微波消解-电感耦合等离子体质谱法测定鲤鱼、河蚌样品中的铜、镉、铅、铬

建立微波消解–电感耦合等离子体质谱法同时测定鲤鱼、河蚌样品中铜、镉、铅、铬4种重金属元素的含量。以20.0μg/L的Rh作为内标,采用硝酸–过氧化氢消解液,用微波消解仪消解鲤鱼、河蚌等生物样品,在选定的仪器工作条件下测定。铜、镉、铅、铬4种重金属元素的质量浓度在1～100μg/L范围内与其质谱强度呈良好的线性关系,相关系数均为0.999 9,方法检出限为0.01～0.09μg/L。测定结果的相对标准偏差为1.30%～9.95%(n=6),样品加标回收率为91.0%～111%。用所建方法对黄鱼国家标准物质(GBW 08573)进行测定,测定值与标准值基本一致,相对误差均小于7%。该方法简单、快速,灵敏度高,重现性好,适用于大批量生物样品中多种重金属元素的同时测定。     

氢化物发生–原子荧光法测定水中的镉

采用氢化物发生–原子荧光光谱法对水中的镉进行测定。在0.24 mol/L盐酸介质中,以1.2 mol/L钴溶液为信号改进剂、2 g/L磺基水杨酸钠为基体改进剂,镉与硼氢化钾(质量浓度为25 g/L)反应生成镉的挥发性物质。镉的质量浓度在0~5μg/L范围内与荧光强度呈良好的线性,线性相关系数r=0.999 7,方法检出限为0.021 5μg/L,测定结果的相对标准偏差为1.89%(n=7),加标回收率为88.0%~113.2%。该方法操作简单,灵敏度高,适用于水质中镉元素的测定。     

微波消解–ICP–OES法测定陶土中铅和镉含量

建立微波消解–ICP–OES法测定陶土中铅和镉含量的方法。采用氢氟酸–硝酸作为消解液,微波消解法处理样品,消解液定容后直接进入耐氢氟酸的进样系统,用ICP–OES法测定陶土中重金属铅和镉的含量。结果表明,Pb和Cd检出限分别为0.027μg/m L和0.011μg/m L,回收率分别为90.5%~98.8%和95.0%~98.4%,测定结果相对标准偏差分别为1.38%和2.17%(n=7)。该方法具有快速、准确、灵敏度高等优点,适用于陶土中铅和镉含量的检测。     

极谱法同时测定海水中的铜、镉、铅、锌

建立极谱法同时测定海水中铜、镉、铅、锌的含量。在10.0～35.0℃条件下,试样于–1.15 V恒压下电解,富集在汞电极上生成汞齐,并随电极电位的变化而发生氧化还原反应,产生电流,通过标准加入法进行定性和定量。铜、镉、铅、锌的检出限分别为0.64,0.14,0.17,2.0μg/L,定量限分别为2.5,0.50,0.50,10.0μg/L。样品加标回收率为80.4%～106.0%,测定结果的相对标准偏差为0.43%～6.09%(n=6)。该法具有操作简便、抗干扰性能强、灵敏度高等特点,能够满足海水中铜、镉、铅、锌的监测要求。     

ICP–MS法测定食品接触纸制品中铬、镍、砷、镉、铅、汞

建立电感耦合等离子体质谱法(ICP–MS)测定食品接触纸制品中铬、镍、砷、镉、铅、汞6种重金属含量的方法。样品经微波消解处理后用ICP–MS进行测定,内标法定量。在优化实验条件下,测定汞元素的线性范围在0~10μg/L之间,测定铅、镉、铬、镍、砷元素的线性范围在0~100μg/L之间,相关系数均大于0.999。各元素的检出限为0.001~0.1 mg/kg,加标回收率为89.3%~116.0%,测定结果的相对标准偏差为3.5%~7.9%(n=6)。该方法样品处理简单,检测灵敏度高,适用于食品接触纸制品中铬、镍、砷、镉、铅、汞的检测。     

顺序注射氢化物发生-原子荧光光谱法同时测定环境水样中砷和镉

目的考察了光电倍增管负高压、砷和镉灯电流、原子化器高度、载气流量、屏蔽气流量、增敏剂等因素对测定结果的影响。方法建立一种顺序注射氢化物发生-原子荧光光谱法同时测定水样中砷和镉含量的方法。结果载流HCl的浓度为0.60 mol/L,KBH4质量浓度为20g/L,增敏剂硫脲和钴离子的质量浓度分别为80 g/L和70 g/L时,同时测定砷和镉的效果最佳。在最佳实验条件下,砷和镉的检出限分别为0.009 3μg/L和0.12μg/L,加标回收率为92.3%～103.9%,相对标准偏差小于3.5%,被测水样中共存离子对砷和镉的测定没有干扰。结论该法操作方便、快速,用于环境水样中砷和镉的同时测定,具有很好的可行性和实用性。     

微波消解-石墨炉原子吸收光谱法测定纸质食品包装材料中的痕量镉

建立了微波消解–石墨炉原子吸收光谱法测定纸质食品包装材料中痕量镉的检验方法。样品经微波消解后,以硝酸镍为基体改进剂,试验确定了石墨炉原子吸收法测定镉的最佳仪器条件。镉的质量浓度在0～10μg/L与吸收峰面积呈良好的线性关系,线性相关系数r=0.9997,检出限为0.025μg/L。将该法用于纸质食品包装材料中痕量镉的测定,并进行加标回收试验,回收率为96.0%～105.5%,相对标准偏差不大于4.4%(n=10)。     

高效液相色谱法测定阿达帕林含量

建立了高效液相色谱法测定阿达帕林的含量。以Kromasil C_(18)(250 mm×4.6 mm,5μm)为色谱柱,检测波长为234 nm,以甲醇–四氢呋喃–三氟乙酸–水(450∶25∶0.4∶24.6)为流动相,流量为1.0 mL/min,进样体积为10μL。阿达帕林的质量浓度在2.51～200.8μg/mL范围内与色谱峰面积呈良好的线性关系,相关系数为0.999 9,方法检出限为0.120 8μg/mL。样品加标回收率为99.04%～100.20%,测定结果的相对标准偏差为0.12%～0.24%(n=6)。该方法简便,测定结果准确、可靠,耐用性较强,适用于阿达帕林含量的测定。     

电感耦合等离子体原子发射光谱法同时测定锌冶炼酸浸渣中12种元素

建立电感耦合等离子体原子发射光谱(ICP–AES)同时测定锌冶炼酸浸渣中铅、铜、铁、镉、钴、镍、锑、钙、镁、铝、砷、锰12种元素的方法。样品采用硝酸–盐酸–氢氟酸–高氯酸四酸溶解,以体积分数为10%的盐酸–硝酸混合溶液为介质,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。铜、铅、铁、镉、钴、镍、锑的质量浓度在0.10～50μg/mL范围内,钙、镁、铝、砷、锰的质量浓度在0.10～10μg/mL范围内与光谱强度呈良好的线性关系,相关系数均大于0.999,方法检出限为0.002 1～0.025 5μg/mL。测定结果的相对标准偏差为0.012%～1.87%(n=6),样品加标回收率为99.0%～100.3%。采用该方法测定锌精矿成分分析标准物质和实验室内控样品,测定值与参考值基本一致,相对误差为0.00～3.33%。该方法简单、快速,具有较高的准确度和精密度,适用于锌冶炼酸浸渣样品中多元素同时测定,在锌冶炼行业具有重要的应用价值。     

顶空气相色谱-质谱法测定废水中挥发性有机化合物和卤化溶剂

建立顶空气相色谱–质谱法测定废水中挥发性有机化合物和卤化溶剂的含量。样品采用DB–624色谱柱净化,以顶空方式进样,用气相色谱–质谱法对挥发性有机化合物和卤化溶剂进行测定,外标法定量。挥发性有机化合物和卤化溶剂的含量在0.01～2.0μg范围内与峰面积呈良好的线性关系,相关系数均大于0.998,方法检出限为0.1μg/L。测定结果的相对标准偏差为1.30%～2.22%(n=6),样品加标回收率为85.3%～106.4%。该方法简单、快速,结果准确、可靠,适用于废水中挥发性有机化合物和卤化溶剂的测定。     

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.