畜禽养殖场土壤中砷的测定-以水作载流的氢化物发生原子荧光光谱法

为监测畜禽养殖场对周围土壤环境的污染程度,选择重庆市50个养殖场作为样本,对其附近的土壤进行采样分析。将新鲜的土壤样品加入适量的硝酸、盐酸、氢氟酸、高氯酸高温消解后赶酸,最后定容至50 mL,利用以水作载流的氢化物发生-原子荧光光谱仪(WC-HG-AFS)测定了其中的砷(As)含量。结果表明,在5.000~100.000 mg/kg范围内线性相关系数R²=0.99997,检出限为0.074 mg/kg,样品的相对标准偏差(RSD)为1.6%,5份平行样品分析结果的相对偏差分别为6.86%、7.68%、1.12%、13.10%、11.25%,均小于实验室分析质量控制标准相对偏差允许限25.84%,三种标准物质分析结果的标准推荐值的相对误差为2.3%、1.9%、3.1%,均小于其对应的相对误差允许限14.1%、9.8%、12.4%,数据可靠。检测结果表明,除一个检测点外(011属于Ⅱ类土壤),其他养殖区土壤中的总As含量低于《土壤环境质量标准》(GB 15618—1995)中规定的一级标准中As的最高限值15 mg/kg,属于Ⅰ类土壤,目前环境质量较好,畜禽养殖并未对当地环境造成明显危害。     

微波消解-ICP-MS法同时测定土壤中8种重(类)金属元素

通过优化微波消解的温度和时间、消解试剂类型和体积等条件,建立了ICP-MS同时测定土壤中7种重金属(Hg,Cd,Pb,Cr,Zn,Ni,Cu2+)和一种类金属(As)的方法。采用HNO3-HF-H2O2混酸体系,将样品完全消解。各元素线性相关系数≥0.9992,方法检出限为0.02~1.00 mg/kg,日间和日内相对标准偏差≤6.2%,回收率在91.3%~104.9%之间,土壤标准物质GBW07457和NILMA049的测得值与标准值吻合度高。实际土壤样品分析结果显示,Cd是目标区域土壤中的主要污染物,对土壤环境质量影响较高。     

水为载流-原子荧光光谱法同时测定土壤中痕量砷、汞

改变原子荧光光谱法以稀酸为载流的进样方式,以水为载流在新型双道原子荧光光谱仪上同时测定了土壤中的痕量砷(As)、汞(Hg)。方法采用王水水浴加热溶解样品,用50 g/L硫脲-抗坏血酸混合溶液预先将砷还原为+3价,保持10%(体积分数)以上盐酸浓度,不转移直接定容静置后测定。优化了仪器工作条件,详细考察了以水为载流测定的可行性,选择了同时测定As、Hg所需的硼氢化钾浓度和盐酸浓度。方法节省了酸试剂用量,操作快速,单个样品测定仅需20s左右。方法检出限As为0.005 mg/kg,Hg为0.0008 mg/kg,相对标准偏差(RSD%,n=7)在1.0%～7.4%,经土壤国家标准物质和实际样品验证,适合土壤中痕量As、Hg的同时快速测定。     

电感耦合等离子体质谱法测定苎麻不同部位的铬、砷、镉、铅4种重金属元素含量

采用硝酸-双氧水-氢氟酸体系对苎麻不同部位样品进行微波消解,通过智能控温加热器赶酸,利用电感耦合等离子体质谱(ICP-MS)检测苎麻不同部位的铬、砷、镉及铅含量.结果表明:方法操作简便,分析速度快,灵敏度及线性较好,各元素的检出限为~(52)Cr 0.05 mg/kg、~(75)As 0.02 mg/kg、~(111)Cd 0.02 mg/kg、~(208)Pb 0.03 mg/kg,线性范围分别为Cr 0.5~50 mg/kg、As和Cd均为0.1~12.5 mg/kg、Pb 0.2~25 mg/kg.方法精密度和稳定性较好,试验回收率在80.0%~125%之间.初步判断苎麻不同部位4种重金属元素的高低水平,以及苎麻对土壤中的重金属有一定吸附作用.     

电感耦合等离子体质谱法测定苦瓜药材中16种无机元素

建立电感耦合等离子体质谱法测定苦瓜药材中16种无机元素。苦瓜样品采用微波消解处理,电感耦合等离子体原子发射光谱法检测。待测元素的质量浓度在各自的线性范围内与发射光强度线性关系良好,线性相关系数不小于0.999,各元素的检出限在0.001～1.000 mg/kg,定量限在0.003～3.300 mg/kg,回收率在82.9%～112.5%,测定结果的相对标准偏差为0.62%～2.32%。测定样品中的无机常量元素Mg,Ca,Fe,K等含量大于137 mg/kg,有害元素Hg,Pb,Cd,As等含量小于0.5 mg/kg。该方法分析速度快,灵敏度高,适用于苦瓜药材中无机元素测定。     

固相萃取-高效液相色谱法同时检测畜禽粪便中14种兽药抗生素

研究并优化了同时分析畜禽粪便中14种抗生素(四环素、磺胺、氟喹诺酮和大环内酯类)的加速溶剂萃取参数、固相富集净化程序、以及高效液相色谱分离和检测条件。结果表明,以1%乙酸(pH 2.6)作为流动相,在270 nm的检测波长下,14种抗生素能达到基线分离。3倍信噪比下,四环素、磺胺、氟喹诺酮和大环内酯类抗生素的检出限分别为35～90μg/kg,12～28μg/kg,9～17μg/kg及19μg/kg。加标浓度在1和10μg/g时,畜禽粪便样品经过50%甲醇的柠檬酸盐缓冲溶液提取,HLB固相萃取柱富集净化后,四环素、磺胺、氟喹诺酮和大环内酯类抗生素的回收率分别达到了58%～75%和66%～83%,74%～93%和91%～101%,74%～80%和80%～88%,85%和68%,相对标准偏差分别为6.2%～10.7%和7.8%～13.6,2.6%～10.2%和4.4%～13.2%,6.1%～12.5%和8.3%～14.6%,10.6%和12.3%。采用此方法对辽宁省部分规模化养殖场的猪粪、牛粪和鸡粪样品进行了检测。4类抗生素都有检出,浓度范围分别为0.75～22.34 mg/kg,0.10～1.71 mg/kg,0.38～4.46 mg/kg和0.23～0.35 mg/kg。     

电感耦合等离子体发射光谱法测定土壤中钡元素含量

采用微波消解法对土壤样品进行前处理,使用电感耦合等离子体发射光谱(ICP-OES)法测定土壤中的钡元素含量。结果表明,钡元素的质量浓度与特征强度具有良好的线性关系,线性相关系数为0.999 7,检出限为0.5 mg/kg,检出下限为2.0 mg/kg,精密度(相对标准偏差RSD)为0.8%～2.0%,准确度(相对误差RE)为0.1%～2.0%。该方法操作简单,精密度好,准确度高,可用于实际样品的分析。     

压水堆核电站一回路冷却剂系统中硼酸基体对锂含量测定影响的研究

为解决压水堆(PWR)核电站一回路冷却剂系统中硼酸溶液对锂含量测定的影响,对原子吸收法进行了改进。当样品的硼含量小于1000 mg/kg时,使用500 mg/kg硼基体标准工作液,并在样品中加入65 mg/kg的硝酸进行测定;如果样品的硼含量大于1000 mg/kg时,须将样品进行稀释,使稀释后的样品中硼含量小于1000 mg/kg,然后按照硼基体含量小于1000 mg/kg的样品进行测定。测定实际样品L1RCP的精密度为0.48%,回收率为100%,结果证明方法可行。     

全自动流动注射-分光光度法测定土壤中氨氮

传统的氯化钾溶液提取分光光度法测定土壤中氨氮时,需要加入硝普钠-苯酚显色剂混匀后一定时间再加入二氯异氰尿酸钠显色剂,这个过程中人为接触苯酚等有机试剂的时间较长,对人体和环境有一定的危害;且传统的比色法显色时间至少需要5 h,显色时间较长,分析效率较低。应用全自动流动注射-分光光度法测定土壤中氨氮,考察了提取试剂的厂家、浓度等两个因素对实验的影响。采用氯化钾(1.00 mol/L)提取液配制标准曲线,在0～10.00 mg/L线性关系良好,方法检出限为0.031 mg/kg,样品相对偏差均小于5%,实际样品回收率为89.0%～114%。与传统的氯化钾溶液提取分光光度法相比,全自动流动注射-分光光度法具有自动进样、分析速率快,试剂耗量低,检测范围宽、保护环境等优点,适用于一般农用地、场地调查样品中氨氮的检测。     

微波消解-ICP-AES法测定化妆品中8种有毒元素

采用微波消解-电感耦合等离子体发射光谱法(ICP-AES)对化妆品中Ba、Pb、Cd、Sb、Se、Cr、Hg、As8种有毒元素进行同时测定,通过试验确定了仪器参数和各元素的分析线。8种元素的浓度在0～10mg/L均与响应值呈线性关系,相关系数大于0.9995。8种元素测定结果的相对标准偏差均小于10%(n=3),方法检测限小于0.04mg/kg。样品中各元素的加标回收率为82.1%～108.7%。该方法适用于大批量的化妆品检测。     

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。     

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.     

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.     

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。