在SLS等表面活性剂存在下,用新显色剂5-Br-TADAP胶束增溶分光光度法测定钴

在SLS等表面活性剂存在下,钴(Ⅱ)与新显色剂2-(5-溴-2-噻唑偶氮)-5-二乙氨基苯酚(5-Br-TADAP)在pH6—9时形成紫红色电中性的胶束增溶络合物。钴在络合物中以钴(Ⅱ)形式存在,Co(Ⅱ):5-Br-TADAP=1∶2,其表观稳定常数为3.5×10~(11)(20℃,μ=0.1)。据此确定了Co(Ⅱ)-5-Br-TADAP络合物的结构。该络合物的λ_(max)为590nm,ε_(590)为8.24×10~4L·mol~(-1)·cm~(-1)。Co(Ⅱ)-5-Br-TADAP络合物一旦形成后,加入的EDTA不再能将其分解,但能分解许多其他金属离子与试剂形成的络合物。在25毫升体积中,钴量在0—20微克范围内遵守比耳定律。本法简便、快速、准确可靠,将其用于低合金钢中小量或痕量钴的测定,取得了满意的结果。     

新显色剂5-Br-TADAP萃取分光光度法测定铁

研究了铁(Ⅱ)与新显色剂2(5溴2噻唑偶氮)-5二乙氨基苯酚(5-BrTADAP)的显色反应.它们在pH 7-10的溶液中形成难溶于水的1∶2棕色络合物,其表观稳定常数为3.94×10~(10)(20℃).用氯仿萃取的Fe(Ⅱ)5 Br TADAP络合物在572nm和772nm有两个吸收峰,其表观摩尔吸光系数分别为3.94×10~4L·mol~(-1)·cm~(-1)和3.10×10~4L·mol~(-1)·cm~(-1),灵敏度是1.10二氮杂菲法的34倍.其他金属离子与该试剂形成的络合物在近红外区的772mm附近均无吸收,因此在772mm处分光光度测定痕量铁有很高的选择性.在10毫升体积中,铁量在0-25微克范围内遵从比耳定律.本法简便、快速、准确可靠,将其用于黄铜和高硅铝合金中铁的测定,取得了令人满意的结果.     

新有机试剂BTASPAP与镍(Ⅱ)的水相显色反应

本文详细研究了新有机试剂2-(2-苯并噻唑偶氮)-5-磺丙氨基苯酚(BTASPAP)与镍(Ⅱ)的水相显色反应.Ni(Ⅱ)与BTASPAP在pH3.5～6.5范围内形成稳定的、易溶于水的、带负电荷的1:2红色配合物,其表观稳定常数为1.99×10~9(20℃,μ0.1),吸收光谱的λ_(max)为550nm,对比度高达105nm,表观摩尔吸光系数ε_(550)为3.40×10~4L·mol~(-1)·cm~(-1)。建议了配合物的结构。在0-36μgNi(Ⅱ)/25ml范围内遵从比耳定律。加入硫脲作掩蔽剂和用NH_3-NH_4CI预分离干扰元素可提高方法的选择性。本法简便、快速、准确可靠,已成功地用于合金钢中痕量镍的测定。     

5-(H-酸偶氮)-8-氨基喹啉与铜显色反应研究应用

研究了 5- (H -酸偶氮 ) - 8-氨基喹啉 (HAQ)与铜的显色反应 ,在 pH =4.2HAc -NaAc缓冲介质中 ,乳化剂 -OP存在下 ,HAQ与铜反应生成 2∶1稳定络合物 ,λmax=550nm ,ε =4.87× 1 0 4 L/mol·cm。铜含量在 0～ 1 6μg/2 5mL内符合比尔定律 ,方法用于精铅样品中铜含量的测定 ,结果令人满意。     

新显色剂5-硝基吡啶偶氮二羧甲氨基苯酚的合成及其分光光度法测定镍的研究

合成了新有机显色剂5-硝基吡啶偶氮二羧甲氨基苯酚,即2-(5-硝基-2-吡啶偶氮)-5-二羧甲基苯酚(5-NO_2-PADECAP)。在 pH5.5的乙酸-乙酸钠介质中,Ni(Ⅱ)与5-NO_2-PADECAP 形成1:2(M:R)可溶而稳定的深色配合物,其吸收峰为570nm,摩尔吸光系数为1.43×10~5L·mol~(-1)·cm~(-1)。0～19μg/25mL 的Ni(Ⅱ)符合比尔定律。以5-NO_2-PADECAP 为显色剂。光度法测定了污水中和合金钢中的微量镍,结果可靠。     

4-(6′甲基苯并噻唑-2′-偶氮)-3,5-二氨基吡唑与钯显色反应的研究和应用

对6种苯并噻唑偶氮吡唑化合物的分析特性进行了探讨,着重研究了4—(6′—甲基苯并噻唑-2′-偶氮)-3,5-二氨基吡唑(MBTAP)与钯离子显色反应的光度性质。在非离子表面活性剂 Brij35存在下与钯离子形成橙红色的配合物。适宜的 pH 值范围为9.0～10.5.配合物的最大吸收波长为510nm,表观摩尔吸光系数为3.01×10~4L·mol~(-1)·cm~(-1)。钯在0～14μg/25mL,范围内服从比尔定律.显色体系可稳定11h。在柠檬酸存在下可消除 Fe~(3+)、Co~(2+)、Cu~(2+)、Ni~(2+)等离子的干扰。     

meso-四(4-磺酸基萘基)卟啉与痕量铜显色反应研究

研究了铜(Ⅱ)与meso-四(4-磺酸基萘基)卟啉(简称TNPS_4)的显色反应,在pH为2.85的HCl-邻苯二甲酸氢钾缓冲溶液中,铜与TNPS_4生成稳定的1∶1型黄绿色的配合物,其最大吸收波长为418nm,表观摩尔吸光系数为3.08×10~5l·mol~(-1)·cm~(-1)。Cu(Ⅱ)的浓度在0～120ng·ml~(-1)的范围内符合朗伯-比尔定律。方法简单,灵敏度高,选择性较好,用于矿石中微量Cu(Ⅱ)的测定,获得了较满意的结果。     

镉试剂与铜（Ⅱ）配合物光度特性的研究及其应用

较系统地研究了镉试剂 A(Cadion A)和镉试剂2 B(Cadion 2 B)分别与铜(Ⅱ)显色反应的光度特性。发现 Triton X-100对配合物的测定有显著的增溶、增敏作用。其适宜 pH 分别为9.5～11.0、8.3～9.5。最大吸收波长分别为500 nm、540 nm。表观摩尔吸光系数分别是1.35×10~5L·mol~(-1)·cm~(-1)、1.13×10~5L·mol~(-1)·cm~(-1)。本法操作简便,显色稳定,是目前光度法测 Cu(Ⅱ)灵敏度高的显色反应之一。用以直接测定铝合金、工业废水中的微量铜,结果满意。     

新试剂3,3'-二甲基-4,4'-二(2-重氮氨基噻唑)联苯与铜的显色反应及其应用

研究了一个新试剂3,3' 二甲基 4,4' 二(2 重氮氨基噻唑)联苯(DDATBP)与Cu(Ⅱ)的显色反应,并建立了一个测定铜的光度分析新方法。在pH10.5的缓冲介质和Tween 80存在下,沸水浴中加热10min后,铜与DDATBP发生显色反应并形成褐色络合物,其最大吸收波长位于500nm,表观摩尔系数ε为1.60×104L·mol-1·cm-1,且铜的质量浓度在0.10～3.6μg/mL范围内符合比尔定律。用该方法测定了食品中的微量铜,结果满意。     

3,3′-二甲基-4,4′-(2-氨基噻唑偶氮)联苯与季铵型阳离子表面活性剂的显色反应及其应用

研究了 3, 3′ 二甲基 4, 4′ (2 氨基噻唑偶氮)联苯(DATABP)在pH为 12. 0 ~12. 5的强碱性介质中与溴化十六烷基三甲铵(CTMAB)、溴化十六烷基吡啶 (CPB)及溴化十四烷基吡啶 (TPB) 3种的反应。实验表明DATABP与各表面活性剂均形成络合比为 1∶1的绿色络合物。对CTMAB、CPB及TPB体系,络合物的最大吸收波长分别为 620nm、630nm和 640nm,表观摩尔吸光系数分别为 5. 60×103、5. 52×103 和 3. 07×103L·mol-1·cm-1。用所建立的方法测定了水中的CPB,结果满意。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。