催化极谱法测定锌电解液中微量钴

在湿法炼锌厂 ,锌电解液中杂质钴对析出锌的质量和锌电解的电流效率影响较大。传统工艺用黄药净化除钴 ,对钴的测定要求是 1μg· ml-1,通常采用亚硝基 - R盐比色法测定。自采用锑盐深度净化工艺后 ,对钴的测定要求为 0 .1 μg· ml-1,亚硝基 - R盐比色法的灵敏度达不到这个要求。本文在文献 [1 ,2 ]基础上采用催化极谱法测定钴 ,在柠檬酸铵 -盐酸羟胺底液中 ,Co( )与丁二酮肟形成的络合物在示波极谱仪上产生波形良好的催化极谱波 ,波峰电位为 - 1 .1 V(vs.SCE)。Zn2 +在此底液中的还原极谱波的波峰电位为 - 1 .3V,严重影响 Co2 +的催化…     

示波极谱法测定皮蛋中微量铅

在 pH 5 .2～ 5 .8的六次甲基四胺 HCl底液中 ,Pb2 +与邻菲啉 (phen)共存体系于- 0 .4 9V(vs .SCE)处产生一灵敏的极谱吸附波 ;铅浓度在 0 .0 15～ 0 .8μg·ml- 1范围内与峰电流呈良好线性关系 ,检出限可达 0 .0 0 8μg·ml- 1,线性回归方程为Iy=6 .80 + 12 4 .0 0Cx,相关系数为0 9973。用该方法测定了皮蛋中微量铅 ,试样加标回收率为 96 %～ 10 4 % ,相对标准偏差小于2 5 % ,结果与原子吸收吸光光度法一致。该方法准确、简便、选择性好。     

纯铝中微量钴镍的极谱测定

钴、镍在丁二酮肟 氯化铵 氨 亚硝酸钠体系中能产生极其灵敏的极谱催化波。镍峰电位为 - 0 .98V ,钴峰电位为 - 1.18V(vs .SCE)。钴、镍的线性范围分别为 1.2× 10 -4 ～ 6.0× 10 -2 μg·ml-1,2 .0× 10 -3～ 2 .0× 10 -1μg·ml-1,检出限分别为 3× 10 -11% ,3.3× 10 -10 %。用于测定纯铝样品中微量的钴、镍 ,重现性好 ,结果满意     

钴（Ⅲ）—亚硝基R盐体系极谱波研究及锌电解液中钴的快速测定

提出了一个测定微量钴 (Ⅱ )的极谱吸附波新体系。在pH 9.5的柠檬酸铵底液中 ,钴(Ⅲ ) NRS络合物在 - 0 .5 7V(vs .SCE)有一良好的吸附波 ,二阶导数波峰电流与钴浓度在 0 .0 1～1.2 μg·ml- 1范围内呈线性关系 ,检出限为 5ng·ml- 1。研究了极谱波性质和形成机理 ,应用于锌电解液中微量钴的分析 ,简便快速 ,结果准确     

催化动力学交流示波极谱法测定微量钒的研究

研究了在柠檬酸-柠檬酸钠缓冲溶液中,V(Ⅴ)催化过氧化氢氧化茜素红S的褪色反应A其动力学条件,建立了一种高灵敏度、高选择性测量微量V(Ⅴ)的新方法。测定V(Ⅴ)的线性范围为1．0～6．0μg·ml-1,检出限为0．50μg·ml-1,有色溶液及沉淀不干扰测定,优于催化光度法,使得用于常量分析的交流示波极谱法可以进行微量测定。方法用于合金钢中钒的测定,结果满意。     

单扫描极谱法测定罐装水果中微量锡

建立了一种简易、快速检测罐装水果中锡的单扫描极谱法.在 0. 05mol·L-1H2C2O4和 0. 003 %次甲基绿体系中,Sn(Ⅳ)在汞电极上于-0. 52V(vs.SCE)处有一灵敏的极谱波.该极谱波的波高与Sn(Ⅳ )的浓度在3. 0×10-8 ~ 5. 0×10-6 g·mL-1范围内呈线性关系,检测下限为 8. 2×10-9 g·mL-1,应用该法测定了罐装水果中的微量锡,并同光度法所获结果进行了对照,结果基本一致.     

半微分极谱法连续测定食物中锌铁锰和铜

研完了用1.5次微分极谱法,在乙二胺-8-羟基喹咻系列底液中,连续测定食物中锌、铁、锰和铜的方法。在选定的试验条件下．锌、铁和锰的浓度在0.02～4.0μg·ml-1、的浓度在0.02～1.0μg·ml-1范围内与峰高呈线性关系。样品测定的相对标准偏差为4.7%～10.0%,回收率为92.5%～106.0%。对食物样品分析的结果与电感耦合高频等离子体发射光谱法(ICP)比较,没有显著性差异。     

示波极谱法测定生物样中铜

水杨基荧光酮(SAF)在吸光光度分析中应用较广,而在极谱分析中应用很少。我们发现在柠檬酸盐介质中、Cu(Ⅱ)与SAF生成络合物并产生灵敏的极谱电流,峰电位—0.30V(vs.SCE)。此体系尚未见报道。我们以此体系测定生物样中微量铜,结果满意。 1 试验部分 1.1 仪器与试剂 JP-2型示波极谱仪(成都仪器厂) 三电极系统 铜标准溶液:101μg·ml~(-1),1μg·ml SAF乙醇溶液:1.0×10~(-3)mol·L~(-1) 柠檬酸盐溶液:0.5mol·L~(-1)柠檬酸三铵-0.01mol·L~(-1)柠檬酸     

尼可地尔的极谱催化波法测定

在 pH8.2±0.1的0.1mol·L -1NH3 -NH4Cl -4mmol·L -1KIO3 介质中,尼可地尔在 -1.45V处产生一个灵敏的极谱催化波 ,灵敏度比无KIO3 存在的还原波增大约15倍 ,且峰形得到了显著的改善 ,便于分析测定 ;线性范围为5×10 -7～1×10 -15mol·L -1;对尼可地尔片剂的测定结果与标示量吻合。     

萘丁美酮的极谱波特征及其分析应用

在NaH2PO4-Na2HPO4(pH=9.0)缓冲溶液中,萘丁美酮在-0.62V处产生一个灵敏的极谱波.导数波高与萘丁美酮的浓度在0.5～25.0μg/mL范围内呈良好的线性关系,检出限为0.06μg/mL.通过对萘丁美酮的极谱波行为的分析,探讨了电极反应机理,建立了测定微量萘丁美酮的分析方法.     

光谱透射比标准物质的研究

研制了紫外、可见、近红外光谱区通用光谱透射比较标准物质。以高纯熔融石英为基片材料，镍铬合金的镀膜材料，采用双光楔对称光胶结构以消除同色杂散光的影响，对镀膜进行光胶处理以保证膜层的强度、稳定性及光学中性，采用高精度分光光度测量装置作为定值手段的以保证准确的定值，设计定位保护架以消除多次反射误差。该光度标准适用的光谱范围的200-2600nm，光谱透射比定值不确定度为0.5%。     

SPECTRAL CHARACTERISTICS OF THE EXCITED STATES OF THE PRODUCT OF THE CHEMILUMINESCENCE OF LUMINOL*

Abstract— In dimethylsulfoxide the emission spectrum of luminol chemiluminescence is red-shifted by 300 cm^-1 from the photoexcited fluorescence of the product 3-aminophthalate dianion, while in aqueous solvent the two spectra are identical. The spectral properties of the product dianion have been measured in aqueous solvent and in a number of aprotic solvents, both at room temperature and at 77°K. The ground states and the excited states from which emissions are observed are characterized. Two alternatives are presented to explain the aprotic emission spectra.     

ON THE ACCURACY OF DIFFERENTIAL MEASUREMENTS OF THE MINIMAL ERYTHEMA DOSE: INFLUENCE OF THE DISCRETENESS OF THE SCALE

The minimal erythema dose (MED) is often used as a quantity by which the influence of certain treatments of the skin can be measured. Differential measurements are performed by assessing the difference of the MED on the skin treated in some way and the untreated skin.
As the MED-measuring scale is discrete, the question is sometimes raised whether it is possible to measure differences smaller than one scale unit. In the present paper it is shown that this is indeed possible; in principle the discreteness of the scale does not impose any restriction on the smallest value of the difference that can be measured. The discreteness of the scale introduces an extra random variation into the measurement. This variation is estimated theoretically. It is automatically included in the usual error analysis.
The discreteness variance is small when compared to other variance components, which are computed from an analysis of variance of actual experiments. Reducing the discreteness variance, by reducing the dose decrement of the MED-measuring scale, therefore, does not enhance the overall accuracy considerably. Finally, it is found that the assessments of the MED by the various observers do not differ significantly from each other, and that multiple assessments do increase the accuracy, especially for small effects.     

丙烯聚合络合催化剂形成过程的研究

以倍半物为还原剂还原TiCl_4,经异戊醚络合处理,然后在TiCl_4己烷溶液中35℃条件下热处理,制得对丙烯聚合具有高活性和高定向度的络合催化剂。研究了制备过程中各步反应产物的组成和结构特征,并讨论了TiCl_3低温晶型转变机理。     

对苯二胺衍生物的光催化氧化

以ＴｉＯ２作为催化剂，利用波长＞３３０ｎｍ的光辐照研究了Ｎ－取代的对苯－二胺衍生物的光催化氧化。研究表明，氧分子与光生电子 反应生成羟基自由基，羟基自由基氧化ＰＰＤｓ，生成醌二亚胺，后者在羟基的进攻下脱氨生成苯醌，苯醌继续光解无机化。ＰＰＤｓ光催化氧化近似遵循一级反应动力学，醇类和硫酸根离子可抑制ＰＰＤｓ的光催化氧化。催化剂表面荷影响电子转移速率，从而控制光催化氧化的反应速率。     

分光光度法低浓度区不成线性关系的探讨

本文研究分光光度法低浓度区不成线性的有关因素及其克服方法,以铝-二甲酚橙体系为例,通过对体系不同条件下吸收光谱及其等色点的研究,发现当体系pH渐变时(铝,二甲酚橙浓度固定不变),曲线簇现两个等色点.从对等色点的分析,证明体系形成络合物须按一个反应式进行才能出现等色点,而与反应式是否涉及到两个或三个有色化合物无关.若同时按两个反应式进行,则不能得到等色点,测定时也无线性关系.所以用这个体系进行铝的测定,铝浓度的变化范围只能限于存在等色点的区间才有线性关系. 为了克服常法测定铝时不符线性的现象,本文采用的方法是在二甲酚橙中预先加适量的铝作为显色剂,使反应严格按一个反应式进行,所得结果为一直线.     

六氟丙烯等离子体聚合机理研究

<正> 在以前的工作中,我们曾应用色谱-质谱(GC-MS)及顺磁共振(ESR)等方法研究了四氟乙烯和三氟氯乙烯等离子体聚合过程中气体冷凝物的组成及结构,提出自由基引发聚合反应机理。本文用类似方法研究六氟丙烯(HFP)等离子体气体冷凝物的组成与结构和冷凝物的ESR信号及其从低温到高温的变化规律,证实了自由基的稳定性并提出气相聚合反应机理。     

THE COMPLEXITY OF THE FLUORESCENCE OF CHLORELLA PYRENOIDOSA

Abstract— The complexity of the room-temperature emission spectrum of Chlorella was investigated by a matrix analysis method. This approach revealed the presence of two independently fluorescent components in the short-wave region of the spectrum. These components, maximal at about 687 and 695 nm, appeared to correspond to the fluorescence of the bulk pigments of PS II and PS I respectively. The analysis was insensitive to the individual species within the photosystems. As such, other minor fluorescent species, usually observed at low temperatures, which presumably correspond to fluorescence from the trapping centres, did not appreciably complicate the analysis. The absorption spectra of the two photosystems were calculated from the fluorescence data. The results were similar to those that have been obtained by other workers from oxygen evolution and DCMU poisoning data but differed from those obtained by computer analysis of the absorption spectrum. Addition of reduced DCPIP was observed to reverse the increase in fluorescence yield and changes in the spectral distribution of emission taking place on poisoning the algae. The correlation between this and the catalysis of photophos-phorylation in aged or poisoned chloroplasts was noted. This correlation was tentatively interpreted as evidence for a direct interaction between the donor system and the photochemical apparatus associated with PS II, rather than with a member of the electron transport chain as is normally assumed.     

纳米SiO2锚固光敏基团引发MMA光接枝聚合研究

对纳米SiO2进行了锚固光引发剂的表面修饰,进而引发甲基丙烯酸甲脂(MMA)光接枝聚合制备有机/无机复合粒子.纳米SiO2粒子首先用氯化亚砜进行表面氯化,再与光引发剂2-羟基-4-(2-羟基乙氧基)-2-甲基苯丙酮(Irgacure2959)反应从而锚固上光引发剂.通过紫外光引发MMA在经过修饰过的纳米SiO2表面上进行表面光接枝聚合.采用IR、TGA和TEM等方法表征了接枝前后纳米粒子的变化,证明了表面接枝物的存在,并研究了不同反应条件对单体转化率、接枝率和接枝效率的影响.研究结果表明,搅拌对接枝过程的影响比较显著.TGA结果显示未搅拌聚合时接枝率只能达到比较小的程度,而在搅拌条件下180min内MMA的接枝率可达到110%.