固相萃取-在线凝胶渗透色谱-气相色谱/质谱法测定松子仁中的28种有机氯农药和拟除虫菊酯农药

建立了松子仁中28种有机氯农药和拟除虫菊酯农药多残留的在线凝胶渗透色谱-气相色谱/质谱（GPC-GC/MS）分析方法。样品以乙腈-水(体积比为4∶1)为提取剂高速匀浆提取,提取液经Aluminium-N固相萃取柱净化,除去样品中大部分的脂肪和甾醇等干扰基质,再经在线GPC进一步除去样液中的色素和脂肪等大分子干扰物质,有效地降低了样品复杂基质带来的背景干扰。加标水平为0.05 mg/kg时,大部分农药的回收率为70%～120%,相对标准偏差小于15%。28种农药的检出限为0.002～0.05 mg/kg。采用外标法定量,方法的线性关系和回收率结果均令人满意。实验证明,该方法是一种快速、准确、灵敏度高的同时检测松子仁中农药多残留的检测方法。     

凝胶渗透色谱净化-气相色谱分离同时测定糙米中50种有机磷农药残留

研究了同时检测糙米中50种有机磷农药残留的方法。用乙酸乙酯提取,凝胶渗透色谱净化,环己烷二氯甲烷(50∶50,V/V)作为流动相,气相色谱氮磷检测器检测。方法检出限为0.001～0.089mg/kg;相对标准偏差为1.7%～18.9%;40多种农药平均回收率在70%～120%。     

菌类食品中多种有机磷农药的气相色谱-离子阱二级质谱联用法测定

研究了气相色谱-二级质谱联用技术测定菌类食品中甲胺磷、速灭磷等44种有机磷农药残留的方法,依据待测物化学性质,对预处理方法和质谱分析条件进行了优化.样品加入水浸泡,氯化钠盐析,采用乙酸乙酯-环己烷(1 ∶ 1,体积比)匀浆提取2次,合并上层有机相,用无水硫酸钠柱脱水,40 ℃水浴旋转蒸发至近干,以乙酸乙酯-环己烷(1 ∶ 1)定容,凝胶渗透色谱和固相萃取方法(石墨化炭黑小柱)两步净化,氮气吹干后,乙酸乙酯定容至0.25 mL,采用HP-5MS柱,无分流进样,气相色谱-离子阱二级质谱方法进行定性和定量分析,外标法定量.44种农药在0.05 ～10.00 mg/L范围内呈线性关系,在0.05 ～0.5 mg/kg加标范围内的回收率为68% ～116%,相对标准偏差为5.4% ～13.4%,44种有机磷农药的检出限为0.01 ～0.1 mg/kg,满足菌类食品中有机磷农药残留限量的检测.     

固相萃取-气相色谱法测定茶叶中多种有机磷农药

建立了固相萃取-气相色谱法同时测定茶叶中16种有机磷农药残留的方法.样品用丙酮超声提取后,经自制的N-丙基乙二胺(PSA)/活性炭固相萃取柱净化,以混合溶剂乙腈/甲苯(V(乙腈)∶V(甲苯)=1∶3)洗脱,采用气相色谱-氮磷检测器(GC-NPD)测定.方法的回收率在62.8%～109.1%之间,相对标准偏差小于14.7%1,6种有机磷农药的检出限在0.01～0.16 mg/kg之间.方法快速简便、经济实用。     

基于气-液微萃取结合气相色谱-质谱法快速检测植物源性食品中28种农药残留

利用气-液微萃取(Gas-Liquid Microextraction, GLME)技术,结合气相色谱-质谱法建立快速检测植物源性食品中农药残留的分析方法。准确称取3 g匀浆样品,加入3 mL二氯甲烷∶乙酸乙酯(1∶1,V/V)超声提取15 min,取上清液100μL,通过GLME技术进行萃取净化,结合内标法,联用气相色谱-质谱法(Gas Chromatography-Mass Spectrometry, GC-MS),建立植物源性食品中农药残留的快速检测。28种残留农药在0.001～1.0 mg/kg范围内线性关系良好,相关系数为0.9991～0.9999,仪器定量限为0.0010～0.0370 mg/kg,样品平均加标回收率为65.6%～114.1%,相对标准偏差范围为3.2%～19.9%。该方法简便、快速、准确度高、重现性好,能够有效净化色素、脂类等干扰物质,适用于复杂基质的植物源性食品中农药残留检测。     

气相色谱-串联质谱法同时测定白芍中10种有机磷农药残留

建立了同时测定中药白芍中10种有机磷农药残留含量的气相色谱–串联质谱方法。样品用乙腈超声提取,提取液经凝胶渗透色谱净化后,以VF–5毛细管色谱柱(30 mm×0.25 mm,0.25μm)分离,串联四极杆质谱仪为检测器进行定性、定量分析。10种有机磷农药残留的检出限为0.02～4.0 mg/kg,实际样品的加标回收率为75%～105%,相对标准偏差为4%～10%。该方法能够满足白芍中有机磷农药残留的定性、定量检测要求。     

固相萃取-气相色谱法检测茶叶中的有机磷农药残留量

建立了茶叶中22种有机磷农药的残留量的气相色谱分析方法. 样品用V(乙腈)∶V(丙酮)＝4∶1提取, 经Envi-Carb固相小柱净化, 以V(乙腈)∶V(甲苯)＝3∶1洗脱, GC-FPD检测, 外标法定量. 在添加0.05～1.0 mg/kg的水平, 22种有机磷的平均回收率在81.3%～107.9%之间, 相对标准偏差在1.1%～8.9%, 该方法的检出限为0.01～0.04 mg/kg. 该方法的灵敏度、准确度和精密度均符合农药残留量测定的技术要求.     

土壤中多种有机磷及氨基甲酸酯类农药残留量的气相色谱-质谱法测定

建立了气相色谱-质谱法测定土壤中12种有机磷和氨基甲酸酯类农药残留分析方法。以丙酮-石油醚(4∶1,V/V)为提取剂,采用超声波提取土壤中农药残留,经弗罗里土层析柱净化,气相色谱-质谱(选择离子模式)法同时测定了土壤中多种有机磷和氨基甲酸酯类农药。该法对0.1μg/mL和0.5μg/mL两个浓度添加水平的回收率分别为70.1%~119.0%和78.1%~119.1%,相对标准偏差分别为6.30%~9.80%和5.20%~8.23%。     

气相色谱-负化学离子源质谱法测定含硫蔬菜中残留的14种农药

建立了含硫蔬菜(大葱、大蒜、蒜薹及韭菜等)中14种农药残留的气相色谱-负化学离子源质谱(GC-NCI/MS)检测方法。样品先采用微波加热处理除去大部分的含硫干扰物,然后用乙腈均质提取,提取液用凝胶渗透色谱(GPC)和N-丙基乙二胺(PSA)固相萃取小柱净化后用GC-NCI/MS在选择离子监测模式下测定。在50 μg/kg加标水平下回收率为49.2%～113.1%,相对标准偏差为1.42%～8.70%,检出限(以3倍信噪比计)为0.5～10.0 μg/kg。方法的选择性好,抗干扰能力强,能消除复杂基质带来的干扰,适合于含硫蔬菜中农药残留的确证分析。     

QuEChERS-在线凝胶渗透色谱-气相色谱-串联质谱法高通量筛查动物源性食品中的多农药残留北大核心CSCD

将QuEChERS技术与在线凝胶渗透色谱-气相色谱-串联质谱(GPC-GC-MS/MS)技术结合,建立了动物源性食品中196种农药残留的高通量检测方法。样品经乙腈提取、QuEChERS结合在线GPC净化后,进行GC-MS/MS检测,多反应监测模式(MRM)分析,外标法定量。方法优化了提取溶剂及净化剂类型,实现了目标物的高效提取和基质的有效去除;考察了在线GPC对样品溶液的净化作用。通过研究不同馏分接收时间段内目标物的回收率和基质效应,得出最佳馏分接收时间,实现目标物的有效导入和基质的高效去除,并对QuEChERS-GPC联用技术的优势进行了评价。该方法研究了196种农药的基质效应,其中10种农药表现为中等强度基质效应,4种农药为强基质效应。本研究采用基质匹配标准溶液进行定量,结果表明,196种农药在0.005~0.2 mg/L范围内线性关系良好,相关系数均>0.996,方法的检出限为0.002 mg/kg,定量限为0.005 mg/kg。向猪肉、牛肉、猪肝3种不同脂肪含量基质的空白样品中添加标准溶液,196种农药在3个加标水平下(0.01、0.05、0.20 mg/kg)的平均回收率为65.3%~126.2%,精密度为0.7%~5.7%。本方法快速、准确、灵敏,适用于动物源性食品中多农药残留的高通量筛查与检测。     

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.