均相液液萃取-数字成像比色法测定水中痕量六价铬北大核心CSCD

提出了均相液液萃取-数字成像比色法测定水中痕量六价铬的方法。取2.5 mL水样,依次加入0.125 mL十二烷基硫酸钠溶液(20 g·L^(-1))、0.3 mL硫酸溶液(0.5 mol·L^(-1))和0.125 mL含0.04 mol·L^(-1)二苯碳酰二肼的丙酮溶液,摇匀,反应5 min。再用60μL邻苯二甲酸二甲酯和400μL异丙醇的混合液进行萃取,涡旋,离心,通过智能手机比色装置中的Color Grab软件读取萃取层的绿(G)值。结果显示:六价铬标准曲线的线性范围为4~60μg·L^(-1),检出限(3s/k)为1μg·L^(-1);对实际水样进行加标回收试验,本方法所得六价铬测定值与国家标准方法GB 7467-1987的基本一致,回收率为87.8%~109%,测定值的相对标准偏差(n=6)为2.4%~3.7%。     

分散液液微萃取-分光光度法测定食用菌中镉的含量北大核心CSCD

取经清洗、粉碎并烘干的样品0.500 0g,用硝酸5mL及过氧化氢3mL,按程序升温模式微波消解。消解液于沸水浴中蒸发至约1mL,用水定容至50mL。取此溶液5.00mL依次加入0.2g·L^(-1) 5-Br-PADAP溶液2.0mL,氨性缓冲溶液(pH 9.0)3.0mL及100g·L^(-1) Triton X-114溶液3.0mL,加水定容至25mL,摇匀,使Cd^(2+)生成络合物,10min后加入辛醇1.0mL,涡旋混合1min,离心5min,吸出下层溶液,取出上层红色有机层,用乙醇定容至3mL,于540nm处用1cm比色皿测得其吸光度。镉的质量浓度在10.00mg·L^(-1)以内与吸光度呈线性关系,检出限(3s)为0.05mg·L^(-1)。加标回收率为93.3%~103%,测定值的相对标准偏差(n=6)小于5.0%。     

流动注射光度法测定水中总磷量

采用流动注射光度法测定了水中总磷量。水样经硫酸和过硫酸钾在125℃消解后,所得样品溶液中磷(PO_4~(3-))与钼酸铵生成杂多酸,经还原成钼蓝后测定其吸光度。总磷的质量浓度在1.0mg·L~(-1)以内与其吸光度呈线性关系,方法的检出限(3S/N)为0.003mg·L~(-1),测定下限(10S/N)为0.012mg·L~(-1)。方法用于测定水样中总磷的含量,相对标准偏差(n=7)在1.5%～3.0%之间,加标回收率在95.7%～102.5%之间。     

1,2-萘醌-4-磺酸钠为显色剂吸光度差值法测定盐酸普鲁卡因

1,2-萘醌-4-磺酸钠与盐酸普鲁卡因在pH 4.70的条件下反应,产物在300和483 nm处有两个吸收峰,可用两波长下吸光度差值测定盐酸普鲁卡因,本文对吸光度差值与分析物浓度之间的关系作了理论推导。吸光度差值(ΔA)与盐酸普鲁卡因质量浓度在2.0~36.0 mg/L范围内具有良好线性关系,线性回归方程为:ρ=37.092 0ΔA-0.332 3,线性相关系数为0.999 1,相对标准偏差为1.49%,回收率为97%~105%。试验了pH值、放置时间及干扰离子对测定的影响。此法简便、快速、准确,可用于注射液中盐酸普鲁卡因含量的测定,与药典方法对照,结果满意。     

双显色剂双波长分光光度法的研究——Ⅰ.水相中中心离子交换测定微量汞

对Cu(DDTC)_2+Hg~(2+)=Hg(DDTC)_2+Cu~(2+)褪色反应,加入另一种显色剂进行显色反应Cu~(2+)+2BCO=Cu(BCO)_2,在450nm处测量Cu(DDTC)_2吸光度的减少,600nm处测量Cu(BCO)_2吸光度的增加,以两处吸光度差值的和作Hg~(2+)的定量测定,从而建立了测定微量汞的双显色剂双波长分光光度法。该方法的ε=3.7×10~4 L·mol~(-1)·cm~(-1)。检出限为0.14ppm,标准物质检验的相对误差和变异系数分别小于2%和5%。     

气相色谱-质谱法测定乙二醇二缩水甘油醚中环氧氯丙烷的残留量北大核心CSCD

提出了气相色谱-质谱法测定乙二醇二缩水甘油醚中环氧氯丙烷残留量的方法。样品5.000 0 g置于10 mL容量瓶中,用乙醇稀释并定容。所得溶液经超声处理后,采用HP-5MS毛细管柱、载气程序升流和柱程序升温进行气相色谱分离。质谱分析中采用电子轰击离子源和选择离子监测模式。环氧氯丙烷的质量浓度在12.06~602.97 mg·L^(-1)范围内与其峰面积呈线性关系,测定下限(10S/N)为4.21 mg·L^(-1),测定值的相对标准偏差(n=8)为0.51%。按标准加入法进行回收试验,回收率在94.2%~97.1%之间。     

双波长分光光度法同时测定矿石中钛和铁

本文试验了直接使钛和铁与二氨替比林甲烷同时显色,利用等吸收点法,在本文的试验条件下,于λ_1=388nm及λ_2=513nm处测定两个波长的吸光度,并以A_(388nm)-A_(513nm)求出两个吸光度差值(△A),即为钛的结果。铁的测定可以用两个方法:一个是在波长560nm处直接测定     

微波消解-石墨炉原子吸收光谱法测定固定污染源废气样品中铜、镍、镉的含量北大核心CSCD

用滤筒采集固定污染源废气样品,将滤筒剪碎,置于微波消解管中,加入体积比3∶1的盐酸-硝酸混合液5.0 mL和水20.0 mL,于200℃消解15 min.在所得消解液中加入水10 mL,静置0.5 h进行浸提,过滤,用水定容至50 mL.所得样品溶液采用石墨炉原子吸收光谱法测定其中铜、镍、镉的含量.铜、镍、镉3种元素优化的测定条件如下:灰化温度依次为1100,1200,500℃,灰化时间均为20 s,原子化温度依次为2000,2400,1500℃,原子化时间依次为5,5,4 s.结果表明:铜、镍、镉的质量浓度在一定范围内与其对应的吸光度值呈线性关系,检出限(3.143s)依次为2,3,0.06μg·L^(-1).用此法测定煤飞灰中重金属成分分析标准物质(总量)(RMU010),测定值与认定值基本一致.平行测定某实际煤飞灰样品6次,测定值的相对标准偏差为2.6%~7.0%.采集某固定污染源废气样品7个,按本方法测定,测定值的相对标准偏差小于20%,说明采集方法具有一定稳定性.     

四酸消解-氢化物发生原子荧光光谱法测定地球化学样品中全硒的含量北大核心CSCD

称取0.250 0 g样品,以2.5 mL盐酸、2.5 mL硝酸、2.5 mL氢氟酸和5 mL高氯酸为酸体系,设置消解温度为110~150℃;消解结束后,趁热加入盐酸(还原剂) 5 mL和10 g·L^(-1)三氯化铁溶液(掩蔽剂) 5 mL,再用水稀释至25 mL,得到待测样品溶液,采用氢化物发生原子荧光光谱法测定其中全硒的含量。结果显示:硒的质量浓度在20.00μg·L^(-1)以内与其对应的响应值呈线性关系,检出限(3s/k)为0.06μg·L^(-1);对岩石、土壤和水系沉积物国家标准物质进行验证,测定值的相对标准偏差(n=6)为0.68%~2.5%,回收率为94.0%~110%。     

不过滤水样中铁离子的反射吸光光度法研究

自制了与商品化吸光光度计匹配的反射吸光度测定装置,并利用该装置研究了水样浊度对铁(Ⅱ)-邻菲罗啉络合物反射吸光度的影响。实验结果表明,当铁离子质量浓度在0~10.00 mg/L范围内时,具有一定浊度(T)的试样按标准方法显色后,试样浊度的反射吸光度(AT)与铁(Ⅱ)-邻菲罗啉络合物的反射吸光度具有加和性。通过大量实验数据,推导出AT=4.49×10~(-4)T+0.0264(R~2=0.9774,n=20)。基于此,建立了不过滤水样中铁离子的反射吸光光度法,即:水样无需过滤,按标准方法加入试剂显色,测得吸光度AS;同时,用以上推导公式计算AT;以AS-AT代入标准曲线方程即可计算待测水样中的铁离子质量浓度。采集4个实际河水水样为基底,随机加入适量铁离子标准溶液,分别用本论文研究的方法和标准方法测定水样中的铁离子质量浓度,两者的测定结果无显著差异。     

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。