双波长双指示剂催化动力学光度法测定食品中的痕量铜

在pH=9.65的NH3-NH4Cl缓冲溶液中,利用Cu2+对H2O2氧化中性红和溴甲酚紫褪色反应具有较强的催化作用,通过测量460nm和590nm波长下催化体系和非催化体系的吸光度,建立了双指示剂、双波长催化动力学光度法测定痕量Cu2+的新方法。方法的线性范围为0.0060～0.072μg/mL,检出限为8.0×10-12g/mL。对Cu2+进行11次平行测定的相对标准偏差为2.9%。方法用于面粉和大米中痕量铜的测定,结果令人满意。     

双波长双指示剂催化光度法测定痕量Mn(Ⅱ)

在硫酸介质中,以氨三乙酸为活化剂,利用痕量Mn(Ⅱ)催化高碘酸钾氧化灿烂绿和酸性铬蓝K褪色的指示反应,分别在430nm和630nm波长下测量催化体系和非催化体系的吸光度,建立了双指示剂双波长催化动力学光度法测定痕量Mn(Ⅱ)的新方法。在优化条件下,测定Mn(Ⅱ)的线性范围为0.00200～0.0300μg/mL,检出限为1.2×10-11 g/mL。方法可用于茶叶和废水中痕量锰的测定。     

溴酸钾氧化孔雀石绿和甲基橙褪色光度法测定水中亚硝酸根

在H3PO4介质中,利用痕量NO2-催化KBrO3氧化孔雀石绿和甲基橙褪色的反应,建立了双波长双指示剂催化动力学光度法测定痕量NO2-的新方法。该反应在最大吸收峰505nm和615nm处,催化和非催化体系吸光度的变化与NO2-浓度呈线性关系,线性范围为0.01～0.80μg/mL,检出限为1.3×10-3μg/mL,该方法用于环境水样(自来水、雨水、延安卷烟厂废水)中痕量NO2-的测定,加标回收率为97%～110.2%.     

双波长双指示剂催化光度法测定铜的研究

研究了在pH 4.0的HAc～NaAc缓冲介质中,利用痕量铜(Ⅱ)催化过氧化氢氧化罗丹明B和亚甲基蓝褪色的指示反应,通过测量540 nm和660 nm下,催化体系和非催化体系吸光度的变化,建立了双波长双指示剂催化动力学光度法测定痕量铜的新方法.方法的线性范围为0.00080～0.048μg/mL,检出限为4.0×10~(-11) g/mL.方法可用于水中铜的测定.     

微波消解-双指示剂和双波长催化分光光度法测定化妆品中痕量铬(Ⅵ)

稀H2SO4介质中,痕量铬(Ⅵ)对氯酸钾氧化甲基绿和结晶紫褪色的反应有较强的催化作用,通过测量550nm和620nm波长下非催化体系和催化体系吸光度的变化,计算△A值,建立了双指示剂双波长动力学光度分析法测定化妆品中痕量铬(Ⅵ)的方法。结果表明,方法线性范围为0.045～0.200μg/mL,检出限为0.003μg/mL,回收率在98.0%～101.2%之间,相对标准偏差小于2.6%。方法简便快速。     

微波消解-双波长双指示剂动力学光度法测定人发中的痕量铁

研究了微波消解人发的最佳条件,同时研究了在HNO3介质中,痕量铁(Ⅲ)催化H2O2氧化甲基紫和亚甲基蓝褪色的指反应,建立了双波长双指示剂催化动力学光度法测定痕量铁的新方法。方法的线性范围为0.005~0.05μg/mL,检出限为1.02×10-4μg/mL。该方法可用于人发中痕量铁的测定。     

双波长双指示剂-催化动力学光度法测定奶粉中的锌

研究发现在HCl介质中,痕量锌对H2O2氧化甲基紫和亚甲基蓝褪色具有强烈的催化作用,通过测量580 nm和668 nm处催化反应体系和非催化反应体系吸光度的变化,建立了双波长双指示剂催化动力学光度法测定痕量锌的新方法。在最佳实验条件下,线性范围为1.5~60μg/L,线性方程为ΔA=0.0169ρZn2+(μg/mL)+0.0019,r=0.9982,方法检出限为0.84μg/L。该方法可用于奶粉痕量锌的测定。     

甲基橙-亮绿体系动力学光度法测定茶叶中痕量铁

在硫酸介质中,Fe(Ⅲ)对过氧化氢氧化甲基橙和亮绿褪色反应具有强烈的催化作用,通过测定510 nm和640 nm波长下催化体系和非催化体系的吸光度,建立了双波长双指示剂催化动力学光度法测定痕量Fe(Ⅲ)的新方法。最佳实验条件下,测定的线性范围为8.0~200μg/L,检出限为1.12×10-10g/L。对20.0μg/L Fe(Ⅲ)进行12次平行测定的相对标准偏差为0.067%。该方法灵敏度高,体系稳定,具有较好的选择性,用于茶叶中痕量铁的测定,结果满意。     

双波长双指示剂催化光度法测定食品中痕量钒

研究了在0.2 mol/L柠檬酸介质中,利用钒酸根对溴酸钾氧化乙基紫和萘酚绿B褪色反应同时具有强烈的催化作用,通过650 nm和720 nm波长下测量催化体系和非催化体系的吸光度,建立了一种双指示剂、双波长催化动力学光度法测定钒(V)的新方法。最佳实验条件下,测定钒的线性范围为1.00~80.0μg/L,检出限为1.1×10-10g/mL。对20.0μg/L钒进行12次平行测定的相对标准偏差为2.2%。方法用于面粉和大米中痕量钒的测定,结果令人满意。     

双波长催化光度法测定痕量亚硝酸根

研究了在稀硫酸介质中,痕量亚硝酸根对溴酸钾氧化溴甲酚绿和甲酚红褪色的指示反应,通过测量440 nm和520 nm波长处催化反应体系和非催化反应体系吸光度的变化,建立了双波长双指示剂催化动力学光度法测定痕量亚硝酸根的新方法。在最佳实验条件下,亚硝酸根的浓度在0.008~0.120μg/mL之间与吸光度存在线性关系(r=0.9968),方法检出限为0.0022μg/mL。该方法简单,灵敏度高,选择性好,用于实际样品中痕量亚硝酸根的测定,获得满意结果。     

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。     

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.     

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。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...