超高效液相色谱-串联质谱法同时测定血液中115种农药

建立了超高效液相色谱-串联质谱法(UPLC-MS/MS)一针进样同时测定血液中115种农药的方法。血液样品与提取剂甲醇按1∶5体积比进行蛋白沉淀,涡旋振荡2 min,以12 000 r/min离心10 min,取上清液进行UPLC-MS/MS分析。质谱分析采用电喷雾离子源(ESI),正离子模式和负离子模式同时切换采集。结果表明,115种目标农药在1～200 ng/mL质量浓度范围内线性关系良好(r0.99),13%的目标农药检出限(S/N≥3)为0.2 ng/mL,其余目标物均为0.1 ng/mL,所有目标农药的定量下限(S/N≥10)均为1 ng/mL。在10、50、100 ng/mL加标水平下,方法的基质效应为81.8%～115%,目标农药的回收率为80.4%～109%,日内精密度(Intra-RSD)为1.6%～11%,日间精密度(Inter-RSD)为1.9%～13%。该方法简便快速、灵敏度高、稳定性好,适用于血液样品中多农药的定性定量分析。     

LC-MS/MS内标法测定水产品中三聚氰胺残留量

建立了高效液相色谱-电喷雾串联质谱(LC-MS/MS)测定水产品中残留的三聚氰胺的方法.以13C,15N标记三聚氰胺为内标,样品经三氯乙酸溶液沉淀蛋白,提取目标分析物,经SCX-C18均匀混合填装的反相色谱柱分离,选择反应监测(SRM)正离子模式测定.LC-MS/MS的检测低限为10 μg/kg;在10.0～500 ng/mL时峰强度与质量浓度的线性关系良好(r>0.99).方法的平均回收率为78%～118%.     

聚[2-(丙烯酰氧基)乙基]三甲基氯化铵-乙二醇二甲基丙烯酸酯整体柱固相萃取结合高效液相色谱法测定尿液中3种苯二氮■类药物

以[2-(丙烯酰氧基)乙基]三甲基氯化铵(DAC)为单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂在注射器中制备聚合物整体柱,用其固相萃取尿液中溴西泮(BRZ)、劳拉西泮(LRZ)和地西泮(DZP)3种苯二氮■类药物(BZDs),并采用高效液相色谱法(HPLC)分析。实验考察了整体柱聚合时间及固相萃取条件(淋洗溶液、洗脱溶剂种类和体积)对BZDs萃取效率的影响。结果表明,仅聚合4 h得到的整体柱对BZDs吸附效率为100%。取尿液样品4 mL上样,用4 mL H_2O冲洗,1 mL乙酸乙酯洗脱,采用高效液相色谱分析。在最优条件下,3种BZDs在4.0～1 000 ng/mL范围内线性关系良好(r=0.999),检出限(S/N=3)和定量限(S/N=10)分别为1.0～1.2 ng/mL和3.3～4.0 ng/mL;在10、25和50 ng/mL加标水平下回收率为81.4%～102%,日内(n=3)和日间(n=3)相对标准偏差分别为1.2%～4.5%和2.5%～8.3%。该整体柱可对尿液中3种BZDs有效净化,且富集达12～15倍。方法构筑的聚合物整体柱制备简单,萃取高效,可成功用于尿液中3种BZDs的分析。     

移液枪头式整体柱直接固相微萃取-高效液相色谱法测定尿液中苯二氮卓类药物

本文采用甲基丙烯酸2-羟乙酯(HEMA)与乙二醇二甲基丙烯酸酯在移液器枪头中共聚制备固相微萃取整体柱，用于直接处理尿液中3种苯二氮卓类药物(BZDs)。实验考察了单体用量、聚合时间及固相微萃取条件对BZDs萃取效率的影响，评价了其吸附性能。当HEMA用量为40 mg,聚合温度60℃时，固相微萃取整体柱对目标物吸附效率达98.9%～100%,且对尿液中杂质的吸附率低于10%。取3 mL尿液样品，无需处理，直接上样至该柱，经4 mL纯净水冲洗，1 mL乙腈洗脱，得到的样品结合高效液相色谱仪分析。方法对3种BZDs在2.5～1 000 ng/mL浓度范围呈现良好线性关系(r=0.999),检出限(S/N=3)和定量限(S/N=10)为0.8～1.5 ng/mL和2.5～5.0 ng/mL,回收率为86.2%～107%。本方法构筑的萃取柱制备简单，能实现对原始尿液的直接、高效萃取，操作便捷。     

QuEChERS结合超高效液相色谱-串联质谱法检验腐败血中4-甲基甲卡西酮和甲卡西酮

建立了腐败血中4-甲基甲卡西酮和甲卡西酮的超高效液相色谱-三重四级杆串联质谱(UPLC-MS/MS)检测方法。腐败血样品经乙腈水混合溶液(乙腈:水=4:1,V/V)提取,无水MgSO_4脱水和C_(18)吸附剂净化。选用Waters BEH C_(18)色谱柱分离,0.1%甲酸-水(5 mmol/L乙酸铵)和乙腈作为流动相进行梯度洗脱,电喷雾电离,正离子(ESI~+)模式扫描,多反应监测(MRM)模式检测。4-甲基甲卡西酮和甲卡西酮在0.5～100 ng/mL范围内线性关系良好(R~2≧0.9993),检出限(S/N=3)分别为0.01 ng/mL(4-甲基甲卡西酮)和0.03 ng/mL(甲卡西酮),定量限(S/N=10)分别为0.1 ng/mL(4-甲基甲卡西酮)和0.5 ng/mL(甲卡西酮)。     

浊点萃取-高效液相色谱法测定小儿泻速停颗粒中多酚类化合物

建立了基于表面活性剂浊点萃取-反相高效液相色谱法同时分离测定小儿泻速停颗粒中没食子酸、儿茶素、表儿茶素的方法。采用phenomenex C18色谱柱,流动相为乙腈-0.2%冰乙酸水溶液,采用梯度洗脱;流速0.8 mL/min;检测波长280 nm。没食子酸、儿茶素和表儿茶素分别在0.0104～223μg/mL,(r=0.9999);0.0152～108μg/mL,(r=0.9999);0.0184～132μg/mL,(r=0.9999)范围内线性关系良好,定性检测限(S/N=3)依次为:0.087 ng/mL,0.43 ng/mL,0.42 ng/mL。加入50 g/L NaCl来进行浊点富集,可提高萃取回收率。平均回收率为91.85%～98.48%,本方法可用于该制剂的质量控制。     

ZIF-8@Fe_3O_4磁性固相萃取结合高效液相色谱法测定果汁中3种苯甲酰脲杀虫剂

发展了磁性沸石咪唑酯骨架材料(ZIF-8@Fe_3O_4)磁性固相萃取结合高效液相色谱-二极管阵列检测器,测定果汁中氟幼脲、四螨嗪和氟啶脲3种苯甲酰脲杀虫剂(BUs)的新方法。利用X射线衍射仪、傅立叶变换红外光谱仪、扫描电子显微镜和振动样品磁强计对合成的ZIF-8@Fe_3O_4吸附剂进行表征,考察了溶液pH值、吸附剂用量、吸附时间、洗脱溶剂种类和体积(单次洗脱体积×洗脱次数)对BUs萃取效率的影响。在最优实验条件下,氟幼脲和四螨嗪在2.0～200 ng/mL、氟啶脲在3.5～350 ng/mL范围内线性关系良好(相关系数r=0.999),检出限(S/N=3)和定量下限(S/N=10)分别为0.6～1.0 ng/mL和2.0～3.5 ng/mL。3个加标水平下的回收率为82.7%～98.6%,日内和日间(n=3)相对标准偏差(RSD)分别为1.2%～6.1%和1.3%～9.0%。当上样体积为10 mL时,ZIF-8@Fe_3O_4对果汁中3种BUs的富集倍数为43.4～48.1倍,吸附剂重复使用10次后,3种BUs回收率的RSD不大于8.8%。该方法灵敏、高效,可用于果汁样品中BUs的分析。     

环境水体中亚硝态氮、硝态氮和总氮的液相色谱测定

建立了环境水体中NO2-、NO3-及总氮含量的液相色谱测定方法.采用Hypersil ODS(5μm,250mm×4.6mm i.d.)色谱柱;流动相:17.5mmoL/L KH2PO4-2mmol/L H3PO4缓冲液(pH3.5)-乙腈(体积比92.5:7.5);流速:0.8mL/min;柱温:30℃;紫外检测器:波长204nm.结果表明:水体中NO2-和NO3-的线性范围(以N计):1～80ng,r=0.999 9;方法检出限:NO2-0.4ng、NO3-0.09ng;回收率为NO2-99.2%～102.4%、NO3-98.7%～99.3%,RSD为0.79%和0.25%.     

激光热透镜光谱分析法同时测定铜、钴和镍研究

基于2-(5-NO2-吡啶-2-偶氮)-1-羟基-8-氨基萘-3，6-二磺酸与铜(Ⅱ)、钴(Ⅱ)和镍(Ⅱ)反应酸度的差异及热透镜信号强度的加和性，建立了激光热透镜光谱法同时测定铜、钴和镍的新方法。测定铜、钴和镍的线性范围依次为0～200ng/mL、0～200ng/mL和0～100ng/mL，检出限依次为2ng/mL，2．5ng/mL和1ng/mL。方法已用于合成样品及人发样中铜、钴和镍的同时测定。     

液相色谱-串联质谱分析组织中基因组脱氧核糖核酸羟甲基胞嘧啶水平

5-羟甲基胞嘧啶通过阻止脱氧核糖核酸(DNA)甲基化转移酶1(DMNT1)甲基化胞嘧啶来影响DNA甲基化的程度。本文建立了液相色谱-串联质谱(LC-MS/MS)测定组织中全基因组5-羟甲基胞嘧啶水平的方法。采用苯酚-氯仿提取组织DNA,提取的DNA用88%甲酸在140 ℃下裂解,DNA裂解液加入同位素胞嘧啶作内标,经N2吹干后,加乙腈-水(9:1, v/v)溶解,用LC-MS/MS检测5-羟甲基胞嘧啶的含量,并计算全基因组中5-羟甲基胞嘧啶的水平。结果表明,5-羟甲基胞嘧啶的线性范围为0.1～30 ng/mL,相关系数为0.9969,检出限(信噪比为3计)和定量限(信噪比为10计)分别为0.057 ng/mL和0.090 ng/mL;日内相对标准偏差和日间相对标准偏差分别为5.13%和6.24%;加标回收率为90.24%～97.53%。用该方法检测了大鼠大脑组织DNA羟甲基化水平,平均结果为0.66%。该方法简便,重现性好,灵敏度较高,能满足全基因组5-羟甲基胞嘧啶定量检测的要求。     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.