DBM-MSA 光度法测定食品包装材料和容器中的铅

研究了新显色剂二溴对甲基偶氮甲磺（ＤＢＭ－ＭＳＡ）与铅的显色反应,在量浓度为０．２４ｍｏｌ／Ｌ的Ｈ３ＰＯ４介质中,铅在ＤＢＭ－ＭＳＡ形成稳定的蓝色配合物,其组成比为ｎ（Ｐｂ）：ｎ（ＤＢＭ－ＭＳＡ）＝１：２,最大吸收波长为６４２ｎｍ,表观摩尔吸光系数达９．５×１０＾４,铅的质量浓度在０－１５μｇ／２５ｍＬ服从比耳定律,测定量浓度为１０μｇ／２５ｍＬ的铅时大多数金属离子的允许量在ｍｇ级,用于食品包装材     

示波极谱法测定锌锭中的微量锡

微量锡的测定文献 [1～ 5 ]已有报道 ,多采用比色法、ＩＣＰ ＡＥＳ法和ＡＡＳ法 ,有些分析步骤冗长、工作量大 ,有些需要昂贵的仪器设备。本文将样品简单处理后 ,用示波极谱法 ,在氯化钠底液中直接测定锌锭中微量锡。1　试验部分1 1　主要仪器与试剂ＪＰ 2型示波极谱仪 ;饱和甘汞电极 ,铂电极 ,滴汞电极的三电极系统 (成都仪器厂 ) ;锡标准溶液 :1 0ｍｇ·ｍＬ- 1 用光谱纯金属锡按常规法配制而成 ;锡标准工作溶液 :1 0 0 μｇ·ｍＬ- 1 ,使用时用水逐级稀释而成 ;ＮａＣｌ底液 :30 0ｇＮａＣｌ溶于 1 0 0 0ｍＬ水中 ,摇匀 ,备用 ;Ｂａ…     

Keggin结构钨磷酸／聚丙烯酰胺复合物的制备及光性质研究

无机 有机复合材料的合成是目前令人关注的研究领域[1 ] ,以杂多化合物作为多核配合物 ,通过化学键或氢键作用与有机底物结合形成电荷转移物质的研究已得到广泛重视[2～7] .本文以Ｋｅｇｇｉｎ结构钨磷酸和聚丙烯酰胺为原料合成了钨磷酸 /聚丙烯酰胺复合物 ,表征了其结构特征及光致变色性质 .1　实验方法Ｋｅｇｇｉｎ结构Ｈ3[ＰＷ1 2 Ｏ40 ]·6Ｈ2 Ｏ按文献 [8]方法制备 ,含水量用热重分析测定 .将聚合度为1 1 0 0 0± 1 1 0的聚丙烯酰胺 (ＰＡＭ ) 0 5ｇ、钨磷酸 0 0 5ｇ分别溶解在 50ｍＬ和 1 0ｍＬ水中 ,两者混合后于 65℃下搅拌反应 2…     

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…     

平台石墨炉原子吸收法测定高温镍基合金中铋

本文用１ｍｇ／ｍＬ镍和０．２ｍｇ／ｍＬ钯作混合基体改进剂，提高了测定铋的灰化温度和抗干扰能力，且灵敏度几乎不变。可不经分离样品基体，直接用平台石墨炉原子吸收法测定高温镍基合金中铋。方法特征量为１８ｐｇ，检出限为０．０８１μｇ／ｇ。对含０．３－０．７μｇ／ｇ铋的镍基样品测定，相对标准偏差为３．０％－５．９％，回收率在８５％－１１９％之间。     

铅-钙合金光谱标样的制备与标定

通常用的铅 钙合金光谱标样比较缺乏 ,且钙含量范围一般只能做到 0 .2 %以下。本文试验此类合金光谱标样的制备与标定。可制备出钙含量范围从0 .0 1%～ 2 %的铅 钙合金标样 ,采用直读光谱分析法检验其均匀性 ,用原子吸收光谱法和ＥＤＴＡ容量法分析定值[1,2 ] ,制备出了结果满意的标准样品。1　试验部分1.1　主要仪器ＧＧＸ 5型原子吸收分光光度计 ,附钙空心阴极灯 (北京地质仪器厂 )。ＡＲＬ 4 4 6 0直读光谱仪 (瑞士ＡＲＬ公司 )ＧＷ 0 .15型中频感应炉1.2　试验方法利用中频感应炉、石墨坩埚 ,加金属铝作保护 ,将铅和钙于 (70 0± 30 )…     

原子吸收法测定中草药中钙、镁、铁、锌、铜和锰

钙、镁、铁、锌、铜、锰都是人体必不可少的元素 ,而中草药中这些元素的测定 ,无论是从中医药学还是营养卫生学的角度而言 ,都显得极其重要和必不可少[1 ,2 ] 。本文采用原子吸收分光光度法连续测定中草药中的钙、镁、铁、锌、铜、锰。1　实验部分1 .1　仪器与试剂Ｚ 80 0 0偏振塞曼原子吸收分光光度计 ,配火焰和石墨炉原子化器 (日本日立公司 )。ＬａＣｌ3溶液( 1 0 0ｇ/Ｌ) ;ＳｒＣｌ2 溶液 ( 5 0ｇ/Ｌ) ;钙、镁、铁、锌、铜、锰混合标准储备液 (Ｃａ、Ｍｇ、Ｆｅ 2ｇ/Ｌ ,Ｍｎ 1ｇ/Ｌ ,Ｚｎ、Ｃｕ 0 5ｇ/Ｌ)。1 .2　样品液的制备准确称…     

阳极溶出伏安法测定痕量汞的研究

痕量汞的测定方法有很多[1 ] 。原子吸收法虽然具有较高的灵敏性 ,但是仪器设备昂贵 ,分析步骤较繁琐。近年来 ,化学修饰电极阳极溶出伏安法在对汞痕量分析方面的研究报道也不少[2～3] ,测定的检测限一般在 1 0 - 6～ 1 0 - 9ｇ·ｍｌ- 1 ,但它容易产生记忆效应 ,洗脱不良。本文以玻碳电极为工作电极 ,在ＨＣｌ ＮａＣｌ Ｃｄ2 +中 ,示差脉冲阳极溶出伏安法 (ＤＰＳ)测定痕量汞 ,汞的平均回收率达80 %。1　实验部分1 1　主要仪器与试剂ＰＡＲ— 384极谱仪 (美国 ) ;三电极系统 :工作电极为玻碳电极 ,参比电极为Ａｇ/ＡｇＣｌ电极 ,对电极为…     

微波消解火焰发射光谱法测定奶粉中钙

微波消解样品具有快速、分解完全、元素无挥发性损失、玷污小、空白值低等优点 ,目前在分析领域中应用越来越多[1] 。测定钙 ,通常用原子吸收光谱法和ＥＤＴＡ容量法[2 ] ,也有报道用火焰发射光谱法直接对水样中钙进行测定[3] 。本文采用微波消解乳样 ,样液用 2 5ｇ·Ｌ- 1镧溶液稀释至一定体积后用火焰发射光谱法测定 ,用标准曲线法定量。该法线性范围大 ,重复性好 ,无需钙空心阴极灯 ,结果满意。1　试验部分1.1　仪器与试剂ＡＡ6 80 0原子吸收光谱仪 (日本岛津 )ＭＫ Ⅱ型压力自控微波溶样系统 (上海新科微波技术研究所 )镧溶液 :2 5 ｇ·…     

PBA光纤化学传感器在线监测家兔口服呋喃妥因的尿药浓度

芘丁酸光纤化学传感器（ＰＢＡ—ＦＯＣＳ）用于在线测定家兔口服呋喃妥因后排出尿液中的药物浓度。方法的检出限为１．３μｇ／ｍＬ，线性范围１～１００μｇ／ｍＬ，精密度（ＲＳＤ）１．５～３．５％，回收率在９５．０～１００％之间。４只雄性家兔的尿药浓度—时间曲线显示达峰时间为３．５ｈ，６ｈ累积尿药排出百分率为２１％。实验结果显示传感器、测定池和仪器系统设计合理。可实时、在线测定生物体液中的药物浓度并达到实用水平。     

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。     

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.     

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。     

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。