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1.
用2-琉基苯并噻唑/醋酸丁酯pH7~8萃取体系,预浓集以后,用火焰原子吸收测定环境水中癌量Cu,Zn,Cd、Pb,回收率在95%~105%,相对标准偏差为2%~5%(x=6),植出限为Cu0.2μg/L,Zn0.08μg/L、Cd0.03μg/L、Pb0.8μg/L。 相似文献
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生物样品中Se的荧光测定方法 总被引:1,自引:0,他引:1
运用微波消化系统处理生物样品,以2,3-二氨基萘为荧光试剂建立了一种测定生物样品中Se的荧光分光光度法。方法的最低检出限为1.6ng/mL,线性范围0~0.600μg/mL,回收率92.22%~99.78%,连续10次测定样品变异系数(CV)为0.4%(n=10),隔213重复实验变异系数为1.54%。该法具有灵敏、稳定、可靠等优点,适用于生物样品中Se含量的测定。 相似文献
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采用NHO3+HF+H2O2体系微波消解垃圾焚烧飞灰,火焰原子吸收光谱法测定金属Cu,Fe,Pb,Ni,Mn,Cr和Cd的含量。结果表明,飞灰中Cu质量分数为0.8927mg/g,Pb质量分数为1.8490mg/g,Ni质量分数为0.1523mg/g,Mn质量分数为1.1033mg/g,Fe质量分数为86.4517mg/g,Cr质量分数为0.3667mg/g,Cd质量分数为0.0581mg/g。铁的检测限为3.9041mg/L,其它元素均小于1mg/L,加标回收率在98.0%-108.0%之间。RSD〈4.0%。该法简便快速,具有较好的准确度和精密度,测定结果为处理垃圾焚烧所产生的飞灰提供了理论依据。 相似文献
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建立了过氧化钠熔融分解样品、电感耦合等离子发射光谱法(ICP-AES)测定锡精矿中锡、铜、铅、铁的新方法。对试样分解方法、过氧化钠用量、元素分析谱线等进行了讨论。选择过氧化钠用量为2.0g,样品熔融温度为850~C,锡、铜、铅、铁分析谱线分别为189.991,324.754,220.353,259.940nm。将该方法应用于标准样品(BY0107—1)中Sn,Cu,Pb,Fe的测定,待测元素的回收率在92.0%-101.6%之间,检出限为分别为0.006,0.002,0.005,0.001μg/mL,测定结果的相对标准偏差为0.16%~2.11%(n=5)。 相似文献
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基质固相分散-加速溶剂萃取-气相色谱法测土壤中有机氯农药残留 总被引:17,自引:0,他引:17
建立了用弗罗里硅土作基质固相分散剂的加速溶剂萃取、并以灭蚁灵(Mirex)为内标的快速、同时测定土壤中16种有机氯农药的气相色谱法。加速溶剂萃取仪在100℃,10.3Mpa用正己烷和丙酮(1:1,V/V)静态提取样品10min,0.01μg/g加标水平回收率为77.3%-101.3%;方法检出限为0.01—0.04ng/g。方法满足了土壤中有机氯农药残留测定的要求。对我国南方不同地域的72个土壤样品进行了测定,大部分有机氯农药在土壤中都有一定检出量,其中环氧七氯最高(2.6~844.5ng/g),甲氧DDT(23.2—219.8ng/g)和P,P’-DDT(4.0—183.1ng/g)次之,而o,P'-DDT在72个土样中都没有检出。 相似文献
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微波辅助萃取气相色谱-质谱联用测定蔬菜中的扑草净 总被引:4,自引:0,他引:4
研究了微波辅助萃取气相色谱.质谱联用测定植物样品中扑草净的方法,比较了几种不同溶剂的微波萃取效率,从而选取二氯甲烷为萃取溶剂,并采用三因素三水平的正交设计试验对溶剂体积、微波辐射时间、微波功率进行了优化。在优化的实验条件下分析了合成菠菜样品,对0.2μg/g和0.02μg/g的合成菠菜样品,回收率分别为99.5%和92.5%,相对标准偏差分别为5.0%和ll%,方法的线性范围为1.0—400ng/g,检出限为0.22ng/g。方法适合于分析植物样品中的扑草净。 相似文献
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活性炭微柱在线流动注射预富集-火焰原子吸收快速顺序测定铜、钴、镍、镉、铅的研究 总被引:6,自引:0,他引:6
采用双柱富集的流动注射在线预富集系统与220FS顺序多元素原子吸收分光光度计联用,使用圆锥型活性炭微柱为预富集柱,在pH4~5.5范围内,以吡咯啶二硫代氨基甲酸铵(APDC)为络合剂,6mol/L HNO3为洗脱剂,实现了Cu、Co、Ni、Cd、Pb5种元素的快速顺序测定。该体系对以上5种元素的富集倍数为9.8~15.5之间,34s富集的检出限(3σ)Cu为1.81,Co为3.10,Ni为1.66,Cd为0.28,Pb为4.90μg/L;相对标准偏差Cu 1.13%;Co1.24%;Ni2.26%;Cd0.95%;Pb1.77%。 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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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%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Jona Mirnik Eva Pušavec Kirar Sebastijan Ričko Uroš Grošelj Amalija Golobič Franc Požgan Bogdan Štefane Jurij Svete 《Tetrahedron》2017,73(24):3329-3337
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 CuI 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). 相似文献
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George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(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. 相似文献