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 11 毫秒
1.
青少年全血微量元素正常值探讨   总被引:9,自引:0,他引:9  
由于国内尚无青少年全血铜、锌、铁、钙含量的正常值标准,为探讨其正常值范围,根据广州地区193名中学生全血铜、锌、铁、钙含量的测定结果,初步提出了广州地区13至18岁青少年全血铜、锌、铁、钙含量的正常值范围。结果表明,广州地区13至18岁青少年血铜含量均值为0.77bμg/g。正常值0.52~1.02μg/g;锌含量:13~岁均值5.22μg/g,正常值〉3.93μg/g;15~岁均值为5.54μg/g,正常值〉4.40μg/g;17~岁均值为5.68μg/g,正常值〉5.06μg/g;铁含量均值为500.00μg/g,正常值363.00~637.00μg/g;钙含量均值为78.70μg/g,正常值〉53.00μg/g。提示青少年除锌含量有必要按年龄组确定正常值范围之外,血铜、铁、钙含量的正常值范围可不按年龄和性别划分,均可合并计算。  相似文献   

2.
依来络兰黑R褪色光度法测定痕量铜   总被引:1,自引:0,他引:1  
在氨水介质中,微量铜可催化亚硝酸钠氧化依来络兰黑R褪色,由此建立了一种高灵敏度光度法测定微量铜的方法。间接摩尔吸光系数ε530=2.5×106L·mol-1·cm-1,线性范围为0~8μg/25ml,线性回归方程△A=0.0123C+0.0076,r=0.9994,方法用于环境废水中微量铜的测定,选择性好,灵敏度高,结果满意。  相似文献   

3.
单扫描示波极谱法连测五味子、榛蘑中的铜和锌   总被引:1,自引:0,他引:1  
研究了在HCl-KSCN底液中用单扫描示波极谱法连续测定五味子、榛蘑中铜和锌的方法。在此底液中,铜、锌分别在-0.42V(vs.SCE)、-1.03V(vs.SCE)处产生一敏锐的二阶导数波,检出限分别为0.005、0.01μg/mL,线性范围分别为0.01~8.00μg/mL,0.01~10.00μg/mL。应用本方法测定了五味子、榛蘑中的铜和锌,方法回收率为96.5%~101.8%。  相似文献   

4.
研究了香蕉中的金属元素的含量和火焰原子吸收光谱法在同一体系中测定香蕉中微量元素铜、铁、锌、锰的方法,考察了硝酸、过氧化氢的不同用量以及消化时间长短的影响和在同一体系中铜、铁、锌、锰的相互干扰情况。在选定条件下铜检测限为0.064μg/mL,铁为0.275μg/mL,锌为0.157μg/mL,锰为0.187μg/mL,相对标准偏差为1.9%-4.7%,回收率为92.3%-105.0%。  相似文献   

5.
合成了新荧光试剂2,3,4-三羟基苯乙酮缩-2-羧基苯胺(TAFA)。详细研究了试剂与铜的荧光反应新体系的最佳适宜条件。在pH9.0的乙醇/水(3.5:6.5,V/V)溶液中,该试剂与铜离子形成稳定的络合物,组成比为1:1(金属:试剂),λex/em=422.4/561.6nm。所建立的铜的荧光分析方法的线性范围为0.5~120.0μg/L;检出限为0.26μg/L。方法成功地应用于矿泉水和水中痕量铜的测定。  相似文献   

6.
病人经各项检查均未查出致畸原因。但查微量元素后发现铜(Cu)和锌(Zn)均低于正常值,经补充铜和锌后,均生健康婴儿。血清铜正常值为0.80—1.20μg/mL,血清锌正常值为0.70~1.20μg/mL。  相似文献   

7.
壳聚糖富集火焰原子吸收法测定水中痕量铜   总被引:8,自引:2,他引:8  
王瑜 《分析化学》2005,33(6):872-874
采用壳聚糖修饰钨丝基质螺旋卷,直接浸入含有痕量铜的pH5.0的Brltton-Robinson缓冲溶液中,经电磁搅拌富集一定时间后,将其转移至空气/乙炔火焰燃烧器上,利用火焰原子吸收光谱法简便快速测定水中痕量铜。方法的线性范围为2—75μg/L;检出限为0.98μg/L。同一支钨丝螺旋卷重复涂敷壳聚糖富集Cu,RSD(n=6)为2.7%。  相似文献   

8.
采用自制的聚氯乙烯多乙烯多胺(PVC-PP)树脂,在pH值为5.0的条件下,分离富集海水中的痕量铜、镍、钴,以1.2mol/L盐酸溶液洗脱.火焰原子吸收光潜法测定,富集倍数最大可达100倍(回收率大于90%)。研究了吸附与洗脱的最佳条件,方法检出限分别为铜0.81μg/L、镍0.98μg/L、钴0.57μg/L(富集倍数100,S/N=3),相对标准偏差小于5%(n=7),样品加标回收率在90%-105%之间。  相似文献   

9.
侯明  张静 《分析科学学报》2004,20(6):619-621
在λex/λem=404.7/550nm,乳化剂OP存在下,荧光红-曙红Y能够发生有效能量转移,使曙红Y荧光强度大大提高;在pH6.5~7.6的KH2PO4-NaOH缓冲溶液中,Cu(Ⅱ)与曙红Y和邻菲罗啉形成配合物,使曙红Y的荧光猝灭,从而建立了测定痕量铜的荧光分析新方法。铜含量在0~250μg/L范围内与曙红Y的荧光猝灭程度呈良好的线性关系。方法的检出限为0.82μg/L;测定100μg/L铜溶液,其RSD为4.6%(n=11);样品加标回收率为102.1%~105%。本法用于人发、茶叶和大米中痕量铜的测定,结果满意。  相似文献   

10.
DNA荧光探针—荧光素-中性红体系的研究   总被引:5,自引:0,他引:5  
基于DNA对荧光素(FL)-中性红(NR)分子间荧光能量转移的抑制作用,以荧光素-中性红为荧光探针,考察该探针与DNA的结合反应,建立了准确测定DNA的新方法,在pH=6.5条件下,hsDNA、ctDNA和smDNA的浓度与荧光素-中性红体系的荧光比值变化量Δ(Fd/Fa)成线性关系,响应线性范围分别为0.25-6.25μg/mL、0.10-5.00μg/mL、0.10-4.00μg/mL,0.025μg/mL和0.023μg/mL;分析测定了DNA合成样品,回收率91.3%-101.4%,相对标准偏差小于4.2%.  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.
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   

13.
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   

14.
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   

15.
16.
《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   

17.
Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.  相似文献   

18.
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.  相似文献   

19.
A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).  相似文献   

20.
Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO4 oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.  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