高效液相色谱法同时测定甜瓜样品中的抑霉唑和噻菌灵

提出了一种用高效液相色谱法 (HPLC)同时测定甜瓜样品中的抑霉唑和噻菌灵残留量的方法。用乙酸乙酯作提取剂提取甜瓜样品 ,通过一个净化步骤分离样品中共提取组分。采用InertsilC8 3色谱柱 (15 0mm× 4 .6mm ,5 μmi.d ,) ,流动相为乙腈∶水 =75∶2 5 ,外标法定量 ,方法的检出限噻菌灵为 0 .70ng ,抑霉唑为1.5 3ng ;回收率为 87.5 %～ 98.0 % ;相对标准偏差为 1.5 %～ 4 .2 %。本法用于甜瓜样品中抑霉唑、噻菌灵含量的测定 ,获得了满意的结果。     

荔枝中抑霉唑和嘧霉胺残留量的超高效液相色谱-串联质谱法同时测定

建立了超高效液相色谱-串联质谱法同时测定荔枝中抑霉唑和嘧霉胺的方法,对提取试剂、流动相、质谱条件进行了研究,并对抑霉唑和嘧霉胺可能的断裂机理进行了推测。待测样品直接用乙腈提取,采用电喷雾离子源(ESI)、多反应监测正离子模式扫描,外标法定量。抑霉唑、嘧霉胺的质量浓度在1.00～20.0μg/L范围内与峰面积呈良好线性,方法的检出限为0.005mg/kg;添加水平为0.005、0.010、0.020mg/kg时抑霉唑和嘧霉胺的平均回收率分别为91%～96%和83%～90%,相对标准偏差分别为6.5%～8.4%和9.5%～11.1%。该方法快速、简便、准确,可用于荔枝中抑霉唑和嘧霉胺残留量的定性与定量检测。     

凝胶渗透色谱净化-气相色谱-质谱法测定柑橘及其制品中抑霉唑的残留量

提出了气相色谱-质谱法测定柑橘及其制品中抑霉唑保鲜剂残留量的方法。样品用乙酸乙酯-环己烷(1+1)混合溶剂提取,所得提取液须经凝胶色谱净化去除大分子干扰物质。采用气相色谱分离后,选择离子监测模式下质谱法进行测定。方法检出限(3S/N)为0.02mg.kg-1,测定下限(10S/N)为0.05mg.kg-1。在3个标准加入水平下进行了回收试验,所得回收率在79.0%～92.1%之间,相对标准偏差(n=6)小于10%。     

粮谷中抑霉唑残留的气相色谱法测定

报道了气相色谱法测定粮谷中抑霉唑残留的方法.选取稻谷、小麦、燕麦和黍(大黄米)4种粮谷产品为研究对象,考察了不同类型检测器、不同提取体系、不同淋洗曲线和不同离心时间的破乳效率对抑霉唑测定的影响.试样以正己烷-乙酸乙酯(体积比1 ∶ 1 )提取,经毛细管气相色谱柱HP-5(30 m×0.25 mm×0.25 μm)分离, μ-ECD检测器测定.方法检出限为0.005 mg/kg (S/N=3).添标水平为0.01、0.05、0.25和0.50 mg/kg时平均回收率为82% ～111%,相对标准偏差为5.5% ～11.5%.线性范围为0.05 ～1.0 mg/L(r2=0.999 4).该方法快速、灵敏、准确,适合粮谷中抑霉唑残留的测定.     

液液提取-固相萃取-气相色谱法测定牛肉中蝇毒磷残留量的研究

建立了液液提取-固相萃取-气相色谱火焰光度法(LLE-SPE-GC-FPD)测定牛肉中蝇毒磷的残留量.优化了气相色谱分离条件,研究了样品基质对蝇毒磷测定的影响,考察了Florisil固相萃取小柱和ODS固相萃取小柱的萃取效果,并选择乙酸乙酯为洗脱剂,考察了液-液提取和固相萃取的回收率.将该方法用于牛肉中蝇毒磷的测定,其检出限为0.02 μg/mL,回收率高于83%,相对标准偏差13.7%.使用气相色谱质谱仪(GC-MS)对样品中的蝇毒磷进行定性分析,其特征离子和相对丰度为362(100)、226(55)和210(40).     

离心破乳-气相色谱法测定黑米中残留抑霉唑的研究

报道了离心破乳-气相色谱法测定黑米中残留抑霉唑的方法. 考察了不同离心速率、不同离心时间的破乳效率. 试样以V(正己烷):V(乙酸乙酯)＝1:1提取, 经毛细管气相色谱柱HP-5 (30 m×0.25 mm×0.25 μm)分离, μ-ECD检测器测定. 方法检出限为1.0×10-3 mg/kg (S/N=3). 在添标水平0.05、 0.25和0.50 mg/kg时的平均回收率为92.3%～104.3%, 相对标准偏差为6.9%～9.3%. 线性范围为0.02～1.0 mg/L (r2=0.9994). 方法适合黑米中残留抑霉唑的测定.     

固相分散萃取与气相色谱-负化学离子源质谱联用法测定食品中三唑醇的残留量

建立了食品中三唑醇残留量的固相分散萃取-气相色谱-负化学离子源质谱联用检测方法。样品中三唑醇残留物由正己烷饱和的乙腈(含1%冰醋酸)提取,加入无水硫酸镁与无水醋酸钠振荡促使提取液分层后进行固相分散萃取净化,用气相色谱-负化学离子源质谱法进行测定与确证,外标法定量。方法具有良好的选择性和抗干扰能力,其检出限和定量限分别为0.001 mg/kg和0.003 mg/kg;线性范围为0.050～0.750 mg/L,相关系数为0.9947;在0.005,0.010,0.020 mg/kg共3个添加水平下的平均回收率为70%～110%,相对标准偏差不大于12.0%。该方法适合于多种食品中三唑醇残留量的确证分析。     

植物源食品中6种三唑类杀菌剂残留量的气相色谱法测定

建立了同时测定6种三唑类杀菌剂(四氟醚唑、戊菌唑、氟菌唑、己唑醇、丙环唑、氟环唑)残留量的气相色谱方法.植物源食品采用乙腈溶剂提取,无水硫酸镁、氯化钠盐析,经弗罗里硅土固相萃取柱净化后,用气相色谱/电子捕获检测器(GC/ECD)测定.结果表明:6种三唑类杀菌剂在0.01 ～0.5 mg/L范围内线性关系良好,相关系数均大于0.996,样品添加水平为0.05 ～0.20 mg/kg时的平均加标回收率为87% ～110%,相对标准偏差为3.0% ～5.6%,方法的检出限为0.002 ～0.007 mg/kg.该方法可同时满足植物源食品中多种三唑类杀菌剂残留量的检测需要.     

农产品中甲草胺残留量的气相色谱-质谱检测

建立了玉米、花生、菠菜、柑橘4种不同类型农产品中甲草胺残留量的检测方法。样品先用丙酮-水(体积比为8∶2)提取,经二氯甲烷液-液分配,再用凝胶色谱(GPC)和固相萃取(SPE)去除色素和提取待测物,最后采用气相色谱-质谱测定,外标法定量。甲草胺的添加水平为0.010～0.200 mg/kg时,平均回收率为86.0%～98.2%;相对标准偏差为5.1%～6.7%;方法的测定低限为0.010 mg/kg。     

气相色谱质谱联用法同时测定果蔬中5种防腐杀菌剂

建立了果蔬中5种防腐杀菌荆(噻苯咪唑、邻苯基苯酚、联苯胺、抑霉唑、联苯)同时测定的气相色谱质谱联用法.样品用V(丙酮):V(乙酸乙酯)=50:50超声萃取,脱水,浓缩定容,经GC/MS分析.5种防腐杀菌剂分离良好并排除了样品中杂质峰的干扰,加标平均回收率为96.7%～104.7%之间,相对标准偏差为1.5%～4.25%.检出限0.5～1.5μg/L.     

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.