氢化物发生-原子荧光光谱法测定白酒中的痕量铅

建立氢化物发生-原子荧光光度法测定白酒中痕量铅的方法.对测定铅的影响因素进行分析和研究,优化了仪器的最佳工作参数,确定了最适宜的分析条件.铅标准溶液浓度在0～20.0μg/L范围内,标准曲线具有良好的线性,铅的检出限为1μg/L,回收率为94.0%～108.0%,相对标准偏差为3.28%～4.03%(n=11).     

氢化物原子吸收法测定高纯度碳酸钙中铅

通过氢化物原子吸收光谱法测定了高纯度天然碳酸钙中低浓度铅的含量,结果表明,在还原剂KBH4浓度为1.5%,载液HCl浓度1%,铅标曲线性范围1～20μg/L(r=0.9990),试样溶液加入总HCl量＜3%的条件下可获得满意结果,RSD小于5.9%,加标回收率在96.0%～104.8%之间.高浓度钙离子对测定无影响.     

改性壳聚糖的制备及对Cu2+Pb2+的吸附研究

用巯基乙酸作为巯基化剂,对壳聚糖进行改性,选择了巯基化的条件.实验表明,在浓度为188mg/L的铜溶液中,CTS-SH的最大吸附率达90.3%以上,吸附容量为27.76mg/g,在浓度为203mg/L的铅溶液中,对铅的最大吸附率达到99%以上,在浓度为1.015g/L的铅溶液中,最大吸附率达95.5%.此时的吸附容量为97.4mg/g,吸附容量大于147.2mg/g时的吸附率为36.3%.经XRD及EMS图片的分析,可以看出,改性壳聚糖在吸附前后,结构发生了改变.     

微波辅助提取原子吸收光谱法快速检测食品中铅、镉、锰、锌

采用微波辅助提取样品,建立食品中铅、镉、锰、锌的原子吸收光谱快速检测方法。以1%（体积分数）硝酸溶液为提取溶剂,在提取温度为120℃、提取时间为30 min、样品质量为0.2～0.3 g的条件下,食品中的铅、镉、锰、锌提取率均能达到81%～109%。铅的质量浓度在0～10μg/L范围内,镉的质量浓度在0～2.00μg/L范围内,锰、锌的质量浓度在0～1 000μg/L范围内与吸光度具有良好的线性关系,相关系数均大于0.999。当取样质量为0.3 g、定容体积为10 mL时,样品中铅、镉、锰、锌的检出限分别为0.006、0.001、0.2、0.05 mg/kg。在优化的实验条件下,标准物质GBW10051中4种元素测定结果的相对标准偏差均小于10%(n=6),6种不同种类的国家标准物质的测定值与认定值基本一致,8种实际样品的测定结果与国标法测定结果的相对偏差为-19%～15%。该方法硝酸用量少,样品处理效率高,测量准确度高,适用于食品中铅、镉、锰、锌的快速检测。     

循环伏安法测定血浆中的葡萄糖

采用三同铜电极体系,在16 g/L NaOH、20 g/L Na2SO4溶液中,采用循环伏安法检测血浆中的葡萄糖浓度.葡萄糖浓度c在0.2～2.4 g/L范围内与峰电流ipc呈线性关系,线性方程为c=5.255-5.46ipc,线性相关系数为0.9946,方法的检测上、下限分别为2.06 g/L和0.2 g/L.相对误差为0.57%～6.84%,相对标准偏差为1.27%～4.10%.     

微波消解-电感耦合等离子体质谱法测定淀粉制品中的铬、铅、铝、镍、铁

建立电感耦合等离子体质谱法同时检测淀粉制品中铬、铅、铝、镍、铁5种金属残留的检测方法。利用微波消解仪对样品进行消化处理,用电感耦合等离子体质谱仪进行检测,内标法定量。铬、铅、铝、镍、铁5种金属元素的质量浓度在0.30～50.0μg/L范围内线性关系良好,相关系数(r~2)不小于0.990。检出限分别为铬0.08μg/L,铅0.04μg/L,铝0.09μg/L,镍0.04μg/L,铁0.05μg/L。5种待测元素的加标回收率为84.8%～107.3%,测定结果的相对标准偏差小于5%(n=6)。该方法样品处理简单,灵敏度高,检测结果准确,可用于淀粉制品中铬、铅、铝、镍、铁5种金属残留的检测。     

新型含异噁唑单元的吡唑酰胺类衍生物的合成及杀虫活性

运用活性亚结构拼接的原理,以杀虫剂氯虫苯甲酰胺为先导结构,引入异噁唑环单元,合成了16个含异噁唑环取代的新型吡唑酰胺化合物,采用¹H NMR、¹³C NMR、元素分析等方法对其目标物的结构进行了表征.初步生物活性测试数据显示,大多数化合物在500μg/m L浓度下对粘虫呈现出100%的杀死率.其中3个化合物在100μg/m L浓度下对粘虫的杀死率达80%～100%,在浓度降至20μg/m L时,3个化合物对粘虫仍表现出40%～50%的杀虫活性.3个化合物在500μg/m L浓度下对蚜虫显示出100%的杀虫效果,在100μg/m L浓度下对蚜虫仍有70%～100%的杀虫活性.另外2个化合物在500μg/m L时对朱砂叶螨的防效为90%～100%.     

电感耦合等离子体质谱（ICP-MS）法测定食用植物油中铅和砷的含量

采用改进的微波消解-电感耦合等离子体质谱(ICP-MS)法,实现了对植物油中铅、砷的定量测定,弥补了微波消解植物油前处理不彻底的不足。铅、砷浓度在0～50μg/L范围内具有良好的线性关系(r≥0.999),相对标准偏差(RSD)为1.2%～4.9%,加标回收率为81.0%～109%,检出限分别为1.11μg/kg和0.90μg/kg,能满足现有标准的检测要求。     

石墨炉原子光谱法测定工业废渣中痕量元素砷、铅、铬、钡、银

建立了石墨炉原子吸收光谱法测定检测工业废渣中痕量元素砷、铅、铬、钡、银的方法。采用悬浮进样,硝酸-硫酸混合酸溶解样品。10g/L Mg(NO3)2作基体改进剂,提高了砷的灰化温度,加入10g/L CaCO3防止钡在石墨炉中形成不易挥发的碳化钡,增加了钡的灵敏度。回收率为98%～112%,测定结果的相对标准偏差为2.22%～4.46%。As的线性范围2～80μg/L,Pb的线性范围1～60μg/L,Cr的线性范围0.5～20μg/L,Ba的线性范围5～150μg/L,Ag的线性范围1～100μg/L。     

石墨炉原子吸收光谱法测定羊剪绒制品中铅、铬、钴

采用人工汗液萃取法处理样品,提出了石墨炉原子吸收光谱法同时测定羊剪绒制品中铅、铬和钴含量的方法。1.000g样品用30mL人工汗液于40℃萃取20min,选择铅、铬和钴的灰化温度和原子化温度分别为650℃,1 000℃,1 200℃和1 500℃,2 300℃,2 100℃。在优化的试验条件下,铅、铬和钴的质量浓度分别在10.00～100.0μg.L-1,20.00～100.0μg.L-1,20.00～100.0μg.L-1范围内与吸光度呈线性关系,方法的检出限(3S/N)分别为0.038,0.091,0.086μg.L-1。方法可用于羊剪绒制品中铅、铬和钴含量的测定,回收率分别在95.5%～97.3%,93.9%～97.7%,98.5%～99.3%之间,测定值的相对标准偏差(n=5)均小于5.0%。     

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.