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1.
报告了测定痕量铜的一种新方法。在0.01mol/LHAc-NaAc溶液中,铜和乙醛酸缩氨基硫脲(GATSC)形成的配合物产生一很灵敏的还原峰,峰电位是-0.33V(vs·SCE),铜的浓度在1.0×10-8~2.0×10-6mol/L范围内成直线关系,检测限为3.0×10-9mol/L,该法用于测定水中痕量铜,结果令人满意。  相似文献   

2.
2.5次微分溶出伏安法测定茶叶中痕量锌   总被引:4,自引:0,他引:4  
本报告了测定痕量锌的一种新方法,在0.01mol/LHAc-0.01mol/LNaAc溶液中,锌和乙醛酸缩氨基硫脲形成的配合物产生一个很灵敏的还原峰,峰电位是一-0.82V(vs.SCE),锌的浓度在2.0×10^-8-8.0×10^-7mol/L范围内与峰高呈直线关系,检测限是6.0×10^-9mol/L,该方法用于测定茶叶中痕量锌,结果令人满意。  相似文献   

3.
亚硝酸根—巯基乙酸—钴(Ⅱ)络合物的极谱吸附波研究   总被引:7,自引:0,他引:7  
魏显有 《分析化学》1998,26(5):548-551
提出了一个测定痕量亚硝酸根的极谱吸附波新体系.在含有巯基乙酸(TGA)和钻.(Ⅱ)的 pH 4.4的 H2SO4-NaAc介质中,得到一灵敏的亚硝酸根络合物单扫极谱吸附波,峰电位为-0.75 V(vs.SCE).峰电位与亚硝酸根浓度在1.1× 10-3-8.7×10-6mol/L范围内呈线性关系.检出限为 5. 5×10-9 mol/L.本法简便快速,选择性好,用于水样和食品中痕量NO-2的测定,结果满意。  相似文献   

4.
报道了测定痕量镍的一种新方法.在NH3·H2O-NH4Cl-安息香缩氨基硫脲体系中,镍产生一灵敏的还原波,该波的峰电位是-0.75V(vs·SCE),镍的浓度在1.0×10-8~8.0×10-7mol/L范围内与峰高成直线关系,检测限是3.0×10-9mol/L,该法用于测定水中痕量镍,结果令人满意.  相似文献   

5.
在0.01mol/LNH.H2O-NH4Cl和3.0×10^-5mol/L安息香缩氨基硫脲体系中,钴产生一灵敏的还原波,其峰电位是-0.94V(vs.SCE),峰电流与钴的浓度在2.0×10-8-1.0×10^-6mol/L范围内成直线关系,检测限为5.0×10^-9mol/L,该法测定水中痕量钴结果令人满意。  相似文献   

6.
在pH4.0的HAc-NaAc缓冲介质中,Sn(Ⅱ)与1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(PMBP)生成络合物,于-0.74V(vs.SCE)出现一灵敏的极谱峰。锡含量在4.2×10-8mol/L~3.4×10-6mol/L范围内与峰高呈线性关系,检出限为1.7×10-8mol/L。用多种电化学方法研究了极谱波的性质及电极反应机理,证明该极谱波为络合吸附波,峰电流由中心离子Sn(Ⅱ)还原产生,络合物组成为Sn(Ⅱ)∶PMBP=1∶1。试验了多种离子对峰电流的影响。方法已用于矿样中痕量锡的测定。  相似文献   

7.
锗(Ⅳ)-邻苯二酚紫-钒(Ⅳ)体系的极谱吸附催化波研究   总被引:5,自引:0,他引:5  
在0.1mol/LH2SO4溶液中,Ge(Ⅳ)-邻苯二酚紫(PV)-V(Ⅳ)体系产生一灵敏的吸附催化波,峰电位在-0.55V(vs.SCE)处.锗浓度在2.2×10-10~2.8×10-6mol/L范围内与峰电流呈线性关系.检出限为1.1×10-10mol/L.研究了极谱波的性质.本法用于土壤中痕量锗的测定,结果满意.  相似文献   

8.
镓(Ⅲ)-向红菲咯啉络合物极谱吸附波的研究及应用   总被引:2,自引:0,他引:2  
李秀玲  周长利  卢燕  曹伟  杨锋 《分析化学》1998,26(4):451-453
在 PH=4.2的 0.07 mol/L HAc-NaAc介质中,Ga(Ⅲ)-向红菲咯啉络合物在单扫描极谱仪上于-0.98 V(vs.SCE)处产生一灵敏的吸附还原波,其二阶导数波灵敏度高,波形好,峰电流 Ip与 Ga(Ⅲ)在 8.0×10-8~3.0× 10-6mol/L的浓度范围内呈现良好线性关系,检出限为7.0×10-8mol/LGa(Ⅲ)。用该法对粮食中的镓进行了测定,并对电极过程进行了研究。  相似文献   

9.
在pH5.1的HCl-六次甲基四胺缓冲溶液中,Cd(Ⅱ)-β-巯基丙酸配合物产生-灵敏的极谱吸附波.峰电流在-0.67V(vs.SCE)左右,峰高与镉浓度在1.8×10-9~3.6×10-6mol/L范围内呈线性关系.检出限为9×10-10mol/L.研究了极谱波的性质和电极过程机理.本法用于食品中痕量镉的测定,结果满意  相似文献   

10.
镉(II)—β—巯基丙酸配合物极谱吸附波研究   总被引:1,自引:0,他引:1  
在pH5.1的HCl-六次甲基四胺缓冲溶液中,Cd(Ⅱ)-β-巯基丙酸配合物产生-灵敏的极谱吸附波。峰电流在-0。67V(vs.SCE)左右,峰高与镉浓度在1.8×10^-9 ̄3.6×10^-6mol/L范围内呈线性关系。检出限为9×10^-10mol/L。研究了极谱波的性质和电极过程机理。本法用于食品中痕量镉的测定,结果满意。  相似文献   

11.
利用手持技术改进测定乙醇分子结构实验   总被引:1,自引:0,他引:1  
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。  相似文献   

12.
13.
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.  相似文献   

14.
实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。  相似文献   

15.
16.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

17.
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.  相似文献   

18.
由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。  相似文献   

19.
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.  相似文献   

20.
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.  相似文献   

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