蜂蜜中葡萄糖、果糖和木糖的多元校正定量分析研究

根据单糖与邻甲苯胺加成缩合反应的显色特征,采用偏最小二乘法(PLS)辅助分光光度法对吸收光谱重叠较严重、加和性欠佳的葡萄糖、果糖和木糖三组分的模拟混合试样进行分析,对同时测定的条件进行了优化,建立了单糖多组分体系同时定量分析的多元校正方法,并用此方法对蜂蜜样品中上述单糖组分的含量进行了测定.时模拟混合试样,回收率分别为...     

正交投影分光光度法同时测定联磺甲氧苄啶片中的SMZ和TMP

采用正交投影分光光度法同时测定3组分复方药物联磺甲氧苄啶片中磺胺甲恶唑(SMZ)和甲氧苄啶(TMP)二组分的含量。SMZ和TMP的平均回收率分别为99，6％和99．4％，测定结果的相对标准差分别为0，75％和0．60％。讨论了波长区间和波长间隔对测定结果的影响。     

共沉淀分离富集偏最小二乘法在茶叶重金属测定中的应用

以铜试剂为共沉淀剂,在pH值为10.0的条件下,共沉淀分离富集茶叶中痕量金属离子Ni^(2+)、Pb^(2+)、Cd^(2+)和Cu^(2+),并分析了铜试剂与金属离子形成配合物的最佳沉淀条件.用4-(2-吡啶偶氮)间苯二酚(PAR)作为这4种重金属离子的显色剂进行分光光度测定,采用偏最小二乘-紫外可见光度法同时测定了四组分金属离子的模拟混合试样,并在茶叶中进行上述金属离子含量的测定.方法操作简便、结果可靠,对茶叶中重金属测定有一定实用价值.     

统计模拟分光光度法在增效联磺片分析中应用的研究

本文应用统计模拟分光光度法建立了同时测定增效联磺片三组分含量的分析方法。用全面交叉组合法安排实验，获得有限但足够的实验数据，再用逐步回归法构造在不同波长下吸光度与组分浓度经验关系的“最优”数学模型，用全组合检索法寻优求出未知样品诸组分的含量。为认证此方法用均匀设计安排回收率试验，并对含量测定结果进行了方差分析，结果均令人满意．     

卡尔曼滤波分光光度法用于多组分芳香类化合物的同时测定

本文用卡尔曼滤波分光光度法分析了2～4组分芳香类化合物模拟混合试样,实现了多组分的同时测定。被测组分的回收率在100±10%以内(被测组分的浓度范围为0～5×10~(-6))。本文还对滤波的波长范围和波长间隔对计算结果的影响也进行了初步的探讨,并把此法的计算结果和目标因子分析(TFA),偏最小二乘法(PLS)的计算结果进行了比较。     

线性规划—导数分光光度法同时测定钴,镍,铜,锌,铁的研究

1 引言 近年来,随着计算机的普及和发展,用化学计量学方法来解析光谱数据,实现毋需分离的多组分同时测定的报道迅速增加,但一般仅限于用来解析基本光谱数据。本文提出用线性规划算法解析一阶导数光谱数据的新方法,对以PAR为显色剂的Co、Ni、Cu、Zn、Fe五组分混合体系的同时测定进行了研究,结果表明,该法既保持了导数分光光度法的高灵敏度,又利用了线性规划算法解决了普通导数光谱难以解析的5组分同时测定问题,对标准合成样品进行了测定,结果令人满意。     

自适应卡尔曼滤波分光光度法同时测定撒痛风注射液中各组分的含量

本文应用自适应卡尔曼滤波分光光度法同时测定了撒痛风注射液中各组分的含量,水杨酸钠、咖啡因、安替比林三组分平均回收率均为100.0％,相对标准偏差(％)依次为0.57、0.61和0.75,结果优于常规卡尔曼滤波法。自适应卡尔曼滤波法为不经分离直接测定相互干扰的多组分体系分析提供了一种新的途径。     

主成分回归用于分光光度法同时测定6种食品添加剂

山梨酸、苯甲酸钠、香兰素、NaNO2、NaNO3和糖精钠的紫外吸收光谱严重重叠,不经预先分离很难进行单一组分的直接测定.报道了一种同时测定上述6种食品添加剂的分光光度法,这种方法是基于在pH 2.85的Britton-Robinson(B-R)缓冲溶液中对该6种食品添加剂混合溶液进行光度测定,所得的重叠光谱数据用主成分回归(PCR)进行建模,并用该模型对未知样品浓度进行预报.该方法可以不经分离同时测定食品样品中的多种添加剂.     

分光光度法同时测定复方新诺明制剂中磺胺甲(口恶)唑及甲氧苄氨嘧啶的含量

1引言 对于相互干扰的两组分析体系的分光光度法测定,已有许多方法.我们以解联立方程组结合标准曲线法或线性回归法测定二元体系,方法简便、结果准确,既可测定其中的单个组分,也可同时测定两组分.对复方新诺明制剂中磺胺甲()唑(SMZ)和甲氧苄氨嘧啶(TMP)测定的结果与标准方法一致.     

分光光度法同时测定石油制品中铁镍钒及钴的含量——小波变换-LSSVM算法的应用

石油产品样品经燃烧和灼烧除去碳氢化合物后,用稀盐酸溶解残渣,分取部分样品溶液用5-Br-PADAP作显色剂,对其中铁、镍、钒、钴的含量进行分光光度法同时测定.用试剂空白作参比溶液,在540～620 nm波长范围内每隔2 nm测定一次吸光度.所得数据用小波变换法处理以滤去分析信号中的噪声,然后用最小二乘支持向量机(LSSVM)算法解析所得分析数据.结果表明:LSSVM算法具有计算速度快,结果准确及泛化性能好等特点.用模拟样品对LSSVM算法进行预测,测得上述4元素的回收率在96.0%～103.5%之间.应用于分析实样时,所测得4元素结果与原子吸收光谱法的测得结果一致,所得结果的相对标准偏差(n=8)均小于4%.     

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.     

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。     

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.     

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.     

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...