氢化物发生-原子吸收光谱法测定锑(Ⅲ)和锑(Ⅴ)

提出在酸性条件下以氟化钠为掩蔽剂测定锑(Ⅲ),在碱性介质中加入氟化钠消除价态的影响测定锑总量,两者相减求出锑(Ⅴ),实现对锑(Ⅲ)和锑(Ⅴ)的分别测定.研究了在酸性介质中测定锑(Ⅲ)及碱性介质中测定锑总量的条件及共存离子的干扰和消除.工作曲线的线性范围为：0～20 μg·L-1锑(Ⅲ);0～80 μg·L-1锑(Ⅴ),相关系数大于0.999,方法的检出限为0.31 μg·L-1锑(Ⅲ),0.69 μg·L-1锑(Ⅴ).对水样和土壤样品进行了测定,相对标准偏差(RSD)小于5%.     

氢化物发生-原子荧光光谱法同时测定陈皮中砷和汞

采用微波消解法消解陈皮样品,利用氢化物发生-原子荧光光谱法同时测定陈皮中砷和汞.研究并优化了硼氢化钾的用量、消解介质的酸度、共存离子的干扰和消除等试验条件.荧光强度与砷及汞的质量浓度在20.0μg·L-1及2.00 μg·L-1以内呈线性关系,方法的检出限为0.084μg·L-1(砷)和0.022 μg·L-1(汞).应用此法分析了6个陈皮试样,测定值的相对标准偏差均小于7.0%,以标准加入法做回收率试验,平均回收率分别为93.6%(砷)和90.7%(汞).     

微波消解样品-蒸气发生-原子荧光光谱法测定石脑油中砷和汞

提出了微波消解样品-蒸气发生-原子荧光光谱法测定石脑油中砷和汞的方法.采用微波消解法处理样品,优化了微波消解条件和仪器工作条件,解决了消解液中过剩酸对测定的干扰.砷、汞的检出限分别为0.11,0.045 μg·L-1;线性范围分别在1.0～100.0,0.5～50.0 μg·L-1之间,砷和汞的相对标准偏差均小于4%,回收率分别在95.2%～97.2%,92.9%～95.2%之间.     

微波消解-氢化物发生-原子荧光光谱法同时测定土壤及生物样品中铅和汞

应用氢化物发生-原子荧光光谱法测定了土壤及生物样品中铅和汞。样品用硝酸4mL及过氧化氢1mL按微波消解仪的工作参数进行消解,消解后溶液定容至25mL供测定。用30g·L-1柠檬酸溶液和硝酸(1+99)溶液的混合液作载流,根据铅(Ⅱ)离子的反应和试液对酸度的要求,选用含15g·L-1硼氢化钾,10g·L-1铁氰化钾和20g·L-1氢氧化钾的混合溶液作为还原剂。方法的检出限(3s/k)为0.512μg·L-1(铅)和0.067μg·L-1(汞)。应用此方法分析了3种实样并进行加标回收试验,测得回收率分别在91.0%~97.0%(铅)和88.0%~95.5%(汞)之间。     

土壤中锑的双阳极电化学氢化物发生-原子荧光光谱法测定

采用双阳极电化学氢化物发生与原子荧光在线联用测定土壤中的锑含量,其中氢化物发生通过以纯铅为阴极,2根钛丝作阳极的双阳极电解池实现.对电解池工作条件及原子荧光参数进行了优化,最佳工作条件为以0.5 mol·L-1硫酸作电解液,流速2.0 mL·min-1,阴极电解电流密度0.5 A·cm-2.同时以去离子水为进样载流,流速设定为1.5 mL· min-1,六通阀进样100 μL得到方法检出限为0.91 μg· L-1 (S/N＝3);相对标准偏差(RSD)为1.58% (50 μg·L-1,n＝11);线性范围为1 ～300 μg·L-1.     

氢化物发生-原子荧光法测定鹿系列保健品中铅

采用 HNO,3-HClO,4 消解样品,氢化物发生-原子荧光法测定鹿系列保健品中铅.该方法在选定的操作条件下,测定保健品中铅的回收率为 91.0%～108.1%,检出限为 0.395 μg·L-1,相对标准偏差为 1.2%.     

ICP-AES测定铀污染土壤植物中铀的研究

采用电感耦合等离子体发射光谱(ICP-AES)对铀污染土壤植物中铀的测定方法进行了研究.在λU385.958 nm处,选择了仪器的最佳工作条件,考察了酸度和常见共存元素对测定的干扰情况,并且对比了干灰化消解和湿式消解对测定的影响.研究发现2%硝酸溶液为最佳介质,干扰离子对测定没有显著影响,干灰化消解比湿式消解得彻底.在选定条件下,方法检出限为0.18 mg·L-1,测定下限为0.61 mg·L-1,5.0000 mg·L-1的铀标准溶液的相对标准偏差RSD(n=10)为0.81%,方法回收率为96.2%～106.2%.该方法操作简单,快速.结果表明,用ICP-AES测定铀污染土壤植物样品中的铀是可行的.     

气相色谱法测定工业废水中挥发酚

提出了工业废水样品中的挥发性酚经预先用溴衍生化后用环己烷萃取分离,分取部分萃取液作气相色谱分析的方法.用此方法测定了苯酚、邻甲酚、间甲酚及对甲酚4种挥发酚,所测得的线性范围分别为0.008～80μg·L-1,0.010～100 μg·L-1,0.018～100 μg·L-1,0.012～100 μg·L-1,检出限(S/N=3)分别为8.4 ng·L-1,10.6 ng·L-1,19 ng·L-1,12.8 ng·L-1,测得其回收率在87%～91%之间,相对标准偏差(n=6)在4.0%～7.0%之间.     

氢化物-原子荧光光谱法测定高纯铅中微量锑

研究了高纯铅中微量锑的氢化物-原子荧光光谱方法。考察了最佳测定条件、干扰的消除方法及酸度影响。结果表明,采用硝酸溶解样品,蒸至有硝酸铅析出后,加入盐酸酸度达20%时,基体铅以氯化铅形式沉淀,消除基体铅的影响,其它共存离子不干扰锑的测定。检出限(3σ)为0.37μg.L-1,样品加标回收率在95.0%~101.4%之间,RSD为1.73%。     

电感耦合等离子体原子发射光谱法测定铅锑合金中锑

采用电感耦合等离子体原子发射光谱法对铅锑合金中锑含量进行测定。样品经硝酸(1+1)溶液和200 g.L-1酒石酸溶液溶解,选择206.833 nm的谱线作为测定锑的分析线。锑的质量浓度在5.0~100.0 mg.L-1之间与其谱线强度呈线性关系。测定下限(10S/N)为0.179 mg.L-1。在优化的试验条件下,分析了两种铅锑合金样品,加标回收率分别为97.8%及98.6%,相对标准偏差(n=11)小于1.5%。     

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。     

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.     

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.