双波长分光光度法同时测定电镀液中的钴和镍

考察了以4-(2-吡啶偶氮)-间苯二酚(PAR)作为显色剂,用双波长分光光度法同时测定电镀液中的钴和镍的最佳实验条件.在pH=8.0的氯化铵-氨水缓冲溶液中,以λmax.Co=512nm,λ参比.Co=482nm为测定钴的波长对,Co的线性方程为y=0.0907x-0.0162,线性范围为8.00～22.00μg/25mL;以λmax,Ni=496nm,λ参比,Ni=526nm为测定镍的波长对,Ni的线性方程为y=0.363x 0.0197,线性范围为4.00～14.00μg/25mL.对电镀液进行加标回收实验结果表明,该方法精密度高,结果准确,令人满意.     

光度法同时测定合金镀液中Co2+与Ni2+

提出采用双波长分光光度法同时测定镍钴合金镀液中Co2 与N i2 的含量。通过筛选确定PAR乙醇液作为显色剂。测得Co2 与N i2 的最大吸收波长分别为510 nm,490 nm,以此作为测定波长。该法的测量范围为30~1 200μg/LCo2 ,25~1 000μg/L N i2 。讨论了显色剂用量、酸度及显色时间对吸光度的影响,从而确定了显色条件。对4种镍-钴合金镀液进行加标回收实验的结果表明,该法精确度高,回收率达到99.7%,操作简单,实用性强。     

丽春红S褪色光度法测定锡-钴合金镀液中的钴

在90℃水浴中,Co2+能催化铋酸钠氧化丽春红S褪色,据此建立了一种褪色光度法测定Co2+的新方法。Co2+在0~50μg/mL范围内遵守比尔定律,表观摩尔吸光系数为1.814×103 L/(mol.cm),最大吸收波长为520 nm,该方法检出限为0.538μg/mL。该方法用于测定锡-钴枪黑色合金镀液中钴的含量,结果令人满意。     

碱性锌-钴合金镀液中锌、钴含量的测定

为获得耐蚀性良好的锌 钴合金镀层 ,必须维持镀液中的锌 钴含量在工艺范围内。采用EDTA滴定和分光光度相结合的方法测定碱性锌 钴合金镀液中的锌、钴含量。介绍了该方法的分析步骤 ,探讨了测量波长的确定 ,亚硝酸钠、镀液共存组分、酸度以及铜离子和铁离子等杂质对测量结果的影响。结果表明 ,在 530nm波长下 ,钴浓度在 0 - 3μg/mL范围内所测吸光度与钴浓度间的关系遵守比耳定律 ,该方法准确度高 ,回收率达 97% - 1 0 3 5%。     

光度法快速测定金-钴-镍-铟合金镀液中的钴

研究了钴离子与4-(2-吡啶偶氮)-间苯二酚(PAR)形成配合物的条件及其光度性质。实验结果表明,在pH6～8的柠檬酸铵介质中,钴离子与PAR形成紫红色配合物,其最大吸收波长位于570nm处,表观摩尔吸光系数ε'570=1.8×104L/(mol·cm),钴质量浓度介于0～2.5μg/mL遵守比尔定律。用硫酸酸化后,配合物不分解,因而方法具有良好的选择性。应用于金-钴-镍-铟合金镀液中钴的测定获得了较满意的结果。     

二溴对甲偶氮羧光度法测定锌钴合金镀液中的钴

研究了显色剂二溴对甲偶氮羧与钴的显色反应。pH=10的柠檬酸铵–氨水溶液中,钴与二溴对甲偶氮羧反应形成蓝色配合物,其最大吸收波长为660nm,表观摩尔吸光系数为1.77×104L/(mol·cm)。25mL溶液中的钴含量为0~80μg,符合比尔定律。该方法可用于锌钴合金镀液中钴的直接测定,相对标准偏差为1.4%~1.9%,回收率为98%~102%。     

RP-HPLC法测定不同产地延胡索中延胡索乙素含量

用RP-HPLC法测定了对不同产地延胡索中延胡索乙素的含量。测定使用Kromasil C18色谱柱(200 mm×4.6 mm,5μm),以甲醇-0.1%磷酸溶液(用三乙胺调至pH 6.09)(V∶V,55∶45)为流动相,流速为1.0 mL/min,检测波长为280 nm。该方法的线性范围是22.0~352.0μg/mL,平均回收率98.6%,RSD=0.4%(n=9)。该法可用于质量控制。     

碱性锌—钛合金镀液中锌、钴含量的测定

为获得耐蚀性良好的锌－钴合金镀层，必须维持镀液中的锌－钴含量在工艺范围内，采用EDTA滴定和分光光度相结合的方法测定碱性锌－钴合金镀液中的锌、钴含量。介绍了该方法的分析步骤，探讨了测量波长的确定，亚硝酸钠、镀液共存组分、酸度以及铜离子和铁离子等杂质对测量结果的影响。结果表明，在530nm波长下，钴浓度在0－3μg/mL范围内所测吸光度与钴浓度间的关系遵守比耳定律，该方法准确度高，回收率达97％－103.5%。     

高效液相色谱法测定磺胺二甲嘧啶的有关物质

目的:用高效液相色谱法测定磺胺二甲嘧啶的有关物质。方法:用Alltima C18(5μm,250 mm×4.6 mm)色谱柱;流动相为13.6 g/L磷酸二氢钾缓冲液(用20 g/L氢氧化钾溶液调节pH至4.50)—甲醇的体积比为55∶45;流速1.0 mL/min;检测波长:275 nm;进样体积:20μL。结果:磺胺二甲嘧啶在80~120μg/mL范围内线性关系良好(r=0.9999),磺胺线性范围为0.15~1μg/mL(r=1.0000),磺胺脒线性范围为0.15~1μg/mL(r=1.0000)。结论:该方法简便、准确、专属性好,可用于磺胺二甲嘧啶含量及有关物质检测。     

高效液相色谱法测定磺胺二甲嘧啶的有关物质

目的:用高效液相色谱法测定磺胺二甲嘧啶的有关物质。方法:用Alltima C18(5μm,250 mm×4.6 mm)色谱柱;流动相为13.6 g/L磷酸二氢钾缓冲液(用20 g/L氢氧化钾溶液调节pH至4.50)—甲醇的体积比为55∶45;流速1.0 mL/min;检测波长:275 nm;进样体积:20μL。结果:磺胺二甲嘧啶在80~120μg/mL范围内线性关系良好(r=0.9999),磺胺线性范围为0.15~1μg/mL(r=1.0000),磺胺脒线性范围为0.15~1μg/mL(r=1.0000)。结论:该方法简便、准确、专属性好,可用于磺胺二甲嘧啶含量及有关物质检测。     

高聚物萃取分离光度法测定Pb2+

利用非挥发性水溶性高聚物的水溶液在无机盐存在下可分成两相的特点,讨论了Pb2+、Cd2+、Co2+、Cu2+、Fe3+、Ni2+、Zn2+混合液中Pb2+的分离和测定条件,实现了Cd2+、Co2+、Cu2+、Fe3+、Ni2+、Zn2+与Pb2+的定量分离和测定,结果表明方法简便、可靠、快速,在Pb2+含量0～4.0μg/mL范围内有良好的线性关系.回收率在95%～105%.     

改型斜发沸石在Na+-Ca2+-Mg2+和NH4+-Ca2+-Mg2+水溶液体系中的离子交换平衡

研究了Na+-Ca2+-Mg2+与钠型斜发沸石和NH4+-Ca2+-Mg2+与铵型斜发沸石的离子交换平衡,分别测定出2个体系的离子交换平衡数据,并利用三维坐标绘制出三元离子交换平衡等温面,计算出改型沸石对体系中离子的分离因数. 结果表明,在Na+-Ca2+-Mg2+溶液体系中,Na+的分离因数>10,Ca2+的在0.4~10之间,Mg2+的小于0.4,斜发沸石离子交换顺序为Na+>Ca2+>Mg2+,且温度升高Ca2+和Mg2+的交换能力增强,而低温则有利于沸石对Na+的选择;在NH4+-Ca2+-Mg2+溶液体系中,NH4+的分离因数>15,Ca2+的在0.2~1.5之间,Mg2+的小于0.2,斜发沸石离子交换顺序为NH4+>Ca2+>Mg2+,且温度升高Ca2+和Mg2+的交换能力增强,NH4+的选择性降低.     

十二烷基磺酸根插层Ni~(2+)-Fe~(3+)/Co~(2+)-Ni~(2+)-Fe~(3+) LDHs及其结构研究

应用水热技术制备了二元Ni2+-Fe3+-CO23- LDHs和三元Co2+-Ni2+-Fe3+-CO32- LDHs,以十二烷基磺酸根离子作为插层客体,通过离子交换反应在酸性溶液中实现了十二烷基磺酸根插层Ni2+-Fe3+ LDHs和Co2+-Ni2+-Fe3+-LDHs。十二烷基磺酸根在Ni2+-Fe3+LDHs层间出现了2种空间导向和排列:即十二烷基磺酸根以单层垂直方向排布和以双层垂直方向排布在层间;十二烷基磺酸根在三元组分Co2+-Ni2+-Fe3+-LDHs层间只有一种空间排列方式,即十二烷基磺酸根以单层垂直方向排布于Co2+-Ni2+-Fe3+-LDHs层间。     

Electronic Structure and Properties of the O2+2, SO2+ and S2+2 Diatomic Dications

Multiply charged ions show novel energetic features which can potentially have useful photophysical properties. In order to investigate these interesting type systems, energy interaction curves for the ground and excited electronic states of O²⁺₂, SO²⁺, and S²⁺₂ have been generated by the ab initio complete active space multiconfiguration self-consistent field (CAS-MCSCF) method. The calculations were carried out in a triple-zeta sp plus double-zeta d Gaussian function basis set using compact effective potentials to replace the core electrons. In order to gauge the accuracy of the results, analogous calculations were carried out on the valence isoelectronic N₂ and NO⁺ systems for which experimental information is available for comparison of geometric and spectroscopic properties. Diverse high energy spectroscopy experiments on O²⁺₂ are interpreted and reconciled using the calculated ground and excited state energy interaction curves. Special attention is paid to the ₃Σ₊^u state, whose location and character have been particularly puzzling. Almost all the dication molecular states studied show the characteristic avoided crossing of diabatic states which gives a trapped equilibrium structure and a barrier to dissociation. These features make the dication kinetically stable, but thermodynamically unstable with an exothermic dissociation energy. The spectroscopy experiments on O²⁺₂ show that these states are experimentally attainable.     

粉煤灰及膨润土对Ni^2＋，Zn^2＋，Cd^2＋，Pb^2＋的吸附研究

研究了粉煤灰和膨润土对溶液中有毒重金属离子Ni~(2 )、Zn~(2 )、Pb~(2 )、Cd~(2 )的吸附能力。动态吸附试验显示,吸附过程是快速的。试验结果表明:粉煤灰对Zn~(2 )的吸附能力和膨润土相当,对Ni~(2 )、Cd~(2 )的吸附能力均大于膨润土。平衡吸附模型说明在高浓度下,Ni~(2 )、Zn~(2 )、Pd~(2 )在粉煤灰中,Ni~(2 )、Pd~(2 )在膨润土中的吸附符合Langmuir模式。试验还表明:随着吸附剂中Ni~(2 )、Zn~(2 )、Pb~(2 )、Cd含量增加,粉煤灰和膨润土对Ni~(2 )、Zn~(2 )、Pb~(2 )、Cd~(2 )的吸附百分率下降。     

Replacing Mg2+ by Fe2+ for RNA-Cleaving DNAzymes

It has been proposed that Mg²⁺ and Fe²⁺ are very similar in interacting with ribozymes and some protein-based enzymes, but their activities with DNAzymes have yet to be studied. Here, the activity of Fe²⁺ as cofactor for a few RNA-cleaving DNAzymes is investigated. 17E is a well-studied DNAzyme that is active in the presence of many different divalent metal ions; it is highly active with Fe²⁺ with an apparent K_d of 29.7±2.3 μm and a k_obs of 1.12±0.11 min⁻¹ in the presence of 1 mm Fe²⁺ at pH 7.5. Fe²⁺ has 21-fold higher activity than Mg²⁺. Six different DNAzymes are then tested, and only the DNAzymes active with Mg²⁺ (17E, 8–17, and E5) are active with Fe²⁺. Fe²⁺ has 25 and one- to twofold higher activity than Mg²⁺ for the 8–17 and E5 DNAzymes, respectively. In pH>7 buffer and in presence of air, 1 mm Fe²⁺ results in a nonspecific degradation of the DNA strand due to reactive oxygen species (ROS). Cleavage reactions in anoxic environment and antioxidant ascorbate can be used to overcome the effect of oxidation. The findings provide insights for potential DNAzyme catalysis in the early Earth, and they further support the similarity between Mg²⁺ and Fe²⁺ in enzyme catalysis.     

The Formation of CrO2+2 in the Reaction of Cr2+ + O2 in Aqueous Acid Solutions

The reduction rate of Cr³⁺ by e_aq was determined, k₈ = 1.7 × 10¹⁰ M^?1 s^?1. The reaction of Cr²⁺ with O₂ was studied, k₂ = 1.6 × 10⁸ M^?1 s^?1. The spectrum of CrO²⁺₂ was obtained both with the pulse radiolysis method and by mixing Cr²⁺ with excess of O₂. It was shown that CrO²⁺₂ decays slowly to yield HCrO^?₄. The results suggest that the reaction of Cr²⁺ with O₂ is a two electron transfer process.     

改性海泡石对废水中Pb2+、Hg2+、Cd2+ 吸附性能的研究

用盐酸溶液对海泡石进行处理和在450℃灼烧,制备出改性海泡石。在动态条件下,研究了改性海泡石对重金属离子Pb2+、Hg2+、Cd2+的吸附效果及吸附条件。同时探讨了改性海泡石对重金属离子Pb2+、Hg2+、Cd2+的吸附机理。含Pb2+、Hg2+、Cd2+的冶金废水经改性海泡石吸附后,重金属离子含量显著低于国家排放标准。     

磷钨杂多酸插层Ni2+-Mg2+-Al3+-LDHs复合材料的合成

利用尿素回流法合成Ni²⁺-Mg²⁺-Al³⁺-LDHs，Ni²⁺-Mg²⁺-Al³⁺-LDHs层状材料经300 ℃焙烧后，以焙烧产物作为前驱体，通过焙烧重组法将磷钨杂多酸成功引入Ni²⁺-Mg²⁺-Al³⁺-LDHs层中，制备磷钨杂多酸插层Ni²⁺-Mg²⁺-Al³⁺-LDHs复合材料。