气相色谱-质谱法测定蜡笔中的芳香伯胺

建立了固相萃取-气相色谱-质谱(SPE-GC-MS)检测儿童蜡笔中苯胺等9种芳香伯胺的方法。先用正己烷除去蜡笔中的烷烃类物质,再以甲醇为提取剂在室温下超声提取两次,提取液经过浓缩后与还原剂连二亚硫酸钠在70 ℃下反应30 min,将反应后的溶液通过硅藻土固相萃取柱净化收集,然后采用HP-5M色谱柱分离,并用质谱进行检测。采用该方法成功地实现了9种芳香伯胺的分离检测。对于不同的芳香伯胺的定量限为5 mg/kg,实际样品的平均回收率为86.02%～102.43%。实验结果证明,该方法准确、稳定,可以用于蜡笔中芳香伯胺的实际检验。     

固相萃取-气相色谱-质谱法测定儿童彩泥中的初级芳香胺

建立了固相萃取-气相色谱-质谱(SPE-GC-MS)检测儿童彩泥中苯胺等9种初级芳香胺的方法。对彩泥样品采用超声萃取法,以甲醇为提取剂于室温下反复提取2次,提取液经过浓缩后与还原剂溶液在70℃反应30 min,将反应后的溶液通过Oasis HLB固相萃取柱净化收集后进行检测。采用本方法成功实现了9种初级芳香胺的分离检测,方法的定量限为5 mg/kg,实际样品的平均回收率在70%～110%之间。本方法准确、快速、灵敏度高,可用于儿童彩泥中初级芳香胺的实际检验。     

固相萃取-气相色谱／质谱同时测定卷烟滤嘴中的四种芳香胺

采用固相萃取-气相色谱/质谱(SPE-GC/MS)法同时测定了卷烟抽吸后滤嘴中截留的1-氨基萘、2-氨基萘、3-氨基联苯和4-氨基联苯四种芳香胺.该法采用5%的盐酸超声振荡提取滤嘴中的芳香胺,提取液经液液萃取后进行衍生化和固相萃取,浓缩后进行GC/MS分析.1-氨基萘、2-氨基萘、3-氨基联苯和4-氨基联苯的检出限分别为0.51、0.42、0.18、0.18 ng/mL,相对标准偏差在0.94%～3.02%之间,回收率在92.67%～97.20%之间.该方法用于卷烟滤嘴中四种芳香胺的测定,结果发现不同材料的滤嘴对四种芳香胺有不同的截留作用.     

亲水作用色谱-串联质谱测定蔬菜中灭蝇胺及其代谢物三聚氰胺

建立了亲水作用色谱-串联质谱测定蔬菜中灭蝇胺及其代谢物三聚氰胺的方法.蔬菜样品匀浆后经甲醇-水提取,取适量酸化后提取液经阳离子固相萃取柱净化,洗脱液用氮气吹干,残留物用5 mL流动相定容.采用亲水作用色谱(Hilic)分离,在电喷雾-选择反应监测模式下,进行定性和定量分析.以基质校正曲线计算,添加浓度为0.04和0.20 mg/kg时,灭蝇胺的回收率为84.2%～101.3%; 相对标准偏差(RSD)为4.5%～10.7%;三聚氰胺的回收率为72.5%～97.1%; RSD为4.3%～10.8%;灭蝇胺和三聚氰胺的定量限分别为0.01和0.005 mg/kg.利用本方法检测了多种蔬菜样品中灭蝇胺、三聚氰胺的含量.     

3-氨基-9-乙基咔唑衍生化寡糖混合物的高效液相色谱分离及激光解吸电离飞行时间质谱分析

建立了以3-氨基-9-乙基咔唑(AEC)为衍生化试剂对寡糖的标记方法。寡糖的还原端与AEC的伯氨基反应生成烯胺,再被NaBH3CN还原为二级胺,使得寡糖被AEC标记。衍生物通过反相高效液相色谱分离纯化,采用的色谱柱为Waters Symmetry C18柱(3.9 mm×150 mm,5 μm),乙腈和乙酸铵水溶液(pH 4.5)为流动相,梯度洗脱,在254 nm波长处检测,并以基质辅助激光解吸电离飞行时间质谱进行分析。在此衍生化条件和色谱条件下,葡寡糖衍生物分离良好,并且AEC衍生可显著提高葡寡糖的质谱检测灵敏度。该方法适用于寡糖的分离纯化和结构分析,并与生物质谱具有良好的兼容性,表明该方法在微量寡糖链分析方面有广阔的应用前景。     

超高效液相色谱-线性离子阱/静电场轨道阱高分辨质谱鉴别纺织品中禁用芳香胺及其异构体

针对目前纺织品中禁用偶氮染料检测中的假阳性问题,建立了一套应用超高效液相色谱-线性离子阱/静电场轨道阱高分辨质谱（UPLC-LTQ/Orbitrap）同时筛选24种禁用芳香胺及其常见的14种异构体的方法。样品经连二亚硫酸钠还原,叔丁基甲醚提取后,以水/甲醇（9/1,v/v）稀释定容,用ZORBAX SB-C₁₈色谱柱（150 mm×2.1 mm,5 μm）分离,以0.1%甲酸水溶液和甲醇为流动相,电喷雾正离子（ESI⁺）模式电离。以准分子离子峰的精确质量数和保留时间定性,以提取的色谱图峰面积定量。38种芳香胺的线性相关系数大于0.99,方法检出限为0.5~5 μg/kg。该方法可通过一次实验同时对24种禁用芳香胺及其常见的14种异构体准确定性定量,大大缩短检测周期,实际样品检测也进一步验证了其灵敏性和准确性。     

超高效液相色谱-三重四极杆质谱法同时测定美术颜料中33种游离态初级芳香胺

建立了超高效液相色谱-三重四极杆质谱法(UPLC-MS/MS)同时测定水粉画颜料、油画颜料、丙烯画颜料等美术颜料中33种初级芳香胺(PAAs)的检测方法。样品中的初级芳香胺用乙腈提取,经离心分离、氮吹浓缩后,以甲醇-水(1:9, v/v)定容至2 mL, 0.22 μm膜过滤后上机检测。采用BEH Phenyl柱(100 mm×2.1 mm, 1.7 μm),以含0.07%(v/v)甲酸的甲醇溶液-水(1:9, v/v)为流动相,梯度洗脱分离,UPLC-MS/MS多反应监测模式(MRM)检测,同位素内标法定量。方法优化了色谱分离条件、质谱碎裂电压、碰撞能量等,并考察了提取时间、提取溶剂、浓缩方式等对回收率的影响。33种初级芳香胺的方法检出限为5~50 μg/kg,定量限为15~150 μg/kg, 3种不同基质样品在3个添加水平的平均回收率为70.1%~115.8%,相对标准偏差(RSD)为2.1%~15%。本方法操作简便、快速、准确、灵敏度高,能满足相关测定的要求。     

液相色谱/质谱法测定电气产品塑料部件中的初级芳香胺

采用高效液相色谱/质谱(HPLC-MS)法,对电子电气产品塑料部件中的26种初级芳香胺进行了同时测定.初级芳香胺用二氯甲烷、丙酮、甲醇等有机溶剂提取,然后浓缩提取液,用甲醇定容,最后用高效液相色谱/质谱联用仪分析检测.采用ZORBAX Eclipse XDB-C18色谱柱,流动相为乙腈-0.1%甲酸溶液,流速为0.6 mL/min,选择离子监测.26种禁用芳香胺的线性范围为0.1～10.0 mg/kg; r≥0.997; 检出限为0.05 mg/kg; 加标回收率为70%～110%; 相对标准偏差为0.23%～14.9%.结果表明, HPLC-MS法可以对塑料部件中的初级芳香胺进行定性定量测定.本研究选择离子色谱峰分离效果好,具有良好的稳定性和重现性.     

气相-质谱联用法测定主流烟气中几种芳香胺

采用固相萃取(SPE)-气相(GC)-质谱(MS)选择离子监测(SIM)法测定主流烟气中4种芳香胺(1-萘胺、2-萘胺、3-氨基联苯、4-氨基联苯)。探讨了萃取方式、萃取液浓度、萃取时间、pH等因素对分离检测的影响。对影响提取主流烟气中芳香胺的参数进行优化,在优化的条件下,用5%HCl在室温下超声萃取40 min,烟气中的芳香胺生成胺盐,用50%NaOH调胺盐pH至12以上,将胺游离出来。用五氟丙酸酐酰化,florisil SPE柱纯化后,上GC/MS检测。在优化的条件下,15 min内可实现4种芳香胺的分离检测。1-萘胺、2-萘胺、3-氨基联苯、4-氨基联苯的检测限分别为0.12、0.09、0.13、0.10 ng/mL,相对标准偏差在3.2%~4.7%之间;标准回收率在93.72%~104.22%之间,方法用于卷烟主流烟气中几种芳香胺的测定。     

高效液相色谱-质谱法测定电子电气产品塑料部件中偶氮染料释放的致癌芳香胺

采用高效液相色谱-质谱(HPLC-MS)法对电子电气产品塑料部件中偶氮染料还原裂解产生的21种芳香族伯胺进行同时测定。塑料用有机溶剂溶解或溶胀,释放其中存在的偶氮染料,在连二亚硫酸钠的强还原性环境中,偶氮染料被还原为芳香胺。用甲基叔丁基醚提取芳香胺,提取液浓缩后用甲醇-水(1：1,v/v)定容,HPLC-MS检测。采用ZORBAX Eclipse XDB C₁₈色谱柱分离,乙腈和0.1%(v/v)甲酸溶液为流动相,流速0.6 mL/min,选择离子监测(SIM)采集数据,色谱峰保留时间和特征离子定性。21种芳香胺的线性关系良好,r >0.998,方法检出限为0.5 mg/kg。除个别物质外,在空白塑料基质中的加标回收率为60.1%~129.5%,相对标准偏差小于14.0%。本研究表明电子电气塑料部件中的禁用偶氮染料还原产生的芳香胺能够被定性定量测定,本方法的准确度高,精密度好。     

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.     

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.     

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     

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...