吸光光度法测定水中微量阴离子表面活性剂

目前用于测定水中阴离子表面活性剂的国标方法是亚甲蓝吸光光度法。该法不仅操作繁琐、准确度差、易受各种共存物的影响 ,而且灵敏度低 ,最低检测浓度仅为 0 .0 5ｍｇ·Ｌ- 1,难以满足残留量的测定要求。本文在前人工作的基础上运用Ｃｏ ＰＡＤＡＰ方法进行水中微量阴离子表面活性剂试验 ,最低检测浓度为 0 0 2ｍｇ·Ｌ- 1,干扰物质少 ,准确度和重现良好。1　试验部分1.1　主要仪器与试剂72 1型分光光度计Ｃｏ ＰＡＤＡＰ的合成 :称取 5 Ｂｒ ＰＡＤＡＰ 1.0 0 ｇ溶于 30ｍｌ盐酸 (2ｍｏｌ·Ｌ- 1)中 ,加入 50 ｇ·Ｌ- 1ＣｏＣｌ2·6Ｈ2 Ｏ…     

紫外吸光光度法测定化妆品中木瓜蛋白酶的活力

样品用磷酸盐 半胱氨酸 ＥＤＴＡ缓冲溶液搅拌溶解后 ,选择一定的 ｐＨ值和温度条件 ,样品中的木瓜蛋白酶能将加入的酪蛋白水解生成可溶解的氨基酸 ,末水解的酪蛋白用三氯乙酸沉淀后过滤 ,溶解的水解产物用紫外吸光光度法测定[1] 。1　试验部分1.1　试剂与仪器磷酸钠溶液 :0 .0 5ｍｏｌ·Ｌ- 1,称取十二水磷酸氢二钠 1.79ｇ溶解于 10 0ｍｌ水中。柠檬酸溶液 :0 .0 5ｍｏｌ·Ｌ- 1,将柠檬酸一水合物1.0 5ｇ用 10 0ｍｌ水溶解。缓冲溶液 :称取十二水磷酸氢二钠 17.89ｇ溶于80 0ｍｌ水中 ,再将ＥＤＴＡ钠盐二水合物 14.0 ｇ和盐酸半胱氨酸一…     

新试剂1-(2,6-二溴-4-硝基苯)-3-(4-硝基苯)-三氮烯与汞的显色反应及应用

三氮烯试剂与第ＩＢ、ＩＩＢ族金属元素有高灵敏的显色反应 1 [1] ,可用来测定样品中微量的Ｃｄ2 + 、Ｈｇ2 + 、Ｚｎ2 + 、Ｎｉ2 + 。随着表面活性剂引入该显色体系 ,使该试剂与金属离子显色反应的灵敏度有了很大的提高。目前报道的三氮烯显色剂与Ｈｇ2 + 显色反应的灵敏度一般在ε =1 .0× 1 0 5Ｌ·ｍｏｌ-1·ｃｍ-1左右 ,但也有部分试剂的灵敏度较高 ,如ＯＣ Ｃａｄｉｏｎ[2 ] 的ε =1 .77× 1 0 5Ｌ·ｍｏｌ-1·ｃｍ-1,ＤＮＡＡＢ[3 ] ε=1 .74× 1 0 5Ｌ·ｍｏｌ-1·ｃｍ-1,ＭＤＡＡ[4]的ε=1 .8× 1 0 5Ｌ·ｍｏｌ-1·ｃｍ-1,ＡＰＤ…     

吸光光度法测定空气中一甲胺的改进

车间空气中一甲胺的测定 ,目前推荐的方法仅为对硝基苯胺重氮盐比色法[1] ,作者在工作中发现 ,该法中对硝基苯胺重氮盐溶液的加入量对其影响很大 ,为此 ,进行了一系列探讨并加以改进。1　试验部分1.1　仪器与试剂72 1型分光光度计吸收液 :0 .0 1ｍｏｌ·Ｌ- 1盐酸溶液缓冲液 :80ｍｌ蒸馏水内溶解 4 .0 8ｇ磷酸二氢钾、1.6ｇ硼砂 ,再加入 5 .0ｍｏｌ·Ｌ- 1氢氧化钠溶液 6.35ｍｌ,用水稀释至 10 0ｍｌ亚硝酸钠溶液 :5 .0 ｇ·Ｌ- 1对硝基苯胺盐酸溶液 :1.0 ｇ·Ｌ- 1,将 0 .1ｇ对硝基苯胺溶于 1.0ｍｏｌ·Ｌ- 1盐酸 10 0ｍｌ中。对硝基苯胺重…     

硅钼蓝光度法测定五氧化二钒中微量硅

采用氢氧化钠对试样进行前处理 ,在硝酸 0 .0 8～ 0 .4 0ｍｏｌ·Ｌ- 1酸度下 ,硅与钼酸铵形成硅钼酸络离子 ,在硫酸 0 .8～ 1.6ｍｏｌ·Ｌ- 1酸度下 ,被还原生成硅钼蓝 ,借此进行光度测定[1] ,硅量在 10～ 10 0 μｇ/5 0ｍｌ范围内遵守比耳定律。1　试验部分1.1　仪器与试剂72 2光栅分光光度计硅标准溶液 :10 μｇ·ｍｌ- 1五氧化二钒标准溶液 :2 .5ｍｇ·ｍｌ- 1,称取五氧化二钒 (99.99%) 0 .2 5 0 0 ｇ置于 30 0ｍｌ聚四氟乙烯烧杯中 ,加入 10 0ｇ·Ｌ- 1ＮａＯＨ溶液 10ｍｌ,低温加热溶解 ,取下 ,加入数滴酚酞 ,用ＨＮＯ3 (1+ 1)调至无…     

催化动力学法测定人发中痕量硒

催化动力学褪色法测定痕量硒已有报道[1 ,2 ] ,但大都存在Ｆｅ3+、Ｃｕ2 +等共存离子的干扰。在实际分析中常需对样品进行繁琐的预处理。实验研究了在盐酸溶液中 ,以ＥＤＴＡ作掩蔽剂 ,痕量硒催化氯酸钾氧化 5 Ｂｒ ＰＡＤＡＰ褪色反应及其动力学条件 ,以加硒催化反应与不加硒非催化反应的吸光度之差△Ａ对温度 1 /Ｔ作图得一直线 ,由Ａｒｒｈｅｎｉｕｓ式求得该反应的活化能Ｅａ=94ｋＪ/ｍｏｌ,建立了测定硒的新方法。方法检测限为 5.7× 1 0 - 5μｇ/ｍｌ,Ｓｅ(Ⅳ)的测定范围为 0～ 0 .4μｇ/ 2 5ｍｌ,用此法测定人发中痕量硒 ,结果令人满…     

饲料卫生标准中铅测定标准系列制作的改进

铅是反映饲料产品质量及卫生状况的一项重要指标 ,在进行产品监督检验时 ,铅是常检的项目。在采用ＧＢ130 80 - 1991标准检验方法进行样品检验中 ,发现由于标准系列的酸度很低 ,甲基异丁酮的用量较小 ,且在容量瓶中进行萃取易造成有机萃取不够完全充分 ,出现标准曲线不呈线性或相关性较差的现象。本文作了以下试验 ,并提出了改进的方法。取一组 7支 2 5ｍｌ具塞比色管 ,1号管作试剂空白用 ,其余加入 5 μｇ·ｍｌ- 1铅标准溶液 4ｍｌ。加入1ｍｏｌ·Ｌ- 1盐酸 2ｍｌ,加水至 2 0ｍｌ,加入 1ｍｏｌ·Ｌ- 1碘化钾溶液 2ｍｌ,振动摇匀 ,加入 5 0…     

铁矿中全铁、二氧化硅和氧化钙的测定

铁矿的质量检查和入炉铁矿全铁、二氧化硅和氧化钙的测定 ,是中小型铁厂化验室相当繁重的一项日常工作 ,表现为试样数量多 ,测试频率高 ,同时要求较快地报出结果。采用既经济又快速实用的分析方法 ,对指导高炉生产有着十分重要的意义。1　试验部分1.1　主要仪器与试剂72 1ＳＸ分光光度计钨酸钠溶液 :5 0ｇ·Ｌ- 1,称取Ｎａ2 ＷＯ4 ·2Ｈ2 Ｏ 5ｇ溶于 5 0ｍｌ水中 ,加磷酸 10ｍｌ,用水稀释至 10 0ｍｌ ,摇匀。三氯化钛溶液 :将 15 0～ 2 0 0ｇ·Ｌ- 1三氯化钛用盐酸 (1+ 1)稀释 3倍硫酸铜溶液 :2 0ｇ·Ｌ- 1硫 磷混酸 :Ｈ2 ＳＯ4 ∶Ｈ2 ＰＯ…     

EDTA滴定法测定钼铁及其合金中钼

关于钼铁中主量元素钼的分析[1] ,现有的 8 羟基喹啉重量法[2 ] ,准确度虽高 ,但操作周期冗长 ;而比色法的灵敏度远达不到分析要求 ,且相对误差很大 ,因此 ,两者均不能适应厂矿快速、准确的分析要求。ＥＤＴＡ滴定法测定钼铁及其合金中的钼 ,对于10 %～ 60 %的钼含量的分析 ,做到了快速、准确 ,相对误差小于 1%。1　试验部分1.1　主要试剂ＥＤＴＡ溶液 :0 .0 1ｍｏｌ·Ｌ- 1,称取ＥＤＴＡ3 72 2 4 ｇ ,溶解于水中 ,移入 1Ｌ容量瓶中 ,以水稀释至刻度 ,摇匀。硝酸铋溶液 :0 .0 1ｍｏｌ·Ｌ- 1,称取Ｂｉ(ＮＯ3) 3·5Ｈ2 Ｏ 4 .85 0 7ｇ于 2 5 …     

偶氮氯膦Ⅰ光度法测定镁

测定铜矿中镁的方法不少[1] ,但均存在一些不足之处。本文采用光度法测定镁的显色剂为偶氮氯膦Ⅰ (ＣＰＡ Ⅰ ) ,于ｐＨ 10左右的硼砂 氢氧化钠缓冲液中显色 ,试验表明 ,方法的准确度和精密度能满足分析要求。1　试验部分1.1　主要仪器与试剂75 4型分光光度计镁标准溶液 :10 μｇ·ｍｌ-1,称取于 60 0℃灼烧 1ｈ后的高纯氧化镁 0 .10 0 0ｇ于烧杯中 ,加ＨＣｌ(1+ 1)10ｍｌ,盖表皿 ,低温溶解后 ,加水定容于 1Ｌ容量瓶中 ,吸取溶液 5 0ｍｌ,加水稀至 5 0 0ｍｌ容量瓶中。显色剂 :0 .30 0 0ｇ·Ｌ-10 .30 0ｇＣＰＡ Ⅰ溶于 1Ｌ水中氢氧化钠 …     

利用手持技术改进测定乙醇分子结构实验

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。     

光谱仪测试范围的扩展

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。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

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.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

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。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

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.     

Calculation of enthalpies of hydrogenation of hydrocarbons

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.     

非那雄胺合成工艺改进

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。