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 286 毫秒
1.
本文以四种阴离子缔合剂与苯海拉明形成的离子缔合物作电活性材料,制成了苯海拉明PVC电极,并就各阴离子缔合剂、介体溶剂以及膜相中活性物质的含量对电极性能的影响作了较详细的研究.确定以四苯硼酸作配合剂,邻苯二甲酸二丁酯作介体溶剂,取活性物质含量为0.5%时,电极性能较优.电极响应的线性区为1×10~-1-3.2×10~(-6)M,斜率可达60mv/△pc, pH范围为2.5-5.5.电极的抗干扰能力较强,响应快,重现性和稳定性好.初步应用表明,电极用于苯海拉明的样品分析是非常适宜的.  相似文献   

2.
离子选择性电极法测定药片中的奈福泮   总被引:1,自引:0,他引:1  
报道一种以奈福泮与苦酮酸形成的缔合物为电活性物的新型PVC膜奈福泮离子选择电极 ,电极的Nernst响应范围为 5 .0× 10 - 2 ~ 5 .0× 10 - 4 mol L ;斜率为 5 6mV pC ;检测限为 7.9× 10 - 5mol L .已将该电极应用于盐酸奈福泮药片中测定奈福泮的含量 ,结果与紫外分光光度法相符 .  相似文献   

3.
崔淑敏  宋美荣  李丹 《河南科学》2011,29(12):1440-1443
制备了一种以多西环素与四苯硼酸根形成的缔合物为电活性物质的聚氯乙烯(PVC)膜多西环素选择性电极,用直接电位法对多西环素制剂进行了测定.实验表明:该电极的Nernst响应范围为9.077×10-3~9.077 ×10-5 mol/L;Nernst响应斜率为49.24 mV/pc;该电极制备简单,选择性、重现性良好,用于...  相似文献   

4.
以2-氨基口白啶与SO2-4缔合物为电活性物质,以邻苯二甲酸二丁酯(DBP)为增塑剂,制作PVC膜硫酸根离子选择性电极.实验结果表明,电极对硫酸根离子具有良好的选择性和较高的灵敏度,其线性响应范围为5.0×10-7~1.0×10-1mol·L-1.用该电极测定水中的硫酸根离子含量,结果令人满意.  相似文献   

5.
以PVC为电极膜,二癸基磷酸钙为电活性物质,研究了钙离子选择性电极的制作方法.该电极在钙离子浓度10-1~10-5mol/L范围内电极电势符合Nernst方程,检出下限为10-6mol/L,适宜pH范围为4~9.在一定浓度范围内钙离子选择性电极可代替原子吸收光谱法和容量法进行土壤及水样品中钙含量测定,回收率87.7%~90.5%.  相似文献   

6.
以钴膜修饰碳纤维微电极为离子选择性电极建立了一种测定磷酸盐的新方法.利用该选择性微电极探讨测定磷酸盐的条件,并测定该电极的性能参数,在1.0×10-6~1.0×10-3mol·L-1范围,磷酸盐溶液浓度的对数与电位呈良好的线性关系和能斯特响应,检出限为6.0×10-7mol·L-1,并且该电极有良好的重现性、稳定性和选择性.  相似文献   

7.
以乙基紫为电活性物质的PVC膜IO_4~-电极的研制   总被引:1,自引:0,他引:1  
本文报道一种以乙基紫为电活性物质、邻苯二甲酸二丁醋(DBP)为增塑剂的PVC膜IO_4~-电极的研制方法。较佳的膜组成为乙基紫6mg,DBP0.4ml,PVC粉90mg。该电极对IO_4~-浓度在3.0×10~(-6)~1.0x10~(-1)mol/L范围内符合能斯特响应,其斜率为58.4mV/P_4~(IO-)(18℃)。  相似文献   

8.
PVC膜林可霉素药物电极的制作及应用   总被引:1,自引:0,他引:1  
以林可霉素与硝酸汞配合比为1:1的配位化合物作为电活性物质,研制了林可霉素-汞修饰PVC膜电极,并对影响其电化学性能的一些因素进行了探究,得到了良好的电极响应曲线,响应斜率为58.9mV/pC,线性范围达4个数量级,检出限为1.0×10-5mol/L,十多种常见无机离子与一些辅料对电极基本无干扰,可采用直接电位法测定市售注射液中的林可霉素主含量。  相似文献   

9.
采用循环伏安法制备了氢氧化铜/过氧化聚吡咯膜修饰电极(Cu(OH)2/PPyox/CCE),并对其进行了表征。研究了该修饰电极对Glu的电催化氧化活性。结果表明,该修饰电极对Glu的氧化具有良好的电催化活性。在优化条件下,安培法检测Glu的线性范围为2.0×10-7~1.2×10-3mol.L-1,灵敏度最高为2500.0μA.mmol-1.cm-2,检出限(3Sb)为1.0×10-7mol.L-1,加标回收率为96.5%~100.6%。该方法已用于血清中葡萄糖含量的测定。  相似文献   

10.
制备了以1,2-双(3-氨基苯氧基)乙烷为载体的聚氯乙烯(PVC)膜银离子选择电极,研究了电极膜中增塑剂种类及载体和离子定域体(KTpCIPB)含量对电极性能的影响.结果表明:此电极对Ag+具有很好的能斯特响应性能,在10(-6)~10(-3) mol/L的浓度范围内呈良好的线性关系,线性系数为0.9991,检测下限为8.5X10(-7)mol/L,响应斜率为59.9 mV/decade.电极对Ag+具有很好的选择性,碱金属、碱土金属及常见过渡金属离子对Ag+的测定干扰很小.该电极可在体积分数不大于30%的乙醇水溶液中使用,能准确滴定自来水中C1-的含量和维生素B6药片中维生素B6的含量,并用于实际样品中Ag+含量的直接测定.  相似文献   

11.
目的建立格拉司琼透皮贴剂的质量控制方法.方法采用高效液相色谱法测定贴剂中主药的含量、体外释放度,并以剥离强度、初黏力和持黏力为指标考察贴剂的黏附性.结果贴剂中格拉司琼的含量限度为(100±10)%;在2,6,10 h内的释放度分别为30%~35%、65%~75%和80%~85%;三批样品试验结果表明:该贴剂具有良好的黏附性.结论检测方法科学、合理,为格拉司琼透皮贴剂的质量控制提供了可靠依据.  相似文献   

12.
选取不同菌球形态的楸树内生真菌FSN002作为菌种进行发酵,对其菌球发酵液的抗癌活性进行测试,并采用高效液相色谱法对发酵液的成分进行初步分析.结果表明:所得发酵液中黄色物质由具有中等疏水性抗癌活性成分和其他杂质组成;具有周生菌毛的大菌球A可以产生黄色抗癌活性物质和无活性的黄色杂质,且其产量较高;而具有小头、长尾的乌贼状菌球D产生的活性抗癌成分较少,但所产生的黄色杂质也较少且纯度高,有利于后续活性抗癌成分的分离纯化.  相似文献   

13.
对阴离子表面活性剂化学传感器敏感膜的种类组成及其比例进行了筛选,确定了增塑剂为磷酸三甲酚酯,其质量分数为55%~75%;电活性物质为十六烷基三甲基溴化铵,其质量分数为0.6%~1%;聚合物基体为聚氯乙烯(PVC),其质量分数为24%~44.4%。实验结果表明,敏感膜机械强度好,其对阴离子表面活性剂的线性响应范围为1×10-7~1×10-3mol/L,阴离子表面活性剂浓度为1×10-3mol/L时,其响应时间为30 s。  相似文献   

14.
N Ling  S Y Ying  N Ueno  S Shimasaki  F Esch  M Hotta  R Guillemin 《Nature》1986,321(6072):779-782
Inhibin is a gonadal protein that specifically inhibits the secretion of pituitary follicle-stimulating hormone (FSH). Two forms of inhibin (A and B) have been purified from porcine follicular fluid and characterized as heterodimers of relative molecular mass (Mr) 32,000 (ref. 2). Each inhibin is comprised of an identical alpha-subunit of Mr 18,000 and a distinct but related beta-subunit of Mr 13,800-14,700 linked by interchain disulphide bond(s). Throughout the purification of inhibins, we consistently observed two fractions which stimulated the secretion of pituitary FSH. We report here the isolation of one of the FSH-releasing proteins; it has a Mr of 24,000 and its N-terminal sequences up to residue 32 are identical to those of each beta-subunit of inhibins A and B. In the presence of reducing agents, SDS-polyacrylamide gel electrophoresis resolves the FSH-releasing substance into two subunits which are identical in their migration behaviour to the reduced beta-subunits of inhibins A and B. Based on the N-terminal sequence data and Mr of the intact and reduced molecules, we propose that the FSH-releasing substance, which is active in picomolar concentrations, is a heterodimeric protein composed of the two beta-subunits of inhibins A and B linked by interchain disulphide bond(s). The structural organization of the FSH-releasing substance is homologous to that of transforming growth factor-beta (TGF-beta), which also possesses FSH-releasing activity in the same bioassay. We suggest that the substance be called activin to signify the fact that it has opposite biological effects to inhibin.  相似文献   

15.
测定了悬浮聚氯乙烯(S-PVC)树脂对增塑剂不同温度下的吸收量,采用扫描电镜表征了S-PVC不同增塑剂吸收条件下的结构形态.结果表明:S-PVC颗粒由多级粒子聚集而成,增塑剂主要通过各级粒子聚集体间的间隙沟槽进入PVC粒子内部完成润展与溶胀,S-PVC对增塑剂的吸收是具有时间和温度依赖性的四步吸收非定态过程.其吸收包括...  相似文献   

16.
Stimulation of connective tissue cell growth by substance P and substance K   总被引:25,自引:0,他引:25  
Connective tissue cells proliferate actively when cultured in the presence of serum. Platelet-derived growth factor (PDGF), a basic protein of relative molecular mass approximately 30,000, has been identified as the major serum mitogen for these cells; its main physiological/pathophysiological role may be to initiate wound healing in connection with tissue injury. However, growth of cultured cells is also influenced by several other factors, including epidermal growth factor, fibroblast growth factor, insulin and somatomedins. Furthermore, Rozengurt and Sinnett-Smith recently showed that bombesin, a neuroendocrine peptide isolated from frog skin, stimulates DNA synthesis and cell division in cultures of a specific subtype of 3T3 cells. Substance P and substance K (also known as neurokinin A or neuromedin L) are mammalian peptides belonging to the tachykinin family. Substance P has been studied extensively; it is distributed widely throughout the central and peripheral nervous system, including primary sensory neurones, and can be released in the periphery from axon collaterals of stimulated pain fibres and contribute to the inflammatory response. Substance K is a member of the tachykinin family isolated from mammalian spinal cord; Nawa et al. determined the primary structure of two types of substance P precursors, one of which contained a sequence homologous to substance K, as well as the sequence of substance P. We report here that substance P and substance K stimulate DNA synthesis in cultured arterial smooth muscle cells and human skin fibroblasts, and that this stimulation is inhibited by the substance P-antagonist spantide.  相似文献   

17.
选择四种具有不同互溶度的液液体系,研究表面活性剂的加入对单液滴传质系数的影响。结合界面张力的测定结果,探讨互溶度、界面活性与传质系数的关系。结果表明,互溶度与界面活性、传质系数的降低之间存在着对应关系,对于低界面张力、部分互溶的体系,界面张力不是决定表面活性物质对液滴传质系数影响程度的主要因素。  相似文献   

18.
碳酸铵法制备活性氧化锌   总被引:4,自引:0,他引:4  
研究了用菱锌矿一次精选后矿粉,经硫酸酸溶、过滤后,利用氧化法及置换法除去杂质;用廉价的碳酸铵制备成碱式碳酸锌,经过滤、烘干、煅烧,最后得到活性氧化锌的生产工艺。  相似文献   

19.
S D Brain  T J Williams 《Nature》1988,335(6185):73-75
The 37-amino-acid calcitonin gene-related peptide (CGRP) occurs as a result of alternative processing of mRNA from the calcitonin gene. The potency of CGRP as a vasodilator and the occurrence of the peptide in nerves associated with blood vessels suggest an important role for CGRP in the regulation of blood flow. The finding that CGRP induces protracted vasodilatation when administered extra-vascularly, to mimic release from nerves, has led us to investigate how the vasodilator activity of CGRP is controlled in vivo. CGRP is often co-localized with substance P in C-fibre nerves. Here, we demonstrate that injection of CGRP with substance P into human skin converts the long-lasting vasodilatation induced by CGRP into a transient response. Experiments in animals reveal that the phenomenon is dependent on the action of proteases from mast cells stimulated by substance P. The results reveal a new regulatory interaction between two neuropeptides and provide evidence for an in vivo role for mast cell proteases.  相似文献   

20.
为提高用作高能电池阳极活性物质AgO的稳定性,本文选用有机试剂二氧六环对AgO颗粒进行表面处理。处理后的AgO分解百分率由13.42%降到6.96%。与日本公开专利用四氢呋喃处理的AgO相比,稳定性也进一步提高,四氢呋喃处理的AsO分解百分率为8.03%。由此可见,用二氧六环处理的AgO更适合作高能电池的阳极活性物质。  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