋酸酯淀粉前处理方法,选用耗时短、回收率高、操作稳定的微波消解法对醋酸酯淀粉进行消解,利用ICP-MS法测定硼、铝、铬、镍、砷、镉、铅7种元素含量。该方法线性范围广,线性相关系数r0.999 7,回收率92.0%~100.3%,RSD3.8%。具有操作简单、快速、准确、可靠等优点,在醋酸酯淀粉分析中,取得了令人满意的结果。检测结果表明,醋酸酯淀粉中铝含量在4 mg/kg~7 mg/kg,其余元素均小于0.2 mg/kg。  相似文献   

3.
建立了化妆品中铍、铬、砷、镉、碲、钕、铊、铅8种有害元素的测定方法,样品采用微波消解,以钇、锂、铟、铋为测定的内标元素,用电感耦合等离子体质谱法测定,结果表明,各元素和内标元素在一定浓度范围内的质量数比值均与浓度呈良好的线性关系,线性方程的相关系数均大于0.999 8,平均加标回收率为95%~104%,相对标准偏差(RSD)均小于3%。方法灵敏度高,准确,可为化妆品中上述元素的限量检查提供参考。  相似文献   

4.
建立了化妆品中铍、铬、砷、镉、碲、钕、铊、铅8种有害元素的测定方法,样品采用微波消解,以钇、锂、铟、铋为测定的内标元素,用电感耦合等离子体质谱法测定,结果表明,各元素和内标元素在一定浓度范围内的质量数比值均与浓度呈良好的线性关系,线性方程的相关系数均大于0.999 8,平均加标回收率为95%~104%,相对标准偏差(RSD)均小于3%。方法灵敏度高,准确,可为化妆品中上述元素的限量检查提供参考。  相似文献   

5.
目的:建立化妆品中铍、镉、铊、铬、砷、碲、钕、铅8种有害元素的测定方法。方法:采用电感耦合等离子体质谱法,样品采用微波消解,以钇、锂、铟、铋为内标作定量分析。结果:各元素和内标元素在一定浓度范围内的质量数比值均与浓度呈良好的线性关系,线性方程的相关系数均大于0.9998,平均回收率为95%~104%,相对标准偏差(RSD)均小于3%。结论:该方法灵敏度高,准确,可为化妆品中上述元素的限量检查提供参考。  相似文献   

6.
目的采用合适的样品前处理方法和电感耦合等离子原子发射光谱仪(ICP-AES)测定牙膏中铅、铜和锌。方法选择微波消解法、酸湿式消解法和干式消解法对样品进行前处理,对比这几种方法的结果。优化仪器测定参数以适应此类样品测定。测定方法的线性范围、相关系数、检出限、精密度、加标回收率等,探讨了相关结果的影响因素。并且与原子吸收比对。结果本法采用线性范围为0~2.000 mg/L,样品测定6次,所有元素相对标准偏差小于2.56%,加标回收率在95.95%~104.53%之间。结论用ICP-AES同时测定牙膏铅、铜和锌3种元素,具有良好的准确度和精密度,灵敏度高、检出限低、线性范围宽、元素之间的干扰少,样品前处理采用微波消解法,是高效可行的方法。  相似文献   

7.
研究了植物样品中非金属元素硫、磷的测定方法,采用微波消解处理样品,ICP-AES测定大米、小麦、玉米、黄豆、圆白菜、菠菜、茶叶等植物样品中的硫、磷,加标回收率为95.2%~105%,相对标准偏差小于5.0%。  相似文献   

8.
利用硝酸、盐酸、氢氟酸混合液和微波消解仪密闭消解样品,建立了一种微波消解-电感耦合等离子体质谱(ICP-MS)法同时测定土壤中铜、铅、锌、锰、钒、铬、镉、镍、锡、铊10种重金属的分析方法。取0.100 0 g土壤样品于消解罐中,采用4 mL硝酸+1 mL盐酸+1 mL氢氟酸消解体系按照设定程序进行微波消解,冷却,定容后利用电感耦合等离子体质谱法进行。结果表明,以铑元素作为内标,10种重金属元素在一定的质量浓度范围内与其信号强度呈线性关系,线性相关系数均不小于0.999 8,检出限为0.010~0.92 mg/kg。对3种标准物质进行测定,测定值的相对标准偏差为2.89%~7.72%(n=10),相对偏差为-5.95%~4.11%。该方法分析流程简单,工作效率高,检出限低,适合大批量土壤样品的多元素同时分析。  相似文献   

9.
本文提出硅石消解新技术--微波消解法.于聚氯乙烯消解罐中加硝酸、氢氟酸、高氯酸,程序加压升温分解硅石.微波消解法与冰浴法、加热消解法相比,可避免待测元素在分解过程带来的损失,且分解完全,酸用量少,操作简单、可靠.硅石经微波消解后采用火焰原子吸收光谱法检测铁、锰、镁、钙,铁、锰、镁、钙的回收率分别为97.3%~99.0%、104.4%~106.5%、95.7%~98.0%、103.1%~106.6%,与国家标准方法分析结果比较,相对误差均小于5%.  相似文献   

10.
建立了微波消解-电感耦合等离子体质谱(ICP-MS)法测定酒石酸氢可酮原料药中痕量元素钯含量的方法。样品经过微波消解,在优化ICP-MS仪器工作参数后,对样品中的钯含量进行测定。结果表明,方法检出限为0.002 9μg/mL,加标回收率在94.90%~103.4%,相对标准偏差小于3%。方法实现了对化学原料药中痕量钯的快速、简便、准确的检测。方法有望用于其它类似化学原料药中多种痕量元素的同时检测。  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.
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   

13.
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   

14.
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   

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.
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   

17.
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   

18.
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   

19.
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   

20.
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   

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