测定润滑油添加剂中钙钡的乳浊液进样-火焰原子发射光谱法

将乳浊液进样技术应用于火焰原子发射光谱法 ,建立了测定润滑油添加剂中钙和钡的灵敏、快速分析方法。对乳化剂的选择、化学干扰的消除、空白溶液的选择及检出限进行了考察。将样品的苯溶液用乳化剂OP乳化成乳浊液 ,取适量样品乳浊液加入适量琼脂溶液及释放剂配制成试液 ,喷入火焰 ,用标准加入法测定。该法的测定结果与灰化 -火焰原子发射光谱法一致 ,相对误差小于±2.9 %,t检验表明两种方法之间无显著性差异。方法的相对标准偏差小于2.7%,检出限:钙0.12mg/L、钡0.99mg/L。     

微波消解-微波等离子体矩原子发射光谱法测定乳胶管中的铁、钙、镍、镁、锌

本文研究了用HNO3-H2O2微波消解样品,微波等离子体矩原子发射光谱(MPT-AES)测定乳胶管中铁,钙,镍,镁,锌的含量方法。详细考察了测定铁、钙、镍、镁、锌的最佳实验条件,以及介质酸、共存离子的影响。本方法测定铁、镍、镁、钙、锌的检出限分别为77.80、7.55、2.70、275.87、46.23 ng/mL,方法的精密度分别为3.10%、2.19%、2.22%、1.27%、2.90%,线性范围分别为0.08~2 mg/L0、.06~2 mg/L0、.001~3 mg/L、0.005~2 mg/L、0.05~1 mg/L,加标回收率分别在97.7%~107.8%、96.0%~106.7%、98.0%~106.2%、92.3%~108.8%、98.7%~106.8%范围。     

火焰原子吸收法测定乳酸钙奶中钙含量

采用火焰原子吸收法测定了乳酸钙奶中钙的含量，方法灵敏、准确、操作简便。线性范围为0－10mg/L，回收率为91．0％－98．0％，相对标准偏差低于4．0％。     

微量进样火焰原子吸收光谱法对牛奶中钙的直接测定

采用微量进样火焰原子吸收光谱法（FAAS）直接测定牛奶中的钙,无需样品预处理。该法与消化后常规FAAS法的测定结果一致。钙质量浓度在0～20 mg/L范围内与吸光度呈线性关系,检出限（S/N=3）为0.013 mg/L,加标回收率为98%～101%,相对标准偏差（n=6）小于2%。方法应用于实际样品的测定,结果令人满意。     

阳离子交换树脂在线富集／火焰原子发射光谱法直接测定健康人尿中锂的研究

采用732磺酸型阳离子交换树脂在线富集、4mol／L HCl洗脱，直接进样火焰原子发射光谱法测定健康人尿中的痕量锂。方法可消除尿中大量有机物的干扰，富集5．0mL标准试液比直接测定信号增大3．5倍，绝对检出限达7．5ng。标准加入法5次测定尿样的RSD为4．7％。     

火焰中锂原子的激光增强电离光谱研究

报导了对火焰中锂原子的激光增强电离光谱(LEIS)行为的研究.利用锂原子的2³P_1/2,3/2→3²D_3/2,5/2激发过程,对改变激光通过火焰位置、乙炔流量、阴极电压、溶液酸度和钾、钠存在时对锂原子的激光增强电离光谱的影响,进行了实验和初步探讨.     

电感耦合等离子发射光谱法测定降水中钾、钠、钙、镁

目前测定降水中钾、钠、钙、镁的常用方法主要有火焰原子吸收法、火焰原子发射法和离子色谱法[1]。用火焰原子吸收法测定钾、钠易产生较大的电离干扰,需加入消电离剂,测定钙、镁需加入释放剂,两法操作都较繁琐。对于钾钠浓度大于0.5mg/L的样品在不稀释的情况下必须降低仪器的灵     

空气-乙炔火焰原子吸收法测定钨酸铵中微量钙和镁

钨制品中微量钙和镁的测定多数采用发射光谱法,也有用原子吸收法测定钨精矿中钙和三氧化钨中镁,用分光光度法往往需要分离富集,操作繁琐。本文建立了用空气-乙炔火焰原子吸收法测定钨酸铵中镁和钙的灵敏而简便的方法。研究了钨对钙的干扰机理及其消除方法,采用2mg/ml锶作为干扰抑制剂,消除共存离子的干扰,所拟定的方法用于样品分析获得满意结果。实验部分     

电感耦合等离子体原子发射光谱法同时测定不锈钢中的11种元素

建立电感耦合等离子体原子发射光谱法同时测定不锈钢中硅、锰、磷、铬、镍、钼、钴、钒、钛、铜、铝11种元素含量的方法。样品采用盐酸溶液溶解,硝酸氧化,在优化的实验条件下,用电感耦合等离子体原子发射光谱法测定各元素含量。磷的质量浓度在0～5 mg/L范围内,钛、铝、钴的质量浓度在0～10 mg/L范围内,钒的质量浓度在0～15mg/L范围内,铜、硅、钼的质量浓度在0～20 mg/L范围内,锰的质量浓度在0～50 mg/L范围内,镍的质量浓度在0～80 mg/L范围内,铬的质量浓度在0～100 mg/L范围内与光谱强度呈良好的线性关系,相关系数均大于0.998,方法检出限为0.002～0.035 mg/L。测定结果的相对标准偏差均小于2%(n=6),加标回收率为97.9%～105.6%.该方法快速、准确,适用于实际生产中不锈钢样品的批量检测。     

火焰原子发射光谱法测定电解铝中痕量钾

建立了火焰原子发射光谱法检测电解铝中痕量钾的方法。用稀王水(1:1,V/V)边加热边溶解电解铝样品,冷却后转移到100 m L容量瓶,待用;为消除铝基体干扰,标准工作溶液需加入适量的铝,火焰原子发射光谱法直接测定。方法线性范围为0.010~0.120μg/m L,检出限(3σ)为0.4 ng/m L(n=11),连续9次测定0.040μg/m L钾标准工作溶液,其RSD为0.72%。分析了3种电解铝样品中钾含量,回收率范围为90.0%~100.0%。该方法可用于电解铝样品中痕量钾的检测。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.