固相萃取/在线热解吸-气相色谱法分析水样中苯系物

制备了Fe/Si O2/PDMS颗粒填充固相萃取柱,并建立了固相萃取/在线热解吸-气相色谱联用测定水样中痕量苯系物的分析方法。采用电磁感应加热技术在线热解吸固相萃取柱富集的苯系物,并直接引入气相色谱进样口进行分离定量。各苯系物在0.1~20 ng/L范围内线性关系良好,其相关系数(r)为0.999 2~0.999 6,对1 ng/L各苯系物测定的相对标准偏差(RSD,n=11)为2.0%~4.4%,检出限为0.03~0.05 ng/L。     

正交试验法优化制备用于小分子物质分离的聚(甲基丙烯酸缩水甘油酯-二乙烯基苯)型整体柱

以甲基丙烯酸缩水甘油酯(GMA)为单体,二乙烯基苯(DVB)为交联剂,以环己醇和正十二醇为致孔剂,过氧化苯甲酰(BPO)为引发剂,直接以50 mm×4.6 mm色谱柱为模具,通过原位聚合制备聚(GMA-DVB)型整体柱。以GMA和DVB的体积比、环己醇和十二醇的体积比以及BPO占聚合物的质量分数为三因素,以分离苯和乙苯等小分子物质时的半峰宽分离度(R1/2)为考察指标,进行三因素三水平的正交试验,通过测定整体柱的比表面积、孔径和孔容分布对其进行表征。结果表明,制备整体柱的最优配方为V(GMA): V(DVB): V(环己醇): V(正十二醇)=0.825:0.825:1.32:2.03, BPO的质量分数为0.7%。应用所制备的整体柱分离苯和乙苯等小分子物质,理论塔板数达到37000塔板/m, R1/2值达到7.14,完全达到基线分离,分离时间小于10 min。该方法制备整体柱的重复性好,柱效较高,基本满足商品化要求。     

新型二元致孔剂Pluronic F127/十二胺用于辛基杂化整体柱的合成与色谱性能评价

采用新型二元致孔剂Pluronic F127/十二胺,通过两步溶胶-凝胶法合成了辛基杂化整体柱,并用于稠环物质、苯系物以及水体中8种生物毒素的毛细管液相色谱分离分析.在整体柱的形貌方面,F127的加入使材料由聚集球状结构转变成双连续孔结构,并实现了对材料通孔、骨架以及骨架上介孔的尺寸调节,得到了更适于小分子分离的结构.此外,通过减少十二胺用量使凝胶化时间延长,显著降低了灌柱的难度以及灌柱时可能引起的材料不均匀和重复性差的问题.优化后的辛基杂化整体柱保持了良好的机械稳定性和高渗透性,塔板数为49000/m,与传统的制备方法相比柱效明显提高.在对稠环物质、苯系物等典型小分子的测试中均得到了良好的分离效果.新型二元致孔剂的辛基杂化整体柱制备更容易,形貌控制简单,稳定性好,实用性显著增强.     

β-环糊精衍生物/Cu_2O毛细管电色谱整体柱的制备及其应用

采用一步键合法制备了烯丙胺-β-环糊精/Cu_2O(Ally-β-CD/Cu_2O)毛细管电色谱整体柱,并考察了制备整体柱的主要影响因素。通过扫描电子显微镜(SEM)、X-射线光电子能谱(XPS)、X-射线衍射(XRD)对整体柱柱内固定相进行表征。以硫脲为中性标记物测定了柱效,柱效达到47 658 N/m。对D,L-组氨酸对映体的分离度RS达到3.82,整体柱在连续使用72h或间歇使用2个月后仍具有良好的分离能力,表明整体柱具有良好的重现性和稳定性,同时具备较好的手性拆分能力。运用该整体柱对盐酸克伦特罗对映体进行了拆分,达到基线分离,分离度达到2.89。     

纤维填充整体针式萃取装置的制备及其性能研究

建立了改善纤维填充整体针式萃取装置通透性和使用寿命的方法。将纤维纵向填充到内径为0.51 mm的不锈钢针里,以苯甲酸为模板分子,4-乙烯基吡啶(4-Vinyl pyridine,4-VP)为功能单体,乙二醇二甲基丙烯酸酯(Ethylene glycol dimethacrylate,EDMA)为交联剂,十二醇与甲苯为致孔剂,偶氮二异丁腈(Azobisisobutyronitrile,AIBN)为引发剂,采用原位聚合法制备纤维填充分子印迹整体针式萃取装置,该装置与气相色谱联用,考察其对苯系物的选择性萃取能力。结果表明,60束纤维填充萃取装置的萃取效果及通透性较好,且对汽油样品中少量的苯系物有良好的选择性,对苯系物的存储损失率也稳定在20%以内,萃取针的使用寿命可达60次,萃取效果好,相对标准偏差为2%~10%。     

一种毛细管电色谱整体柱的制备及其在CEC-MS中的应用

本研究以烯丙基咪唑鎓β-环糊精(AI-β-CD)为功能单体,乙二醇二甲基丙烯酸酯(EDMA)为交联剂,采用原位聚合法制备了一种毛细管电色谱整体柱。优化制柱条件,通过红外光谱和扫描电镜对整体柱固定相的结构和形貌进行表征。以D,L-酪氨酸为分析物对整体柱性能进行评价。结果表明,所制备固定相成功键合到毛细管内,并形成错综复杂的网状结构。同时该整体柱具有较强的对映体分离能力及稳定性。应用毛细管电色谱与质谱联用技术对手性除草剂甲氧咪草烟对映体进行分离,分离度为2.25。     

采用含原位聚合阴离子交换整体柱的微芯片分离氨基酸

采用原位聚合法,制备了以2-甲基丙烯酰氧乙基三甲基氯化铵(META)为功能单体的强碱性季铵盐离子交换型微整体柱,构建了带微整体柱的复合式微流控芯片;以氨基酸-H2O2-Lum inol化学发光体系为样品对象,根据氨基酸等电点的差异,在原位聚合微整体柱上进行分离实验。进行了苯丙氨酸-白氨酸、苯丙氨酸-组氨酸、苯丙氨酸-精氨酸3组氨基酸混合体系的分离,获得了很好的分离结果。优化并讨论了影响氨基酸分离效果的多种因素,如缓冲液pH值、洗脱液pH值和洗脱液流速等。在优化条件下,苯丙氨酸-精氨酸的分离度达到1.6,结果显示出整体柱与微流控体系相结合的可行性。     

气相色谱-质谱法测定汽车材料中7种苯系物

采用气相色谱-质谱法测定汽车材料中7种苯系物的含量。在气相色谱分离中用HP-5MS色谱柱为固定相,在质谱分析中采用全扫描和选择离子监测模式。以氘代苯-D6为内标物。7种苯系物的线性范围均为1 0~1 000ng,检出限(3s)在9~18ng之间。苯系物测定结果的相对标准偏差(n=6)在0.81%~2.4%之间,加标回收率在99.0%~102%之间。     

基于微气相色谱技术的快速检测系统

利用微细加工与MENS技术制造了一款微型气相色谱柱,在Pyrex型硼硅玻璃表面刻蚀出400μm的沟道,沟道总长度为5.8 m,均匀的以S形分布于硼硅玻璃芯片上。选用OV-17固定相对色谱柱进行涂敷,针对工业生产中排放的苯系物气体进行快速分离检测。设计了一整套的控制、采样、分离与检测系统,实现在线分离检测,选用灵敏度较高的PID(Photo Ionization Detector)光离子传感器作为终端检测器。精确的控制分离中的主要参数:温度与流量。针对分离苯系物气体混合物的特性,选取甲苯作为实验样本,通过温度与流量的变化实验找到最佳的分离条件参数。可以在10 min内对苯系物进行快速在线分析检测,对苯与甲苯等致癌气体的检测限达到0.523 mg/m~3和0.617 mg/m~3。     

手性金属-有机骨架材料{[Co(L-trp) (bpe)(H2O)]·U2O·NO3}n用于高效液相色谱的拆分性能

以L-色氨酸(L-trp)和1,2-二(4-吡啶基)乙烯(bpe)为配体与钴离子反应,通过水热法合成了一种具有二维手性层面结构的手性金属-有机骨架(MOFs)材料{[Co(L-trp)(bpe)(H2O)]·H2O· NO3}n;利用X射线粉末衍射(XRD)分析和扫描电子显微镜(SEM)对材料的结构和形貌进行了表征.将该MOFs材料用作固定相,制备了液相色谱手性柱,在正己烷/异丙醇的流动相体系下,考察了该手性柱对一系列手性化合物的拆分性能.实验结果表明,该手性柱对3种苯系物的位置异构体和11种外消旋化合物表现出较好的拆分性能.在正相色谱条件下,该手性柱表现出良好的重现性和稳定性.     

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.