液相色谱-大气压化学电离离子阱质谱法测定烟草中的游离茄尼醇

用液相色谱/大气压化学电离离子阱质谱建立了一种分析烟草中游离茄尼醇的方法。烟草样品用甲醇振荡提取30 min,在分析前无需进行其它前处理。在1.8μm快速分离C18色谱短柱上用V(甲醇)∶V(异丙醇)=85∶15等梯度洗脱实现了茄尼醇的快速分离。用不带碰撞能量的二级质谱全扫描选择监测离子m/z 613.6进行定量,检出限为0.4μg/L,RSD为1.1%,两种添加量的回收率分别为97%和99%。方法应用于不同烟草和烟草制品样品的检测分析。     

液相色谱-串联质谱测定面条和米粉中的硫脲

建立了米面制品中硫脲的液相色谱-串联质谱(LC-MS/MS)测定方法.实验优化了样品提取方法、液相色谱条件和质谱参数.样品用80%乙醇超声波提取,离子交换色谱分离,色谱柱为NUCLEOSIL 100-5SA 阳离子交换柱,流动相为乙腈-(1%乙酸+0.2%乙酸铵)水溶液(30: 70),流速0.5mL/min.采用电喷雾质谱正离子模式电离,多反应选择离子检测,检测离子对为m/z 77/60和m/z 77/43,其中m/z 77/60为定量离子对.结果表明: 本方法简便快速、准确可靠,相对标准偏差＜4.0%;回收率为83%～90%;检出限为0.5 mg/kg;定量下限为 5 mg/kg.     

高效液相色谱-串联质谱法测定稻米和稻壳中井冈霉素A的残留

本文建立了稻米和稻壳中井冈霉素A的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品用甲醇-水(9+1)涡旋提取,过滤膜后进行HPLC-MS/MS分析。用多反应监测技术确定井冈霉素A的两对离子对m/z498.2/178.1、m/z498.2/336.1为定性离子对,m/z498.2/178.1为定量离子对。方法的线性范围为0.005～0.2mg/L,其中稻壳的线性相关系数为0.9993,稻米的线性相关系数为0.9988。稻米、稻壳的0.05、0.1、0.5 mg/kg三个浓度的添加回收率为71.6%～88.8%,相对标准偏差(RSD)为1.89%～8.16%。方法的定量限(LOQ)为5μg/kg。     

高分辨快速液相色谱-串联质谱法测定肉制品中的刚果红

建立了肉制品中刚果红的高分辨快速液相色谱-串联质谱(RRLC-MS/MS)测定方法。均质后的样品经乙腈与正己烷混合溶剂(1∶1)提取,乙腈提取层离心后直接上机测试。使用Agilent XDB C18色谱柱,以乙腈和10 mmol/L甲酸铵水溶液为流动相梯度洗脱,采用多反应监测方式(MRM)负离子模式检测,定量离子对与定性离子对分别为m/z 325.0/416.0与m/z 651.0/152.0,外标法定量。结果表明,刚果红在0.1～10mg/L范围内线性关系良好(r2>0.999),加标回收率为91%～102%,RSD为1.2%～4.0%,检出限与定量下限分别为0.07 mg/kg和0.18 mg/kg。该方法准确、高效,可用于肉制品中刚果红染料的快速检测。     

高效液相色谱-质谱法对饲料及食品添加剂中三聚氰胺的测定

建立了饲料中三聚氰胺的高效液相色谱-质谱测定方法.色谱条件:Kromasil C18柱(4.6 mm×250mm,5 μm),流动相:乙腈-0.1%(体积分数)甲酸(体积比5:95),流速0.4 mL/min.采用正离子模式的电喷雾质谱检测,以一级质谱得到的准分子离子m/z 127作为母离子,进行碰撞诱导解离(CID)二级质谱(MS2)分析,选择母离子和MS2的碎片离子m/z 85、109定性确证,提取m/z 85、109、127三个离子质量色谱峰面积定量.实验优化了质谱条件.线性范围为0.01～0.5 mg/L,检出限0.01 mg/L(S/N=3),回收率为80%～99%.     

苯二氮卓类新精神活性物质Flubromazolam的快速检测

建立了气相色谱-质谱(GC-MS)和超高效液相色谱-串联四极杆飞行时间质谱(UPLC-Q-TOF MS)技术联合鉴定检材中flubromazolam的方法。未知样品用甲醇和水提取,取上清液,采用GC-MS和UPLC-Q-TOF MS进行分析。经GC-MS检测,保留时间为17.96 min的未知组分的质谱碎片主要特征离子峰有m/z 222,341,343,370,372,111,102,75。经UPLC-QTOF M S检测,保留时间为4.99 min的未知组分的准分子离子峰为m/z 371.0298,碰撞诱导解离(CID)模式下二级质谱主要离子有m/z 343.0114,302.9928,292.1118,263.0982,237.0951,223.0670。经美国缉毒署毒品分析谱库、缴获毒品分析科学工作组(SWGDRUG)分析谱库检索和文献查询获得的信息资料进行比对,确认目标物为flubromazolam。     

高效液相色谱-串联质谱法测定食品包装材料中全氟辛烷磺酰基化合物(PFOS)

建立了用高效液相色谱-串联质谱(HPLC/MS/MS)结合快速溶剂萃取测定食品包装材料中全氟辛烷磺酰基化合物(PFOS)的方法。采用乙腈溶剂,快速溶剂提取食品包装材料中的PFOS,提取液经0.2μm有机滤膜过滤后,以V(乙腈)∶V(10 mmol/L乙酸铵溶液)=80∶20为流动相,经HPLC分离后用多级反应监测(MRM)方式测定。用两个子离子的相对丰度定性,外标法定量。PFOS在0.002~0.1μg/mL范围内线性良好(R2=0.998),回收率为93.8%~101%,精密度RSD为1.6%~3.1%,方法检出限为0.4μg/m2(S/N≥10),满足欧盟法规对食品包装材料中PFOS的限量检测要求。方法可用于食品包装材料中PFOS的检测。     

高效液相色谱-电喷雾-离子阱质谱法推定硫酸依替米星中有关物质的结构

采用高效液相色谱-电喷雾-离子阱质谱法(HPLC-ESI-IT-MSn)对硫酸依替米星中有关物质结构进行推定.采用Phenomnex Gemini NX C18色谱柱,以水-氨水-冰醋酸(96∶ 3.6∶ 0.4, V/V)-甲醇(70∶ 30, V/V)为流动相,质谱条件:电喷雾离子源(ESI),正离子检测模式;离子源温度350 ℃;雾化氮气压力275.8 kPa;干燥氮气流速10 L/min;离子阱质谱检测器,Smart扫描模式,扫描质量范围m/z 100～900.硫酸依替米星样品中共检出18种有关物质,对其中的13种物质的结构进行了推定,其余5种有关物质的结构未进行解析,只提供了分子量和二级质谱信息.     

液相色谱-串联质谱测定纺织品中分散黄23和分散橙149

建立了高效液相色谱法(HPLC)和液相色谱-串联质谱法(LC-MS/MS)测定纺织品中分散黄23和分散橙149含量的方法.样品上的分散染料经氯苯蒸汽完全剥离纤维,浓缩后的残留物用甲醇定容,以0.1% H3PO4(或0.1%甲酸)和乙腈为流动相,经反相色谱柱分离后,用二极管阵列检测器(DAD)在420 nm处测定,并用电喷雾串联质谱确认.分散黄23和分散橙149的定量离子对分别为m/z 303/105和m/z 459/399.分散黄23和分散橙149的检出限(S/N=3):HPLC法为2.0和1.0 mg/kg,LC-MS/MS法都为1.0 μg/kg.HPLC在0.5～250 mg/L、LC-MS/MS在0.5～200 μg/L范围内,线性相关系数都大于0.995.方法的回收率在92.1%～98.7%之间,批间RSD都小于8.0%,含有分散黄23的阳性样品重复测试的RSD也小于8.0%.     

婴幼儿奶瓶中迁移双酚A的高效液相色谱-电喷雾串联质谱检测方法研究

建立了婴幼儿奶瓶中双酚A(BPA)迁移量的高效液相色谱-电喷雾串联质谱(HPLC-ESI-MS/MS)测定方法。奶瓶食品模拟浸泡液经过弗罗里硅土玻璃层析柱净化,高效液相色谱分离,采用选择反应性监测模式(SRM)检测。以一级质谱得到的准分子离子m/z 227作为母离子,进行二级质谱(MS2)分析。选择MS2的碎片离子m/z 212、133、93定性确证,m/z 212作为定量离子定量。实验优化了质谱条件,并对二级质谱碎裂机理和特征离子进行了研究。测定结果的相对标准偏差不大于8.2%(n=7),回收率在87.7%～105%之间;检出限为2μg/L,能够满足欧盟、美国等对奶瓶中双酚A的限制要求。该法已成功应用于婴幼儿奶瓶中BPA迁移量的测定。     

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.