气相色谱法测定水中四种菊酯类农药的残留量

建立了一种生活饮用水与水源水中菊酯类农药残留量的气相色谱检测方法.以石油醚为萃取剂,利用PE-5毛细管色谱柱分离,用GC-ECD测定联苯菊酯、甲氰菊酯、氯氰菊酯、溴菊酯四种拟虫类菊酯农药的残留量.方法的线性范围0.08～0.4tg·mL-1,相对标准偏差为3.7％～9.5％,加标回收率为80.2％～108.5％.方法准确、灵敏、可靠,且有机溶剂用量小,验证了方法的实用性.     

四种拟除虫菊酯的超临界色谱手性分离

获得低毒高效的单一对映体对于发挥农药活性和环境安全具有重要意义.使用超临界CO2色谱,对4种拟除虫菊酯在Chiralcel OD-H柱上进行对映体分离研究,并考察了改性剂种类及体积分数对其分离的影响.高效氯氟氰菊酯在1％甲醇改性时得到完全分离(R1-2=2.74,R2-3=1.56,R3-4=4.74);氯菊酯在3％异丙醇改性时分离得到3个色谱峰(R1-2=1.62,R2-3=1.01);联苯菊酯不能实现手性分离;氯氰菊酯在1％乙醇改性时得到5个色谱峰(R1-2=3.30,R2-3=1.84,R3-4=2.57,R4-5=0.93).拟除虫菊酯的分离效果与化合物分子结构密切相关.     

拟除虫菊酯的分子设计与合成

设计并制备了两种用作合成拟除虫菊酯的中间体－α－甲基肉桂醇和溴代异丙叉丙酮,分别与第一菊酸酯化,得到两种新型的拟除虫菊酯。并经初步测试,这两种菊酯均具有较强的杀虫活性,且与天然除虫菊素相比,分子量减小,蒸气压升高,能在不加热的条件下自然挥发,增强药效。     

宽口径毛细管气相色谱法同时测定蔬菜中多种拟除虫菊酯农药残留量

建立了一种同时测定蔬菜中7种拟除虫菊酯类农药残留的气相色谱方法.利用丙酮提取,活性炭脱色,弗罗里硅土填料净化,采用宽口径石英毛细管柱同时测定蔬菜中联苯菊酯、甲氰菊酯、三氟氯氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯及溴氰菊酯残留量.结果表明,最小检测限为0 003～0 013mg/kg,回收率在78 9%～113%之间,变异系数在2 0%～12%之间(n=5).证明本方法分离效果好,灵敏度、准确度和精密度高,线性关系良好,可以满足无公害蔬菜农药残留标准的检测要求.     

联苯菊酯对靶标生物及非靶标生物毒性的对映体差异

拟除虫菊酯类杀虫剂因高效、低毒、易生物降解等特性而比有机氯、有机磷类杀虫剂使用更为广泛.早期研究已有很多报道关于拟除虫菊酯在水体生物中的对映体选择性毒性,但在拟除虫菊酯对靶标生物及非靶标生物毒性的对映体差异上的研究还鲜有报道.实验研究了联苯菊酯对靶标生物菜青虫Pieris rapae L.和以HepG2细胞为模型的非靶标生物毒性的对映体选择性差异,结果表明对靶标生物菜青虫1R-cis-BF比1S-cis-BF的毒性强300倍以上;而对以HepG2细胞为模型的非靶标生物,染毒质量浓度在7.5 mg/L以上1S-cis-BF的毒性大于1R-cis-BF(p＜0.05).实验为从对映体水平上研究手性农药对靶标生物及非靶标生物的对映体选择性及研究更为安全有效的农药提供了参考和依据.     

宽口径毛细管气相色谱法同时测定蔬菜中多种拟除虫菊酯农药残留量

建立了一种同时测定蔬菜中7种拟除虫菊酯类农药残留的气相色谱方法。利用丙酮提取，活性炭脱色，弗罗里硅土填料净化，采用宽口径石英毛细管柱同时测定蔬菜中联苯菊酯、甲氰菊酯、三氟氯氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯及溴氰菊酯残留量。结果表明，最小检测限为0．003～0．013mg/kg，回收率在78．9％～113％之间，变异系数在2．0％～12％之间(n=5)。证明本方法分离效果好，灵敏度、准确度和精密度高，线性关系良好，可以满足无公害蔬菜农药残留标准的检测要求。     

几种固定化耐冷菌载体的比较研究

向低温污水中投加耐冷菌,污水中有机物的去除率可大幅提高,但菌体流失快,重复使用性差.结合吸附法与包埋法,对聚胺脂泡沫、破碎陶粒、柱状活性炭等几种载体进行生物固定化,形成生物载体.实验结果表明固定化生物载体的效果取决于载体的孔径及表面的粗糙程度,载体固定化效果为:聚胺脂泡沫>陶粒>活性炭.经过60d 的连续运行,载体上的耐冷菌的活性良好且有大量的增殖,生物载体对污水中有机物的去除效果为:聚胺脂泡沫>陶粒>活性炭.     

除虫菊酯的快速气相色谱分析

用气相色谱法同时快速定量测定丙烯菊酯,胺菊酯和氯氰菊酯等除虫菊酯的混合物。采用色谱柱为５％ ＯＶ－１０１ Ｃｈｒｏｍｏｓｏｒｂ Ｗ ＨＰ,氢火焰离子化检测器。     

氯菊酯和联苯菊酯的高效液相色谱手性分离

采用高效液相色谱法,在纤维素衍生物手性固定相柱上直接拆分氯菊酯和联苯菊酯,分别得到完全分离的4个氯菊酯异构体和2个联苯菊酯异构体的色谱峰,探讨了不同流动相比例及不同温度对分离结果的影响。结果显示,在流动相比例为正己烷:乙醇=99:1,柱温为25°C的色谱条件下,氯菊酯的4个对映异构体中相邻峰的分离度均达到1.4以上,联苯菊酯的分离度达到2.0以上。     

苯酚类毒物的毒性研究

文章应用生物法 (大型蚤 )测试了一系列苯酚取代物的急性毒性值 ,LC50(48h) ,并对测试结果作了定量构～活关系 (QSAR)分析。证明取代物的毒性按下列顺序减小 :-CH3 > -X>-OH> -NH2 > -NO2>> -OH(苯酚)     

Thermodynamic study on reaction path of Hg（ II ） with S（ II ） in solution

The mercury sulfidation experiments were conducted in the pH range from 1 to 13. The results show that Hg(Ⅱ) reacted with equimolar S(Ⅱ) has the lowest remained Hg(Ⅱ) concentration (9.7 μg/L) at pH 1.0 and the highest remained concentration (940.8 ug/L) at pH 13.0. Meanwhile, the changes of pH values were monitored exactly, which reveal that solution pH values change when mixing the same pH value solutions of HgCl_2 and Na_2S. In order to explain the phenomena and determine the reaction paths of Hg(Ⅱ) reacting with S(Ⅱ) in the solution, the concerned thermodynamics was studied. Species of S(Ⅱ)-H_2O system and Hg(Ⅱ)-H_2O system at different pH values were calculated, and then the species distribution diagrams of S(Ⅱ)-H_2O system, Hg(Ⅱ)-H_2O system and Hg(Ⅱ)-Cl~-0H~~-H_2O system were drawn. Combining the experimental data and thermodynamic calculation, the mechanism of Hg(Ⅱ) reacting with S(Ⅱ) was deduced. The results indicate that different species of S(Ⅱ) and Hg(Ⅱ) have the diverse reaction paths to form HgS precipitate at different pH values and the standard Gibbs free energies change(△_rG_m~Θ) of those equations are also calculated, which can provide a guidance for mercury-containing wastewater treatment with Na_2S.     

Optoelectronic properties of new functionalized heteroleptic iridium complex

A new functionalized heteroleptic iridium complex coordinated with 1-phenylisoquinoline(1-piq) and a functionalized β-diketone(G1),Ir(1-piq)2G1,was synthesized and characterized by 1H-NMR,mass spectrometry and elemental analysis.The larger conjugation of the replacement of acetylacetone(acac) by a functionalized β-diketonate ligand led to a significant decrease in the HOMO level toward vacuum level,while Ir(1-piq)2G1 and Ir(1-piq)2(acac) showed red phosphorescent emissions of about 620 nm in dichloromethane...     

古建筑榫卯节点加固方法振动台试验研究

为保护古建筑,采用振动台试验方法,研究了中国古建筑榫卯节点的有效抗震加固方法。基于某古建筑的实际尺寸,制作了1∶8缩尺比例的木结构空间框架模型,其中梁和柱采用燕尾榫形式连接。分别考虑马口铁、钢构件和CFRP布加固榫卯节点,进行了振动台试验。通过白噪声激励,获得了构架加固前后的基频及阻尼比;通过输入不同加速度峰值的El-Centro波,获得了典型节点的位移响应、加速度响应及减震系数等抗震参数。结果表明,构架加固前后的基频J(钢构件)>J(CFRP布)>J(马口铁)>J(未加固);阻尼比D(未加固)>D(马口铁)>D(钢构件)>D(CFRP布);构架位移响应峰值umax(CFRP布)相似文献   

Syntheses and applications of Eu（Ⅲ） complexes of 2-thienyltrifluoroacetonate, terephthalic acid and phenanthroline as light conversion agents

A series of europium(Ⅲ) complexes of 2-thienyltrifluoroacetonate (HTTA), terephthalic acid (TPA) and phenanthroline (Phen) were synthesized. The new complexes Eu(TPA)(TTA)Phen and Eu2(TPA)(TTA)4Phen2 were characterized by elemental analysis, IR spectrum, scanning electron microscope and thermal stability analysis. The results show that the thermal stability of the Eu( Ⅲ ) complexes increases in the following order: the mononuclear complex Eu(TTA)3Phen, the binuclear complex Eu2(TPA)(TTA)4Phen2, the chain polynuclear complex Eu(TPA)(TTA)Phen. And the formation of the binuclear/polynuclear structure of the new complexes appears to be responsible for the enhancement of their thermal and optical stability. In addition, The fluorescence excitation spectra of these new complexes show more broad excitation bands than that of the complex Eu(TTA)3Phen corresponding to their formation. The enhancement of Eu3 fluorescence in the new complexes can be observed by the addition of Gd3 . The bright red luminescent plastics can be obtained when the complex EuGd(TPA)(TTA)4Phen2 is added above 0.5% (mass fraction).     

Synthesis and characterization of arsenate antimonic acid AAAc(1 : 1)

The AAAc(1 : 1) was synthesized in water by As₂O₃ and Sb₂O₃ with molar ratio of 1 : 1. AAAc(1 : 1) was characterized by Raman, IR, TG/DTG, DSC, XPS and XRD. The results show that there are four peaks to v _s of As-OH, As-O-Sb, Sb-OH and Sb-O-Sb in Raman spectra of AAAc(1 : 1) at 100 – 1 000 cm⁻¹. The solution of AAAc(1 : 1) was also titrated with KOH solution. The titration results show that AAAc(1 : 1) is a hexabasic acid with dissociation constants of k ₁=3.62 × 10⁻², k ₂=3.05 × 10⁻³, k ₃=6.43 × 10⁻⁶, k ₄ =9.78 × 10⁻⁸, k ₅=1.32 × 10⁻¹¹, k ₆=3.87 × 10⁻¹². AAAc(1 : 1) has a good solubility and stability in water, its solid obtained by free volatilizing water from its solution under air at ambient temperature is amorphous. Chemical and thermal analysis show that the composition of AAAc(1 : 1) is As₂O₅ · Sb₂O₅ · 8H₂O in air at 25 °C. AAAc(1 : 1) has the structure of AsO(OH)₂-OH-Sb(OH)₄-O-Sb(OH)₄-OH-AsO(OH)₂ or As(OH)₃-O-Sb(OH)₄-O-Sb(OH)₄-O-As(OH)₃ (isomerism) through experimental determination and geometry optimization. Foundation item: Project(50274075) supported by the National Natural Science Foundation of China     

The Quantum Chemistry Calculation and Thermoelectrics of Bi-Sb-Te Series

The density function theory and discrete variation method ( DFT- DVM ) was used to study correlation between composition, structure, chemical bond, and property of thermoelectrics of Bi-Sb-Te series. 8 models of Bi2o-xSbxTe32( x = 0,2,6,8,12, 14,18 and 20) were ca/zulated. The resu/ts show that there is less difference in the ionic bonds between Te(I)-Bi( Sb ) and Te(Ⅱ)-Bi( Sb ) , but the covalent bond of Te( I )-Bi( Sb ) is stronger than that of Te(Ⅱ)-Bi( Sb ). The interaction between Te( I ) and Te( I ) in different layers is the weakest and the interaction should be Van Der Waals power. The charge of Sb is lower than that of Bi , and the ionic bond of Te- Sb is weaker than that of Te- Bi . 7he covalent bond of Te- Sb is also weaker than that of Te-Bi. Therefore, the thermoelectric property may be improved by adjusting the electrical conduaidty and thermal conductivity through changing the composition in the compounds of Bi-Sb- Te. The calculated results are consistent with the experiments.     

Structural characteristics and properties of polyurethane modified TDE-85/MeTHPA epoxy resin with interpenetrating polymer networks

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate（TDE-85）/methyl tetrahydrophthalic anhydride （MeTHPA） epoxy resin was modified with polyurethane（PU） and the interpenetrating polymer networks（IPNs） of PU-modified TDE-85/MeTHPA resin were prepared. The structural characteristics and properties of PU-modified TDE-85/MeTHPA resin were investigated by Fourier transform infrared（FTIR） spectrum,emission scanning electron microscopy（SEM） and thermogravimetry（TG）. The results indicate that epoxy polymer network （Ⅰ） and polyurethane polymer network （Ⅱ） of the modified resin can be obtained and the networks （Ⅰ） and （Ⅱ） interpenetrate and tangle highly each other at the phase interface. The micro morphology presents heterogeneous structure. The integrative properties of PU-modified TDE-85/MeTHPA epoxy resin are improved obviously. The PU-modified TDE-85/ MeTHPA resin’s tensile strength reaches 69.39 MPa,the impact strength reaches 23.56 kJ/m,the temperature for the system to lose 1% mass （t1%） is 300 ℃,and that for the system to lose 50% mass （t50%） is 378 ℃. Compared with those of TDE-85/MeTHPA resin,the tensile strength,impact strength,t1% and t50% of the PU-modified resin increases by 48%,115%,30 ℃,11 ℃,respectively. The PU-modified TDE-85/MeTHPA resin has the structure characteristics and properties of interpenetrating polymer networks.     

Kinetics,thermodynamics, and equilibrium of As(III), Cd(II), Cu(II) and Pb(II) adsorption using porous chitosan bead-supported MnFe2O4 nanoparticles

A novel porous nanocomposite, cross-linked chitosan and polyethylene glycol (PEG) bead-supported MnFe₂O₄ nanoparticles (CPM), was developed as an efficient adsorbent to remove metalloid (As(III)) and heavy metals (Cd(II), Cu(II), and Pb(II)). The characteristics of CPM showed a porous structure, well dispersed MnFe₂O₄, and several of hydroxyl and amino groups (OH, NH₂). Batch experiments demonstrated that the best adsorption property of As(III), Cd(II), Cu(II), and Pb(II) was achieved within 8 h with maximum adsorption capacities of 9.90, 9.73, 43.94, and 11.98 mg/g, respectively. Competitive and synergistic effects (particularly precipitation) were included in the co-adsorption mechanism of As(III) and heavy metals. Thereinto, As(III) was partly oxidized by MnFe₂O₄ to As(V), and both were coordinated on MnFe₂O₄ nanoparticles. Pb(II) could also bind to MnFe₂O₄ by ion exchange and electrostatic attraction. Furthermore, Cd(II) and Cu(II) tended to be coordinated on chitosan. Therefore, CPM can serve as a remediation material for water and soil co-contaminated with As(III) and heavy metals.     

Aerobic oxidation behavior of α-ionone catalyzed by N-hydroxyphthalimide combined with acetylacetone cobalt(II)

A practical catalytic method to oxidize α-ionone with molecular oxygen using N-hydroxyphthalimide(NHPI) combined with acetylacetone cobatt(II) (Co(acac)₂) was developed, and the probable catalytic mechanism was proposed. The influences of the reaction conditions on conversion of α-ionone and the selectivity of the major product (5-keto-α-ionone) were investigated, and the technical parameters for 5-keto-α-ionone were optimized. The results show that the primary product is 5-keto-α-ionone, and by-products include epoxy-α-ionone, as well as rearrangement products 4-keto-β-ionone and epoxy-β-ionone, which are characterized by infrared spectra, proton nuclear magnetic resonance spectra, mass spectra and elemental analysis. The selectivity of 5-keto-α-ionone and the conversion of α-ionone are 55.0% and 97.0%, respectively, when 30%(molar fraction) NHPI, 1.0%(molar fraction) Co(acac)₂ and no solvent are employed under O₂ pressure of 1.0 MPa and the reaction temperature of 65 °C for 11 h. The procedure shows good reproducibility in the parallel experiments. Foundation item: Project(50573019) supported by the National Natural Science Foundation of China     

Structural and electrochemical performance of additives-doped α-Ni(OH)2

The additives-doped α-nickel hydroxides were prepared by supersonic co-precipitation method. The crystal structure and grain size of the prepared samples were characterized by X-ray diffraction (XRD) and Particle size distribution (PSD), respectively. Cyclic voltammetry (CV) tests show that Al-Co-Y doped Ni(OH)2 has better reaction reversibility, higher proton diffusion coefficient than those of Al-Co doped Ni(OH)2. Al-Co-Y doped Ni(OH)2 also has lower charge-transfer resistance as shown by electrochemical impedance spectroscopy (EIS). Charge/discharge tests show that the discharge capacity of Al-Co-Y doped Ni(OH)2 reaches 328 mAh/g at 0.2 C and 306 mAh/g at 0.5 C, while Al-Co doped Ni(OH)2 can only discharge a capacity of 308 mAh/g at 0.2 C and 267 mAh/g at 0.5 C.