液相色谱串联质谱法测定鸡蛋中喹诺酮类药物残留

建立了鸡蛋中8种喹诺酮类残留的高效液相色谱串联质谱检测方法。样品用EDTAM cllvaine缓冲液提取,正己烷脱脂后,经HLB固相萃取柱净化,用LC-M S/M S进行检测,内标法定量。8种喹诺酮药物含量在0.5~50μg/kg浓度范围内线性关系良好,相关系数(r)均大于0.999。方法检出限为0.1~0.5μg/kg,定量限为0.3~1.7μg/kg,加标回收率为81.8%~118.4%,相对标准偏差均小于9.6%。该方法适用于鸡蛋中喹诺酮类药物残留量的检测。     

通过式固相萃取净化-液相色谱-串联质谱法测定豆芽中10种喹诺酮类抗生素

建立了超高效液相色谱-串联质谱(UPLC-Ms/Ms)快速检测豆芽中10种喹诺酮类抗生素(QNs)的方法。样品用乙腈-0.1%甲酸水溶液提取后,经PRiME HLB快速净化,氮吹浓缩后,用电喷雾离子源正离子-多反应监测(MRM)模式串联质谱进行检测。在0.25~100μg/L范围内,10种目标物的线性关系良好,其相关系数均大于0.997。方法对两种豆芽基质进行前处理并测定,检出限为1.0μg/kg和2.0μg/kg,定量限为3.0μg/kg和6.0μg/kg。回收率实验结果表明:10种目标物回收率范围为78.1%~106.4%,RSD<8.1%。方法能有效地避免杂质的干扰。     

超高效液相色谱-串联质谱法测定鸡肉中头孢拉定残留

建立测定鸡肉中头孢拉定残留的超高效液相色谱-串联质谱分析方法。鸡肉样品经80%乙腈水溶液提取,PRiME HLB柱固相萃取净化,0.2%甲酸水溶液稀释,采用Waters ACQUITY UPLC HSS T3色谱柱(100 mm×2.1 mm,1.8μm)分离,以0.1%甲酸-0.1%甲酸乙腈为流动相,梯度洗脱,基质加标外标法定量。实验结果表明,头孢拉定在0.5～50.0 ng/mL浓度范围内呈良好的线性关系(R~2=0.9998),定量限为1μg/kg。向空白鸡肉中添加头孢拉定含量为1.00μg/kg、2.00μg/kg、10.0μg/kg时,回收率在77.3%～106.8%之间,相对标准偏差在3.2%～10.5%之间。本方法操作简便、快捷,实验结果准确、稳定,可满足鸡肉中头孢拉定残留量的检测。     

超高效液相色谱-串联质谱测定饲料中镇静剂类和β-受体激素类药物残留

采用超高效液相色谱-串联质谱技术,建立了饲料中8种镇静剂类和15种β-受体激素类药物残留的分析检测方法。样品采用乙腈-1%(体积分数)三氯乙酸水溶液(7∶3,v/v)提取,目标物通过阳离子固相萃取柱净化,经Agilent Zorbax Eclipse Plus C_(18)色谱柱(100 mm×3.0 mm,1.8μm)分离,液相色谱-串联质谱进行检测,标准曲线内标法定量。结果表明:23种目标物在2.0~200.0μg/L内线性关系良好(r20.99)。在饲料样品基质中,目标化合物在5.0、10、50μg/kg 3个加标水平下的平均回收率为75.1%~102.4%,相对标准偏差(RSD)为4.3%~14.3%(n=6)。该方法净化效率高,适用范围广,可用于饲料中镇静剂类和β-受体激素类药物残留筛查和检测。     

通过式固相萃取净化/液相色谱-串联质谱法快速检测水产品中11种青霉素残留

采用通过式固相萃取净化策略去除样品基质中的脂肪和磷脂等杂质干扰,结合液相色谱-串联质谱检测,建立了水产品中11种青霉素残留的同时快速分析方法。样品经80%乙腈水溶液提取,Oasis PRi ME HLB通过式固相萃取柱净化,C_(18)色谱柱分离,0.05%甲酸乙腈溶液和0.05%甲酸水溶液梯度洗脱,多反应监测正离子模式扫描,内标法定量。11种目标物在相应浓度范围内线性关系良好,相关系数不低于0.99,检出限为0.30~1.5μg/kg。基质加标回收率为85.5%~110%,相对标准偏差(RSD)为5.9%~14.3%。该方法前处理操作简便,灵敏度和准确度高,可实现水产品中多种青霉素药物残留的同时快速测定。     

液相色谱串联质谱同位素稀释法对蜂王浆中10种硝基咪唑类药物残留的检测

建立了液相色谱-电喷雾串联质谱法(LC-ESIMS/MS)测定蜂王浆中10种硝基咪唑类药物残留的分析方法。蜂王浆样品经甲醇沉淀蛋白质,弱碱性条件下乙酸乙酯提取硝基咪唑类药物残留,Oasis(HLB)和C18固相萃取柱净化后,通过液相色谱-质谱联用技术进行检测(正离子方式,多反应监测模式),采用同位素稀释内标法或外标法进行定量。方法的线性范围为5.0~60μg/kg,相关系数大于0.999,在10、20、50μg/kg加标水平的回收率为70%~105%,相对标准偏差小于12.7%,定量下限均为10μg/kg。该方法定量准确,适用于对蜂王浆中硝基咪唑类药物残留的确证检测。     

超高效液相-串联质谱法同时测定蜂蜜中15种喹诺酮类药物残留

建立了蜂蜜样品中15种喹诺酮类兽药残留的超高效液相色谱-串联质谱检测方法。蜂蜜样品用磷酸盐缓冲溶液溶解提取后,用Oasis HLB固相萃取柱净化,超高效液相-电喷雾串联四级杆质谱检测,外标法定量。测定时用Acquity UPLC BEHC18色谱柱(50 mm×2.1 mm,1.7μm)分离,体积分数0.1%甲酸溶液-乙腈系统梯度洗脱,质谱测定采用多重反应监测(MRM)模式。15种喹诺酮类兽药的检出限均低于或等于1.0 ng/mL,回收率均在78.6%～112.9%范围内,相对标准偏差均在10%范围内。该方法各项指标均能满足国内外各项法规的要求,可用于蜂蜜样品中喹诺酮类药物残留的定量和定性检测。     

通过型固相萃取-液相色谱-高分辨质谱法快速测定粮谷中17种酰胺类农药残留量

应用PRiME HLB固相萃取柱通过式净化技术,采用液相色谱-四极杆静电场轨道阱高分辨质谱(LC-Q Orbitrap),建立了粮谷中17种酰胺类农药的检测方法。样品经乙腈提取,PRiME HLB固相萃取柱净化,在GL Intersil ODS-3色谱柱上以0.5%甲酸水和乙腈为流动相进行梯度洗脱,四极杆静电场轨道阱高分辨质谱以Full Scan/ddMS^2模式进行检测。结果表明,各组分在各自浓度范围内线性关系良好,相关系数均大于0.996。方法定量限在0.5~5μg/kg之间。待测物在5.0,10.0,50.0μg/kg 3个浓度水平下加标回收率在70.4%~101.6%之间,相对标准偏差在2.7%~10.8%之间。该方法可用于粮谷中酰胺类农药的测定。     

超高效液相色谱-电喷雾串联质谱法同时分析鸡肉中7种氟喹诺酮类药物残留

建立了一种同时测定鸡肉中7种氟喹诺酮类药物残留的超高效液相色谱-电喷雾串联质谱确证分析方法(UPLC-ESI-MS/MS)。样品经酸化乙腈提取、正己烷脱脂和HLB固相萃取柱净化,采用ACQUITY UPLCTM BEH C18色谱柱(50 mm×2.1 mm,1.7 μm)分离,以0.1%甲酸水溶液和乙腈作为流动相进行梯度洗脱,电喷雾质谱检测,正离子多反应监测模式进行定性和定量分析。7种药物在5～100 μg/kg范围内线性关系良好,相关系数(r2)均大于0.99;以5,25,50 μg/kg3个浓度水平进行添加回收试验,7种药物的平均回收率在79.2%～108.6%之间,相对标准偏差为4.2%～8.9%,方法的检出限(LOD)为0.2～1.4 μg/kg。方法重现性好、灵敏度高、分析时间短、确证能力强,适用于鸡肉中氟喹诺酮类药物多残留的确证检测。     

通过式固相萃取净化/高效液相色谱-串联质谱法快速测定水产品中6种麻醉剂残留

建立了一种快速测定水产品中6种麻醉剂(普鲁卡因、利多卡因、布比卡因、丁卡因、3-氨基苯甲酸乙酯甲基磺酸盐、苯佐卡因)的高效液相色谱-串联质谱分析方法。样品以水和1%甲酸乙腈提取,提取液经PRiME HLB固相萃取柱净化,以乙腈和0.1%甲酸水溶液为流动相梯度洗脱,ZORBAX Eclipse XDB-C_(18)色谱柱(3.0 mm×150 mm,3.5μm)分离,多反应监测(MRM)正离子模式检测,外标法定量。结果表明,6种组分在各自质量浓度范围内线性关系良好,相关系数(r~2)为0.993 8～0.998 7,方法检出限(LOD)为1.5～6.0μg/kg,定量下限(LOQ)为5.0～20μg/kg,平均加标回收率为76.8%～110%,相对标准偏差为4.2%～11%。该方法前处理操作简单、快速、准确、灵敏,适用于水产品中6种麻醉剂残留的快速测定。     

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.