首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 57 毫秒
1.
顶空气相色谱法测定血清中微量碘   总被引:8,自引:0,他引:8  
符展明  葛庆成 《分析化学》1996,24(2):198-201
根据碘离子与硫酸二甲催化反应生成挥发性的碘甲烷,应用顶空GC法测定血清中的微量碘,回收率为88.26%~95.72%,相对标准偏差为0.72%~2.2%。  相似文献   

2.
邓传跃  陈旭东 《分析化学》1996,24(2):168-171
本文以反相高效液相色谱法(RP-HPLC)研究了铁-芳烃络合物光引发剂及光解产物的分离条件和影响因素,推导出光解动力学方程式,方法灵敏度高,引发剂的检测限为100ng/L,测定的标准偏差为0.31%~0.46%,相对标准偏差为0.82%~2.13%,在此条件下样品杂质不干扰测定。  相似文献   

3.
协同催化光度法测定血清中唾液酸   总被引:5,自引:0,他引:5  
本文利用Cu^2+和Cr^3+的协同催化作用及Brij35的增溶作用建立了测定唾液酸的光度分析新方法,该方法的线性范围为0~980mg/L,检出限为1.5mg/L,相对标准偏差为1.83%~2.66%,回收率为94.7%~102.0%,用于测定人血清中的唾液酸,获得满意结果。  相似文献   

4.
本文报道空气中氯氰菊酯的高效液相色谱测定方法,空气样品用硅胶管采样,经甲醇洗脱后用HyporsilODS柱分离,紫外检测器检测,在本法的测定条件下,最低检测浓度为0.04mg/m^3,当氯氰菊酯浓度范围为0~25.0mg/L时,呈线性响应关系,相对标准偏差为2.4%~8.4%,本法的解吸效率为96.8%~100.3%,采样效率为100%,氯氰菊酯在硅胶管中可稳定7d。  相似文献   

5.
本文介绍了石墨炉原子吸收光谱法测定天然饮用矿泉水中的钼。水样不需浓缩萃取直接测定。线性范围0.02~1.6ng,检测限0.01ng,相对标准偏差2.3%-4.5%,回收率96%-103%。  相似文献   

6.
荧光光度法测定愈风宁心片中葛根素含量的研究   总被引:7,自引:0,他引:7  
本文研究了葛根素的荧光测定法及其实验条件,其最大激发波长和荧光波长分别为258.6nm和477.0nm。该方法线性范围0~6.0μg·mL—1,可用于愈风宁心片中葛根素含量测定,回收率在93.1%~109.2%,相对标准偏差<2%(n=3)。  相似文献   

7.
碘的凝胶色谱测定方法   总被引:6,自引:1,他引:6  
丁朝武  李华斌 《分析化学》1997,25(5):586-589
建立了碘折凝胶色谱测定方法。色谱条件为:Shim-pack DIOL-150柱;流动相甲醇0.01mol/L H3PO4(10:90)流速为1.2mL/min;柱温为35℃,检测波长为224nm;线性范围是0.010-1.0mg/L,相关系数为0.9993,检测限为0.001mg/L,相对标准偏差为1.2%-4.6%;回收率为91%-98%。所建立的方法已用于食盐,尿,系带等样品的测试,均取得较好  相似文献   

8.
氢化物-原子吸收光谱法测定六味地黄丸中砷和锑   总被引:1,自引:0,他引:1  
本文建立了氢化物原子吸收光谱法测定六味地黄丸中砷和锑的方法。方法的相对标准偏差砷为1.3%、锑为1.6%,回收率在90%~110%之间,检出限分别为砷0.06ng/mL、锑0.1ng/mL。本方法可用于中成药中砷和锑的测定。  相似文献   

9.
铜的催化动力学电位法测定   总被引:4,自引:0,他引:4  
本文报道了利用碘离子选择电极监测H2O2-KI氧化还原反应体系被Cu(Ⅱ)催化的反应速度,建立了测定Cu(Ⅱ)的催化动力学方法,其线性范围为10-80ng/mL,该法用于铝合金标样中铜的测定,结果非常接近标准样品的标准值,相对标准偏差为0.36%,回收率在98.3%-105.6%之间。  相似文献   

10.
本文研究了快速、简便测定蜂皇浆及制品中添加的低含量维生素B_6的HPLC法。称取适量样品,用10%偏磷酸提取、净化,清液供HPLC分析用。WATERS荧光检测器,激发波长290nm,发射波长390nm,VB_6含量在0~120ng之间工作曲线相关系数大于0.999,样品中VB_6含量为0.1%~5%时,方法回收率为92.17%~98.42%,相对标准偏差(n=6)小于3.7%。  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.
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   

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.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号