微波消解-ICP-OES法测定汽车涂料中8种重金属

建立微波消解-电感耦合等离子体发射光谱(ICP-OES)测定汽车涂料中Pb,Cr,Se,Ba,Sb,As,Cd,Hg含量的方法。以HNO_3-H_2O_2(体积比为4∶1)混合酸消解样品,各元素分析谱线:Pb 220.353 nm,Cr 267.716 nm,Se196.090 nm,Ba 233.527 nm,Sb 217.581 nm,As 189.042 nm,Cd 228.802 nm,Hg 184.950 nm。8种元素测定结果的相对标准偏差为2.02%~12.94%(n=6);对白色、蓝色、红色汽车漆样品进行加标回收试验,Pb,Cr,Se,Ba,As,Cd,Hg,的加标回收率为81.26%~99.79%,Sb的回收率为62.43%~87.61%。该方法快速、简便,精密度、准确度较高,可用于汽车涂料中重金属含量的监控。     

电感耦合等离子体质谱法测定环境评价性土壤中铬铜镉铅

针对环境评价性土壤,采用HNO_3-HClO_4-HF消解样品、HNO_3提取技术,以52Cr、65Cu、114Cd、208Pb作为测定同位素,采用间接经验公式校正质谱干扰,最终实现了电感耦合等离子体质谱法(ICP-MS)同时对Cr、Cu、Cd、Pb等4种重金属的测定。详细对比分析了HCl-HNO_3-HClO_4-HF、HCl-HNO_3-H_2SO_4-HF、HNO_3-HClO_4-HF消解法等3种试样处理方法对土壤成分分析标准物质的分析数据,结果表明:HNO_3-HClO_4-HF消解法测定值与认定值相符。Cr、Cu、Cd、Pb的校准曲线相关系数均达0.9999以上,方法测定限(μg·L~(-1))分别为:Cr1.54,Cu 0.83,Cd 0.024,Pb 0.29。将方法应用于土壤4种重金属元素的测定,结果与认定值基本一致,相对标准偏差(RSD,n=12)均小于8%,加标回收率在96.7%~102.3%。方法应用于实际环境评价性土壤样品分析,结果与X射线荧光光谱法(XRF)相吻合。     

电感耦合等离子体发射光谱法测定纺织品中总硼

建立了微波消解-电感耦合等离子体发射光谱法(ICP-OES)测定纺织品中总硼的分析方法。纺织样品经HNO_3-H_2O_2微波消解,以钇元素作为内标元素,以249.772nm波长作为硼的分析线,采用ICP-OES法进行测定。实验结果表明,硼的质量浓度在0.01~0.20mg/L范围内与发射强度比值呈线性关系,方法的定量限为0.8mg/kg,在0.8、1.6、8.0mg/kg添加水平下的回收率为80.4%~104.7%,相对标准偏差为2.4%~9.8%。该方法灵敏度高,定量准确可靠,能够满足纺织品中总硼含量的检测要求。     

微波消解/ICP-MS同时测定粮食、蔬菜中的11种重金属元素

建立了微波消解/电感耦合等离子体质谱法同时测定粮食和蔬菜中11种重金属元素(Cu、Mn、Cr、Pb、Cd、Ni、Sb、Hg、Co、Ag、As)的方法,优化了微波消解条件和仪器测定条件,采用HNO_3-HF-H_2O_2和HNO_3-H_2O_2两种混酸体系,将样品进行完全消解。结果显示,11种金属元素的线性系数不小于0.999 5,方法的检出限为0.001~10.00μg/L,测定的相对标准偏差(RSD,n=5)不大于5.0%。该方法具有快速、简便、灵敏度高、稳定性好、准确度高等优点。     

微波消解–ICP–AES法测定罗布麻叶中16种微量元素

建立微波消解–ICP–AES法测定罗布麻叶中Na,Ca,Mg,Fe,Al,P,Mn,Ni,Cu,Zn,Ti,Se,Ba,Pb,Sr,Cd 16种微量元素含量的方法。以HNO_3–H_2O_2–HF溶液(6∶4∶1)为消解体系,样品经微波消解后,用ICP–AES法对罗布麻叶中16种元素含量进行测定。各元素的质量浓度在0.01~1.00 mg/L范围内与光谱强度呈良好的线性关系,线性相关系数r>0.999,检出限在0.000 5~0.008 0 mg/kg之间。加标回收率为87.56%~101.47%,测定结果的相对标准偏差为1.2%~3.42%(n=6)。该方法操作简单,准确度好,灵敏度高,可用于罗布麻叶中微量元素分析。     

氢化物发生-原子荧光光谱法测定铀矿石中的锗元素

建立了氢化物发生-原子荧光光谱法测定铀矿石中锗元素的方法,使用HNO_3-HF-H_2SO_4-H_3PO_4混酸体系消解样品,对铀矿石中的微量Ge元素进行分析,方法检出限为0.024μg/g,样品相对标准偏差(RSD)为3.4%。通过与标准值比对,结果准确度令人满意,未知样品加标回收率在98.4%~103%。可以作为实验室日常分析含铀矿石中微量Ge元素的参考方法。     

电感耦合等离子体质谱法测定土壤中痕量铊的方法研究

采用电感耦合等离子质谱法(ICP-MS)测定土壤中的痕量铊,并对前处理方法进行研究,建立了一种使用HNO_3-H_2O_2-HF酸消解体系测量土壤中痕量铊的方法。该方法在0.00~5.00μg/L范围内线性良好,相关系数为0.999 8,方法检出限为0.1 ng/kg,对4份铊土壤标准样品测定的结果均在保证值范围内,RSD为1.8%~6.6%,2份土壤实际样品的加标回收率为95.4%~102.4%。     

微波消解-电感耦合等离子体质谱法同时测定化妆品中的汞、铅、砷、锑

采用HNO_3-H_2O_2微波消解样品,电感耦合等离子体质谱法(ICP-MS)同时测定化妆品中的汞、铅、砷、锑.实验中探讨了最佳的消解程序,选择适当的同位素,并用铋、铟、锗做内标元素,有效地抑制了分析信号的漂移.结果表明,各元素的检出限在0.089～0.37μg/kg,相对标准偏差(RSD)在0.709%～2.10%,回收率为80.10%～102.67%.该方法具有简便、快速、准确、灵敏度高的优点,适用于化妆品中的汞、铅、砷、锑元素的同时测定.     

微波消解-电感耦合等离子体发射光谱(ICP-OES)法测定茄子中矿物元素含量

采用微波消解HNO_3+H_2O_2湿法制取样品溶液,全谱直读电感耦合等离子体发射光谱(ICPOES)法同时测定茄子中K、Na、Mg、Al、Ca、B、Ba、Cr、Cu、Fe、Sn、Mn、P、Sr、Zn 15种矿物元素,实际样品测定结果显示,Al元素含量超过国家规定标准(≤100mg/kg),微量元素Ca含量相对较高。各元素的检出限为1.0~440μg/L,标准样品的加标回收率93.5%~109%,相对标准偏差在2.1%~6.5%(n=6)。实验方法简单、重现性好,可用于测定茄子样品中各矿物元素含量。测定结果为茄子的深入研究提供基础数据。     

微波消解-ICP-MS测定皮革中7种重金属元素

建立了微波消解法消解皮革样品,ICP-MS同时测定皮革中的Co,Ni,Cu,Cd,Sb,Hg,Pb 7种微量元素的方法。通过优化微波消解条件、ICP-M S各项参数以及选用~(45)Sc,~(72)Ge,~(115)In,~(209)Bi元素为内标混合液校正基体效应和信号漂移,测得皮革中的7种微量元素的检出限在0.57~2.43μg/L之间,7种元素在25~125μg/L范围内呈现良好的线性关系,线性相关系数均大于0.9999,样品加标回收率在95.5%~106.3%之间,相对标准偏差(n=10)在0.6%~2.2%之间。     

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.