微波辅助微固相萃取-气相色谱/质谱法测定河水中5种有机磷农药

建立了一种微波辅助微固相萃取法,用于提取河水中的5种有机磷农药,用多壁碳纳米管做微固相萃取的吸附剂,对河水中的有机磷农药进行吸附,解析液用气相色谱/质谱法(GC-MS)分析。实验考察了提取温度、时间、解析溶剂的种类、解析时间对目标化合物峰面积的影响。确定最优的实验条件为:微波提取温度为70℃、提取时间为5min、乙酸乙酯为解析溶剂、超声解析的时间为10min。对加标的河水样品进行了分析,所得河水样品中被测物的回收率为94.3%~99.3%,相对标准偏差(RSD)为2.1%~5.9%。     

基于咪唑酯骨架结构材料-7的涡旋辅助微固相萃取

采用漩涡辅助微固相萃取的样品前处理方法,并结合高效液相色谱检测水样中的紫外吸收剂。沸石咪唑酯骨架结构材料-7(ZIF-7)具有大的比表面积,永久性孔道,开放的金属位点,以及较高的化学稳定性及水热稳定性,本文将ZIF-7作为固相萃取剂用于微固相萃取水样中的紫外吸收剂。实验考察了萃取剂用量、萃取时间、洗脱溶剂、洗脱时间、溶液pH值和盐浓度等对萃取效率的影响。最优实验条件为:ZIF-7的质量为15 mg,萃取时间是8 min,洗脱剂是甲醇∶乙腈(体积比3∶7),洗脱时间为5 min, NaCl溶液浓度为0 mg/mL,溶液pH为3。在此条件下,方法在2.5～750 ng/mL的范围内具有良好的线性,检出限为0.2～0.8 ng/mL,定量限为1.0～2.5 mg/mL。采用该方法分析实际水样中的紫外吸收剂,加标回收率为90.3%～111.5%,相对标准偏差为1.4%～7.2%,结果良好。     

磁性多壁碳纳米管固相萃取-气相色谱-质谱法检测水样中的13种邻苯二甲酸酯类化合物

建立了磁性多壁碳纳米管(MWCNTs)固相萃取结合气相色谱-质谱检测水样中13种邻苯二甲酸酯类化合物(PAEs)的方法。优化了萃取时间、水样pH值、解吸溶剂的种类和用量、解吸时间等影响萃取效率的主要条件。最终确定萃取时间为10 min,水样pH 5～7,解吸溶剂为2 mL丙酮,解吸时间为5 min。在优化的条件下,各组分的萃取回收率为89.7%～100.5%。方法具有较高的灵敏度,检出限(信噪比(S/N)为3)为0.08～0.47 μg/L。3种实际样品的加标回收率为84.5%～107.5%,相对标准偏差为1.9%～12.8%。该方法操作简便、省时,准确、灵敏、环保,可用于水样中PAEs的检测,并成功地应用于自来水、瓶装饮用水和湖水样品的分析,13种PAEs均未检出。     

茶叶中三氯杀螨醇残留量的微波萃取-固相微萃取-气相色谱快速检测方法

建立了微波辅助萃取-固相微萃取-气相色谱/电子捕获检测法快速测定茶叶中三氯杀螨醇的方法。采用自制的PDMS萃取头,优化了萃取溶剂的种类,微波辐射时间和微波功率等微波辅助萃取条件;研究了SPME萃取时间、搅拌速度、离子强度、解吸温度和解吸时间对萃取效率的影响。方法对三氯杀螨醇的检出限为0.048 ng/mL,线性范围为0.2~200 ng/mL。在优化的实验条件下,对乌龙茶进行添加回收试验,平均回收率为61.3%~72.8%,相对标准偏差为8.0%~16.3%。本方法适合于茶叶中痕量三氯杀螨醇快速检测。     

微波辅助-顶空液相微萃取/高效液相色谱分析水样中的邻硝基苯酚

建立了基于微波辅助-顶空液相微萃取在线联用、高效液相色谱法测定水样中邻硝基苯酚的分析方法。采用L16(45)正交实验设计对影响萃取的各种因素,如萃取有机溶剂、微波辐射功率、萃取时间、离子强度、样品液体积,进行了优化。优化后萃取条件为,以乙酸丁酯作为萃取溶剂,功率和时间分别为100W和12min条件下,离子强度为0的样品溶液体积为20mL。在优化萃取条件下,邻硝基苯酚的检出限LOD(S/N=3)为0.94μg/L,萃取富集倍数为30,实际水样的加标回收率为85.2%。理论分析和实验结果表明,微波辅助-顶空液相微萃取在线联用方法具有简便、快速、高效、节省溶剂、选择性好、应用范围广的特点。     

土壤中痕量水胺硫磷的微波辅助萃取-固相微萃取-GC-MS法测定

研究了微波辅助萃取(MAE)-固相微萃取(SPME)联合萃取、气相色谱-质谱法(GC-MS)测定土壤中水胺硫磷的分析方法；采用正交设计试验优化了微波升温程序、萃取温度、萃取时间、萃取溶剂体积等MAE条件；研究了SPME萃取涂层、萃取时间、解吸温度等对萃取效率的影响；方法的线性范围在1．O～20μg/L之间，检出限为O．49ng/g；测定25、100ng/g加标土壤样品，回收率分别为79％和107％。RSD分别为2．6％和6．5％；方法综合了MAE快速高效和SPME富集浓缩的优点，以水为萃取溶剂，特别适合于固体样品中痕量有机物的分析。     

镍钛合金表面离子液体掺杂聚苯基吡咯纤维涂层的制备及其对多氯联苯的高效固相微萃取

采用水热法和电沉积法在镍钛(NiTi)合金表面构筑1-丁基-3-甲基咪唑六氟磷酸盐离子液体(IL)掺杂聚苯基吡咯(PPPy)纤维涂层,成功制备了新型IL@PPPy-TiO_2/NiOCNSs固相微萃取(SPME)纤维。将该新型纤维与高效液相色谱(HPLC)联用,以多氯联苯(PCBs)、邻苯二甲酸酯(PAEs)、多环芳烃(PAHs)和紫外线(UV)吸收剂为模型分析物评价其萃取性能。结果显示,该纤维对PCBs有较强的萃取选择性和较高的萃取效率。在优化条件下,5种PCBs在一定质量浓度范围内呈良好线性,相关系数r≥0.998 6,检出限(LOD)为0.015～0.11μg/L。采用单支纤维在同日和隔日对50μg/L PCBs混合标准溶液进行萃取测定,相对标准偏差(RSD)分别为4.7%～6.1%和5.4%～7.0%,相同方法制备的5支纤维测定的RSD为6.5%～7.7%。实际水样的加标回收率为83.0%～104%,RSD不大于8.6%。所建立的SPME/HPLC法适用于不同环境水样中痕量PCBs的快速萃取和高效测定。     

聚(甲基丙烯酸-乙二醇甲基丙烯酸酯)微固相萃取-超高效液相色谱-串联质谱法测定水中雌激素

制备了聚(甲基丙烯酸-乙二醇甲基丙烯酸酯)有机聚合材料用于微固相萃取吸附剂,结合超高效液相色谱-串联三重四级杆质谱,建立了膜保护微固相萃取快速测定水体中E1、E2、E3、EE2和BPA 5种典型雌激素的方法。详细研究了萃取条件和解析条件对萃取效果的影响。在优化实验条件下,E3的检出限为0.2μg/L,线性范围为1～500μg/L,其余4种目标物检出限为0.02μg/L,线性范围为0.1～500μg/L。相对标准偏差均小于7.4%。方法用于实际污水处理厂污水中痕量雌激素的测定,样品加标回收率大于83%。     

固相微萃取-气相色谱-质谱法测定饮用水源中53种挥发性有机污染物

应用固相微萃取-气相色谱-质谱法测定饮用水源中53种挥发性有机污染物的含量。优化的试验条件如下:1萃取纤维为DVB/CAR/PDMS;2萃取温度为25℃;3顶空体积为9mL;4萃取时间为10min;5解吸温度为200℃;6解吸时间为3min。在气相色谱分离中用VF-624MS柱为固定相,在质谱分析中采用全扫描模式。53种挥发性有机污染物在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.001~0.130μg·L-1之间。方法用于实际水样的分析,加标回收率在75.9%~107%之间,测定值的相对标准偏差(n=5)在0.5%~18%之间。     

气相色谱-质谱法同时测定地下水中42种半挥发性有机污染物

建立了同时测定地下水中多环芳烃(PAHs)、多氯联苯(PCBs)、有机氯农药(OCPs)和有机磷农药(OPPs)等42种半挥发性有机污染物的分析方法,对固相萃取、液-液萃取、萃取溶剂和色谱柱等分析条件进行优化。最终采用乙酸乙酯-正己烷(1∶4)液液萃取,DB-5MS色谱柱分离,GC-MS/SIM测定,内标法定量。结果表明,42种目标物在0.5~1 000μg/L范围内线性关系良好(r20.995);方法检出限为0.05~3.08 ng/L。在10、40、400 ng/L加标水平下,42种目标物的基体加标平均回收率为73.0%~107%,相对标准偏差(RSD,n=5)为1.4%~11.3%。将方法应用于石家庄周边地区水样检测,结果可靠。该方法灵敏、准确、简单易行,可显著提高地下水中主要有机污染物的分析效率。     

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.     

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.     

Spectrophotometric study of Cd(II), Pb(II), Hg(II) and Zn(II) complexes with 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin

The reaction of 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP) with Cd(II), Pb(II), Hg(II) and Zn(II) was studied spectrophotometrically and kinetics, equilibrium constants as well as photodecomposition of complexes were determined. It was verified that these metal ions with large radius accelerate the incorporation reaction of zinc into TCPP. On the basis of the mechanism and kinetics of this reaction, a sensitive method for the spectrophotometric determination of trace amounts of Zn(II) has been developed. The molar absorptivity of examined Zn-TCPP complex and Sandell's sensitivity at 423 nm were 3.5×10⁵ M⁻¹ cm⁻¹ and 18.3 ng cm⁻². The detection limit for the recommended procedure was 1.4×10⁻⁹ M (0.9 ng ml⁻¹) and precision in range 20-100 ng ml⁻¹ not exceeds 2.7% RSD. The proposed method applied for zinc determination in natural waters and nutritional supplement was compared with AAS results and declared value.