液相色谱-电喷雾串联质谱同时检测血液中8种有毒生物碱

建立了高效液相色谱-电喷雾串联质谱同时检测血液中8种有毒生物碱的方法.血液样品经过乙酸铵-氨水缓冲溶液(pH≈9)处理后,以甲醇提取,采用电喷雾电离(ESI)、多反应监测(MRM)方式,可同时对麻黄碱、毛果芸香碱、士的宁、阿托品、钩吻素子、马钱子碱、乌头碱、喜树碱8种有毒生物碱进行定性和定量分析.在优化的条件下,上述前4种组分在1～100 μg/L范围内线性关系良好,后4种组分在2.5～500 μg/L范围内线性关系良好.8种有毒生物碱的提取回收率在83.1%～104.0%范围内.士的宁、阿托品、马钱子碱、乌头碱和钩吻素子检出限为0.05 μg/L,定量限为0.1 μg/L;麻黄碱、毛果芸香碱、喜树碱的检出限为0.1 μg/L,定量限为0.5 μg/L.各组分的日内RSD小于9%,日间RSD小于10%.本方法操作简便快捷、选择性好、灵敏度高,适用于中毒诊断和法医毒物分析.     

液相色谱-电喷雾串联质谱同时检测尿液和胃液中12种有毒生物碱

建立了高效液相色谱-电喷雾串联质谱同时检测尿液和胃液中12种有毒生物碱的方法.优化了提取条件及色谱-质谱条件,并考察了基质效应的影响,探讨了质谱碎裂机理.尿液和预先调节至中性的胃液经硼砂-NaOH缓冲液(pH 9.6)碱化,乙酸乙酯液液萃取,采用电喷雾电离(ESI+)、多反应监测(MRM)方式,可同时对黄华碱、倒千里光碱、山莨菪碱、钩吻碱、芦竹碱、哈尔碱、吐根碱、血根碱、吴茱萸碱、吴茱萸次碱、雷公藤吉碱和雷公藤次碱12种有毒生物碱进行定性和定量分析.在优化的条件下,12种成分分别在0.5～200 μg/L、1～200 μg/L和5～200μg/L范围内线性关系良好,尿液中除黄华碱和山莨菪碱外,各生物碱的回收率为61.9％～119.1％,胃液中各生物碱回收率为61,0％～1102％,精密度RSD＜ 15％.检出限(LOD)为0.1～0 Sμμg/L,定量限(LOQ)为0.5～5.0 μg/L,时回收率不高的生物碱可通过空白基质配制标样校正,满足定量分析的要求.本方法操作简便、快捷、灵敏度高,适用于中毒患者尿液和胃液中有毒生物碱成分的检测.     

分散液-液微萃取-气相色谱-质谱法同时测定中毒样品中有毒生物碱和鼠药

建立了分散液-液微萃取(Dispersive liquid-liquid micro-extraction,DLLME)与气相色谱-质谱(GCMS)联用同时测定中毒样品中3种鼠药(毒鼠强、溴鼠灵、溴敌隆)和5种有毒生物碱(莨菪碱、东莨菪碱碱、钩吻碱、士的宁、马钱子碱)的方法。100μL萃取剂氯仿与600μL分散剂甲醇混合后,迅速注入样品,萃取过程在乳化体系中完成;以8000 r/min离心5 min,使两相分层,取下层有机相进行GC-MS分析。考察了萃取剂、分散剂的种类和体积、萃取时间、pH值及盐浓度对萃取效率的影响。在优化条件下,各目标物在水样、尿样、黄酒样的检出限为0.003~1.0μg/L,在米饭样品检出限为0.002~0.2μg/kg;各目标物低、中、高加标回收率为81.0%~110%,精密度均小于7%。本方法灵敏度高,快捷高效,适用于中毒样品中有毒生物碱和鼠药的同时测定。     

钩吻素子的半合成

钩吻素子(Koumine)的新型笼状结构,引起了人们探讨其生源合成的兴趣。我们研究了从国产钩吻中分离出的7个已知结构的生物碱后,认为钩吻素戊(16-epi-nor-macusineB)可能是钩吻素子的前体。于是我们以手头所有的另一生物碱,老刺木碱(Vobasine)(在结构上与钩吻素戊同属于蛇根精(Sarpagine)类生物碱)为起始原料,先经LiAlH_4还原,再在稀硫酸中以SeO_2/H_2O_2氧化,同时发生骨架重排,完成了钩吻素子的半合成。其可能的机理如图所示:     

超高效液相色谱-串联质谱法测定化妆品中6种生物碱

建立了一种同时测定化妆品中6种生物碱(秋水仙碱、萝芙碱、藜芦定、西伐丁、麦角胺、麦角克碱)的超高效液相色谱-串联质谱分析方法。试样用0.1%甲酸-乙腈混合溶剂超声提取,Cleanert PCX固相萃取柱净化,经Thermo Hypersil GOLD色谱柱分离后在多反应监测模式下检测。结果表明:6种生物碱在0.2~20μg/L范围内线性关系良好(r20.999 0),方法定量下限为2.0~5.3μg/kg,3个加标水平下的平均回收率为83.9%~101.1%,相对标准偏差为0.7%~6.6%。该方法快速准确、灵敏度高,适用于化妆品中生物碱的安全性评价。     

固相萃取/超高效液相色谱-串联质谱法测定尿液中6种双酚类及烷基酚类物质

建立了超高效液相色谱-串联质谱测定人体尿液中双酚A(BPA)、双酚F(BPF)、四氯双酚A(TCBPA)、四溴双酚A(TBBPA)、壬基酚(NP)、4-正辛基苯酚(4-n-OP)的检测方法。尿液样品通过酶解和固相萃取法进行前处理,采用Acquity UPLC HSS T3色谱柱(2.1 mm×100 mm,1.8μm)分离,负离子电喷雾多反应监测模式检测,同位素内标法定量。6种待测物在0.5~50μg/L范围内线性关系良好,相关系数均大于0.995,检出限为0.05~0.60μg/L,定量下限为0.17~2.00μg/L,2、10、50μg/L加标水平下的回收率为81.4%~112%,相对标准偏差(RSD,n=6)为6.8%~30%。应用此方法测定160份人体尿液样品,双酚A的检出率为93.8%,检出范围为0.24~29.54μg/L,其余目标物未检出。该方法操作简便、重现性好、定量准确,适用于人体尿液中双酚类及烷基酚类物质的测定。     

钩吻生物碱的研究——Ⅰ.钩吻素己的结构

从国产钩吻(Gelsemium elegans Benth)中分得两种新生物碱,分别定名为钩吻素己(gelsenicine)和钩吻素庚(gelsenidine).钩吻素己的结构经测定证明为此外还获得六种已知生物碱:钩吻素子、卯,甲、丁,戊和N₁-甲氧基钩吻素甲,后者首次从国产钩吻中获得.钩吻素丁的分子式修正为C₂₁H₂₄N₂O₃,m. p.252～254℃(分解).用小鼠腹腔注射测定各生物碱的毒性,结果表明钩吻素已是迄今为止国产钩吻中毒性最大的生物碱,LD₅₀=18μg/kg.     

QuEChERS提取-超高效液相色谱-串联质谱法测定腐败人血中3种钩吻生物碱

为同时测定腐败血液中钩吻生物碱(钩吻素子、钩吻素甲和钩吻素己等3种),应用QuEChERS前处理方法提取上述3种分析物,并用超高效液相色谱-串联质谱法进行测定。取血样1.00mL,加入乙腈2mL和NaCl 50mg,涡旋振荡提取20s,继续振荡10min后,以8 000r·min~(-1)转速离心10min。取上清液,加入十八烷基硅烷(C_(18))20mg作为吸附剂,按上述相同方法振荡并离心,进行基质分散固相提取。取上清液按仪器工作条件进行分析。在色谱分离中,应用ZORBAX Eclipse Plus C18色谱柱为固定相和不同比例的(A)乙腈和(B)含φ0.1%甲酸的5mmol·L~(-1)甲酸铵溶液的混合溶液为流动相进行梯度淋洗,达到上述3种钩吻生物碱的良好分离。质谱测定中选择电喷雾正离子源和多反应监测模式。3种钩吻生物碱的质量浓度在一定范围内与对应的峰面积呈线性关系,检出限(3S/N)在0.005～0.1μg·L~(-1)之间。在空白血样的基础上加入上述3种钩吻生物碱的混合标准溶液,并按上述方法测定求得其回收率在90.5%～110%之间,测定值的相对标准偏差(n=6)在2.1%～5.1%。     

钩吻素子的晶体及分子结构

钩吻素子(Koumine)是钧吻生物碱(Kou-Wen Alkaloids)中的单体之一,其分子式为C_(20)H_(22)N_2O。它的晶体属单斜晶系,空间群为P2_1,晶胞参数为:α=8.422(0),b=13.209(1),c=7.881(1)A,β=108.201(9)°,V=834.995A~3;Z=2;D_c=1.29g/cm~3。 本文报道的钩吻素子是1981年Khuong-Huu F等人报导的钩吻素子的一个立体异构体,它们是钩吻素子的两个非对映体旋光异构体。     

钩吻生物碱 Ⅰ.国产钩吻生物碱再研究和钩吻素子的构造

1.重研究了国产钩吻生物碱,比较和改良这些生物碱的提取方法.除获得前人曾经报告的钩吻素子、钩吻素卯和钩吻素甲以外,还得到了两种新的次要生物碱,钩吻素丁和钩吻素戊,但未得钩吻素丙和钩吻素辰.钩吻素丁熔点232-234°,实验式暂定为C_(26)H_(30)N_2O_4;钩吻素戊熔点202-204°,实验式暂定为C_(19)H_(22)N_2O;从紫外光谱推断,二者都是吲哚类型的生物碱.并修正钩吻素卯的实验式为C_(20)H_(26)N_2O_4,从紫外及红外光谱初步推测,它可能是一种内盐式的假吲哚类型生物碱. 2.对国产钩吻中的主要生物碱钩吻素子的化学结构作了初步解析.从光谱及化学证据推断,钩吻素子与钩吻素甲具不同的发色系统,前者属于假吲哚型,而后者已知是属于2-氧吲哚型的.虽然这两种生物碱都含环外乙烯基,N_b-甲基及可能具环醚结构,但是其脂环部分的构造按推断亦不相同.     

Gels from a semifluorinated n-alkane in fluorinated solvents as a probe for intermolecular interactions

Diblock semifluorinated n-alkanes can form aggregates and gels in fluorinated solvents. We have investigated the thermal behavior of binary mixtures comprising F(CF₂)₈(CH₂)₁₆H and fluorinated solvents. The solvents were perfluorohexane, perfluoroheptane, perfluorooctane, perfluorooctyl bromide, perfluorodecalin, and perfluorotributylamine. The phase diagrams were used to calculate the activity coefficients of the two components and the main excess thermodynamic functions. The solubility and self-assembly behavior of F₈H₁₆ in the fluorinated solvents are related to the different solute–solvent dispersion interactions that depend on the polarizabilities and ionization potentials of the interacting species, and on the structural properties of the solvent.     

HCOO在Cu(110)、Ag(110)和Au(110)表面的吸附

采用密度泛函理论(DFT)以及广义梯度近似方法(GGA)计算了甲酸根(HCOO)在Cu(110)、Ag(110)和Au(110)表面的吸附. 计算结果表明, 短桥位是最稳定的吸附位置, 计算的几何参数与以前的实验和计算结果吻合. 吸附热顺序为Cu(110)(-116 kJ·mol-1)>Ag(110)(-57 kJ·mol-1)>Au(110)(-27 kJ·mol-1), 与实验上甲酸根的分解温度相一致. 电子态密度分析表明, 吸附热顺序可以用吸附分子与金属d-带之间的Pauli 排斥来关联, 即排斥作用越大, 吸附越弱. 另外还从计算的吸附热数据以及实验上HCOO的分解温度估算了反应CO2+1/2H2→HCOO的活化能, 其大小顺序为Au(110)>Ag(110)>Cu(110).     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性;均苯四甲酸二酐;联苯四羧酸二酐;二羟基联苯胺;聚酰亚胺;聚苯并噁唑;耐热性     

Studies on the Formation of Catalytically Active PGM Nanoparticles from Model Solutions as a Basis for the Recycling of Spent Catalysts

The paper presents basic studies on the precipitation of platinum, palladium, rhodium, and ruthenium nanoparticles from model acidic solutions using sodium borohydride, ascorbic acid, and sodium formate as reducing agents and polyvinylpyrrolidone as a stabilizing agent. The size of the obtained PGM particles after precipitation with NaBH₄ solution does not exceed 55 nm. NaBH₄ is an efficient reducer; the precipitation yields for Pt, Pd, Ru, Rh are 75, 90, 65 and 85%, respectively. By precipitation with ascorbic acid, it is possible to efficiently separate Pt, Rh, and Ru from Pd from the two-component mixtures. The obtained Pt, Pd, and Rh precipitates have the catalytic ability of the catalytic reaction of p-nitrophenol to p-aminophenol. The morphological characteristic of the PGM precipitates was analyzed by AFM, SEM-EDS, and TEM.     

Direct Quantitation of Phytocannabinoids by One-Dimensional 1H qNMR and Two-Dimensional 1H-1H COSY qNMR in Complex Natural Mixtures

The widespread use of phytocannabinoids or cannabis extracts as ingredients in numerous types of products, in combination with the legal restrictions on THC content, has created a need for the development of new, rapid, and universal analytical methods for their quantitation that ideally could be applied without separation and standards. Based on previously described qNMR studies, we developed an expanded ¹H qNMR method and a novel 2D-COSY qNMR method for the rapid quantitation of ten major phytocannabinoids in cannabis plant extracts and cannabis-based products. The ¹H qNMR method was successfully developed for the quantitation of cannabidiol (CBD), cannabidiolic acid (CBDA), cannabinol (CBN), cannabichromene (CBC), cannabichromenic acid (CBCA), cannabigerol (CBG), cannabigerolic acid (CBGA), Δ9-tetrahydrocannabinol (Δ9-THC), Δ9-tetrahydrocannabinolic acid (Δ9-THCA), Δ8-tetrahydrocannabinol (Δ8-THC), cannabielsoin (CBE), and cannabidivarin (CBDV). Moreover, cannabidivarinic acid (CBDVA) and Δ9-tetrahydrocannabivarinic acid (Δ9-THCVA) can be distinguished from CBDA and Δ9-THCA respectively, while cannabigerovarin (CBGV) and Δ8-tetrahydrocannabivarin (Δ8-THCV) present the same ¹H-spectra as CBG and Δ8-THC, respectively. The COSY qNMR method was applied for the quantitation of CBD, CBDA, CBN, CBG/CBGA, and THC/THCA. The two methods were applied for the analysis of hemp plants; cannabis extracts; edible cannabis medium-chain triglycerides (MCT); and hemp seed oils and cosmetic products with cannabinoids. The ¹H-NMR method does not require the use of reference compounds, and it requires only a short time for analysis. However, complex extracts in ¹H-NMR may have a lot of signals, and quantitation with this method is often hampered by peak overlap, with 2D NMR providing a solution to this obstacle. The most important advantage of the COSY NMR quantitation method was the determination of the legality of cannabis plants, extracts, and edible oils based on their THC/THCA content, particularly in the cases of some samples for which the determination of THC/THCA content by ¹H qNMR was not feasible.     

Transition metal complexes of the tripodal ligand 4-(2′-pyridylmethyl)-4-azaheptane-1,7-diamine. Crystal structures of [CuLCl]ClO4 and [NiL(MeCN)2](ClO4)2

The tripodal ligand 4-(2′-pyridylmthyl)-4-azaheptane-1,7-diamine has been prepared by reaction of 2-aminemethyl pyridine with acrylonitrile, followed by the reduction of the nitrile groups. Copper(II), nickel(II), zinc(II), cobalt(III) and chromium(III) complexes of the ligand have been prepared and characterized and the crystal structures of the complexes [CuLCl]ClO₄ and [NiL(MeCN)₂](ClO₄)₂ determined. The copper complex is five coordinate with approximate square pyramidal stereochemistry with the apical position occupied by a primary amine donor. The nickel complex is octahedral with the pyridine nitrogen donor lying trans to an acetonitrile ligand.     

SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES WITH AMPICILLIN

Abstract

The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]₂ × nH₂O (n = 1.5?3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.     

Magnetism of metal-nitroxide compounds involving bis-chelating imidazole and benzimidazole substituted nitronyl nitroxide free radicals

Coordination compounds based on imidazole and benzimidazole substituted nitronyl nitroxide radicals with transition metal ions and trivalent lanthanide ions are described from the perspective of their magnetic properties.For the transition metal compounds the crystal structures show various metal-nitroxide dimensionalities including mononuclear (0D), one-dimensional (1D) and two-dimensional (2D) complexes. The mononuclear complexes were isolated with most metal ions of the first transition series. One copper(II) complex shows a copper(II)-radical ferromagnetic coupling (J = +75 cm⁻¹) while for the other mononuclear compounds, mainly with manganese(II), the metal-radical interactions are antiferromagnetic. The one-dimensional and two-dimensional complexes are manganese(II) compounds which show canting effects leading to weak ferromagnetism.For the trivalent lanthanide ions [La(III), Gd(III) and Eu(III)], three series of mononuclear complexes were obtained in which the metal center is bound to four, two or one nitroxide radicals depending on the counter ions and ancillary ligands. Unexpectedly, in most gadolinium(III) complexes, the Gd(III)-radical interactions were found to be antiferromagnetic in contradiction with other foundings and previous theoretical models. In support to the magnetic studies, the optical properties of the lantanide complexes have also been investigated and are briefly described.     

New Complexes of Ditopic Ligands with “d” and/or “s” Metal Ions

Abstract

The asymmetric compartmental macrocycles containing one N₂O₂ or N₃O₂ Schiff base and one O₂O₃ or O₂O₄ crown-ether like chamber, have been obtained by condensation reaction of the formyl precursors 3,3′-(3-oxapentane-1, 5-diyldioxy) bis (2-hydroxybenzaldehyde) or 3,3′-(3,6-dioxaoctane-1,8-diyldioxy)-bis(2-hydroxybenzaldehyde) with ethyl ethylenediamine (H₂L_A, H₂L_C), 1,5-diamino-3-azamethylpentane(H₂L_B, H₂L_D), also in the presence of metal ions as templating agents. These ditopic ligands, with dissimilar coordination sites, have been designed and used for the selective complexation of “d” and/or “s” metal ions, respectively into the Schiff base and the crown ether chamber. The selectivity of these processes strongly depends on the size and on the donor atom sets of the sites. The possibility to obtain mononuclear M(L)·nH₂O (M = Ni²⁺, Cu²⁺, Co²⁺), Mn(L)(CH₃COO)·nH₂O or Na(L) and hetero-dinuclear MNa(L)(CH₃COO) (M = Ni²⁺, Cu²⁺, Co²⁺) and MnNa(L)(CH₃COO)₂·nH₂O complexes has been successfully tested. The ligands and complexes have been characterized by ir, nmr, mass spectrometry and magnetic susceptibility measurements.

Two of the ligands used for the preparation of the solid samples, i.e., to H₂L_A and H₂L_B, have been employed to study complexation reactions of Co(II) and Na(I) in solution. In order to obtain information on the ligand preorganization effect toward the complex stabilities, a simpler open chain parent compound of H₂L_B (H₂L_E) has been also prepared and studied. FT-IR spectra show that H₂L_A is unable to complex Na⁺ in DMSO while the complexation reactions of Na⁺ by H₂L_B and of Co²⁺ by H₂L_A take place with slow kinetics. Therefore, thermodynamic data have been obtained only for the systems Co²⁺/H₂L_B and Co²⁺/H₂L_E. The thermodynamic parameters obtained for the complexation reactions show that the pre-organization of the donor atoms in H₂L_B does not add a significant contribution to the stabilities of the complexes. Both H₂L_B and H₂L_E form in DMSO 1:1, 1:2 and 1:3 = M:L complexes with very similar stabilities and almost equal enthalpies of formation. Physico-chemical studies suggest besides that the slow reaction of Na⁺ with H₂L_B is probably due to the formation of a 1:1 complex where the metal cation, initially occupying the O₃ cage of the ligand, slowly binds also the oxygens of the phenolic moieties. Spectral and calorimetric data on solutions containing H₂L_B and different Co²⁺: Na⁺ ratios evidence that in DMSO no stable heterodinuclear complexes form when the neutral ligand is considered.     

具有聚集诱导发光性质的近红外荧光染料

聚集诱导发光(AIE)现象的发现为解决传统有机荧光分子在高浓度和聚集形态下存在的荧光猝灭问题提供了最佳方案,并实现了在光电器件、化学传感、生物成像和靶向治疗等众多领域的广泛应用.随着对AIE 发光机理研究的不断深入,AIE 分子体系得到了极大的扩展.其中,一类具有给体-受体结构的AIE分子能够显著降低分子能隙,使发光分...