分级净化结合气相色谱-质谱联用法测定豆芽中10种植物生长调节剂

建立了豆芽10种植物生长调节剂的分级净化体系,采用气相色谱质谱法(GC/MS)对该体系的效果进行了评价。豆芽先用酸性乙腈提取,浓缩后用甲醇复溶,部分经QuECHERS试剂盒净化后用GC/MS分析2,4-D-乙酯2,4-D-丁酯。另一部分经MCS固相萃取柱净化,先用5 mL甲醇洗脱得组分1,再用5%氨化甲醇洗脱得组分2;组分1浓缩后用10%三氟化硼甲醇溶液甲酯化,提取后GC/MS测定4-氯苯氧乙酸、α-萘乙酸、2,4-二氯苯氧乙酸、吲哚乙酸、吲哚丁酸,组分2浓缩后用GC/MS测定多效唑、激动素、6-苄基腺嘌呤。采用此净化体系对可以对不同性质的植物生长调节剂进行有效净化。结果表明,本方法完全可以用于豆芽中10种植物生长调节剂残留的检测,在豆芽中的添加0.01~0.1 mg/kg,10种植物生长调节剂平均回收率范围为70.5%~93.2%,RSD为5.2%~12.3%,本方法对10种植物生长调节剂的定量限(S/N≥10)为0.01~0.025 mg/kg,检出限(S/N≥3)为0.003~0.008 mg/kg。此净化体系简便、快速、准确,结合GC/MS可以满足豆芽中植物生长调节剂多残留检测要求。     

固相萃取-高效液相色谱法同时测定水果中4种植物生长调节剂

建立了固相萃取-高效液相色谱(HPLC)法同时测定水果中6-苄基腺嘌呤、噻苯隆、氯吡脲和烯效唑4种植物生长调节剂的方法。水果样品经乙腈提取,氨基固相萃取小柱净化后,于HPLC紫外检测器变波长检测。对6种水果进行添加回收试验,在0.04~0.4 mg/kg添加水平下,方法的回收率为73.1%~102.7%,相对标准偏差为0.8%~12%,方法的检出限(LODs)为0.005~0.01 mg/kg,定量限(LOQs)为0.015~0.03 mg/kg。     

高效液相色谱-串联质谱法同时测定5种鲜水果保鲜剂的残留量

建立了高效液相色谱-串联质谱法同时测定对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、2,4-二氯苯氧乙酸(2,4-D),乙萘酚和4-苯基苯酚5种鲜水果保鲜剂残留量的分析方法。样品经乙醚提取,固相萃取活性炭柱净化后,C18色谱柱分离,以乙腈和50%甲醇水为流动相进行梯度洗脱,电喷雾负离子(ESI-)模式电离,液相色谱-质谱法(LC-MS/MS)测定。结果表明:5种保鲜剂在0.05~1.2 mg/L范围内呈现良好的线性关系,相关系数(r2)均大于0.999,5种保鲜剂的检出限为0.5~20μg/kg。方法的加标回收率为81.0%~104.5%,相对标准偏差(RSD)为1.3%~6.8%。该方法简便快捷、灵敏度及准确性高,可满足鲜水果防腐保鲜剂残留量检测的要求。     

谷物中草毒死及草净津残留的高效液相色谱-串联质谱法同时测定

采用高效液相色谱-电喷雾电离-串联质谱(HPLC-ESI MS/MS)建立了同时测定谷物中草毒死、草净津残留量的分析方法。样品经二氯甲烷提取,Oasis HLB固相萃取柱净化,采用C18色谱柱(250 mm×4.6 mm i.d.,5μm)分离,甲醇-0.1%甲酸溶液(体积比50∶50)洗脱,ESI MS/MS进行测定。草毒死、草净津的线性范围分别为0.02~10.0、0.01~10.0 mg/kg,相关系数分别为0.999 6、0.999 3,检出限分别为0.01、0.005 mg/kg,平均加标回收率为80%~102%。     

超高效液相色谱-电喷雾串联四级杆质谱法快速测定烟草中8种植物生长调节剂残留

建立了超高效液相色谱-电喷雾串联质谱(UPLC-ESI-MS/MS)快速测定烟草中比久、多效唑、烯效唑、矮壮素、萘乙酸、2,4-D、赤霉素、脱落酸8种植物生长调节剂残留的检测方法。样品采用乙腈提取,经过C18分散吸附剂净化处理,采用ACQUITY UPLC?HSS T3柱(100×2.1mm,1.8μm),以甲醇-5mmol/L乙酸铵水溶液为流动相,梯度洗脱,电喷雾正负离子模式下分析检测,外标法定量。8种目标化合物在0.005~0.1mg/L范围内线性良好(R0.99),8种植物生长调节剂的检出限为1~4μg/kg,添加回收率为85.4%~103.1%,相对标准偏差为2.4%~6.2%。该方法简便快捷,灵敏准确,适合烟草中上述8种植物生长调节剂残留量的快速测定。     

固相萃取-超高效液相色谱-串联质谱法测定飞燕草中7种生物碱北大核心CSCD

建立了固相萃取技术(SPE)结合超高效液相色谱-串联质谱法(UPLC-MS/MS)同时测定飞燕草中7种生物碱的方法。采用单因素实验考察了固相萃取中各因素对飞燕草中7种生物碱萃取率的影响。最佳萃取条件为:乙醇作为提取溶剂,稀HCl调节pH值为6.0,PCX固相萃取柱净化,3%氨水甲醇溶剂洗脱。洗脱液采用ACQUITY UPLC BHEC_(18)柱(50 mm×2.1 mm×1.7μm),以乙腈-0.2%NH_(4)Ac为流动相进行UPLC-MS/MS分析,7种生物碱在1~100 mg/L范围内线性关系良好,相关系数均不低于0.982,检出限为0.02~0.45 mg/L,定量限在0.08~1.23 mg/L之间。样品中3个添加浓度水平(1、5、10 mg/L)回收率为95.9%~98.1%,相对标准偏差(RSD)不大于2.5%。采用该方法对6个产地的飞燕草进行了检测,样品中7种生物碱的含量在0.08~0.94 mg/g之间。结果表明,本文所建立方法准确性好,灵敏度高,操作简单快速,可满足飞燕草中生物碱检测的要求。     

固相萃取-高效液相色谱法测定果蔬中异菌脲残留量

建立了固相萃取-高效液相色谱法测定果蔬中异菌脲残留量的方法。样品用乙腈提取,C18固相萃取柱净化,甲醇-水(70:30,V/V)为流动相,经C18液相色谱柱分离,DAD紫外检测器(218 nm)检测。结果表明:异菌脲在0.1~2.0 mg/L范围内线性关系良好(R2=0.9998),方法定量限(以S/N=10计)为0.05 mg/kg,在0.05,0.1,0.5 mg/kg添加水平下的加标回收率范围为81.3%~98.3%,相对标准偏差(n=6)为3.9%~8.9%。方法适用于大多数水果、蔬菜中异菌脲残留量的测定。     

盐酸衍生-气相色谱法快速测定水果中苯丁锡残留

建立了水果中苯丁锡残留量测定的气相色谱法,并建立了气相色谱-质谱(EI源)确证方法。样品经二氯甲烷提取,浓盐酸衍生,酸性氧化铝柱固相萃取净化,正己烷-乙酸乙酯(9+1,V/V)洗脱,浓缩后通过气相色谱-电子俘获检测器进行测定。结果表明:方法的定量限为0.050 mg/kg,在0.05~5.0 mg/kg添加水平范围内,5种水果中苯丁锡的平均回收率在72.4%~98.4%之间,相对标准偏差不超过12%。     

稳定同位素内标/超高压液相色谱-串联质谱法同时测定水果与豆芽中10种植物生长调节剂残留

建立了水果与豆芽中10种植物生长调节剂残留的超高压液相色谱-串联质谱(UPLC-MS/MS)分析方法。以酸化乙腈(1∶1 000,体积比)为提取液,样品经高速匀浆与超声辅助分散提取后,提取液采用固相萃取柱净化,甲醇-5 mmol/L乙酸铵溶液为流动相,梯度洗脱,电喷雾电离,正负离子扫描,多反应监测模式(MRM)检测,基质匹配同位素内标标准曲线定量。最优条件下,10种植物生长调节剂残留在0.1~50.0μg/L浓度范围内线性关系良好,相关系数(r2)均大于0.995,检出限为0.2μg/kg,平均回收率为52.4%~119.6%,相对标准偏差(RSD)均小于13%。该方法样品前处理简单、净化效果好,同位素内标的使用解决了基质效应及前处理过程中待测物损失造成定量结果不准确的问题,适用于大批量果蔬中多种植物生长调节剂的快速测定。     

QuEChERS-超高效液相色谱串联质谱法同时测定土壤中5种常用除草剂

建立了超高效液相色谱串联质谱法(UPLC-MS/MS)简单、快速、灵敏、准确地同时测定土壤中5种常用除草剂多残留量的方法。样品经改进的QuEChERS(快速、简单、廉价、高效、灵活和安全)方法一步完成萃取净化,未使用缓冲盐溶液,经乙腈萃取,N-丙基乙二胺(PSA)和C18吸附剂填料净化,离心后直接过膜上机检测,萃取和净化的效果满足检测要求。UPLC-MS/MS方法采用Waters ACQUITY UPLCTMBEH C18(50 mm×2.1 mm i.d.,1.7 mm)色谱柱,柱温30℃,流动相为甲醇和水,梯度洗脱,流速0.25 mL/min,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式检测,外标法定量。5种常用除草剂在0.5~200 mg/L范围内线性关系良好,相关系数为0.9947~0.9984。在4和40 mg/kg水平下的平均加标回收率为75.4%~98.5%;相对标准偏差为3.2%~11.8%;方法的检出限(S/N=3)为0.005~0.020 mg/kg,定量限(S/N=10)为0.017~0.067 mg/kg。     

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.     

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     

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).     

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.     

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,使发光分子波长从可见光区(400~700 nm)延伸到近红外(NIR)区(700~1700 nm)。由于NIR发光分子在生物医学领域中的独特优势,其已成为目前AIE研究的热点。随着对NIR分子设计及应用的不断探索,附加不同功能且发光波长更长的AIE分子也被开发出来了,并实现了对生物体特定组织的NIR荧光成像、光声成像、光动力治疗和光热治疗等。本文总结了近年来具有AIE性能的NIR荧光分子的结构及其在生物医学领域的相关应用。     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.     

柴油加氢精制催化剂制备技术

柴油加氢精制催化剂制备技术的发展大致经历了3个阶段,由此形成了三代柴油加氢催化剂:单层分散的负载型金属硫化物催化剂,多层分散的负载型金属硫化物催化剂和非负载型金属硫化物催化剂。本文对金属硫化钼基柴油加氢精制催化剂的应用背景、制备思想及催化剂研究开发现状进行了系统的总结,对柴油加氢催化剂的发展方向进行了展望。     

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.