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991.
In this work, solid-phase microextraction coupled with gas chromatography–mass spectrometry was developed to determine trace levels of nitrobenzene compounds in water and soil samples. Graphene was chosen as the extraction material and its composite was coated on a stainless steel wire through sol–gel technique for the solid phase microextraction. The key parameters influencing the extraction efficiency were optimized. Under the optimal conditions, the linearity for the compounds was observed in the range of 0.02–15.0 mg/L for water samples, and 0.2–60.0 mg/kg for soil samples, with the correlation coefficients(r) of 0.9966–0.9987. The limits of detection of the method were 0.0025–0.005 mg/L for water samples, and 0.02–0.04 mg/kg for soil samples. The recoveries for the spiked samples were in the range of 72.0%–113.2%, and the precision, expressed as the relative standard deviations, was less than 12.1%. 相似文献
992.
Min-Jie Shi Sheng-Zhong Kou Bao-Shou Shen Jun-Wei Lang Zhi Yang Xing-Bin Yan 《中国化学快报》2014,25(6):859-864
Ionic liquid gel polymers have widely been used as the electrolytes in all-solid-state supercapacitors, but they suffer from low ionic conductivity and poor electrochemical performance. Arc discharge is a fast, low-cost and scalable method to prepare multi-layered graphene nanosheets, and as-made graphene nanosheets (denoted as ad-GNSs) with few defects, high electrical conductivity and high thermal stability should be favorable conductive additive materials. Here, a novel ionic liquid gel polymer electrolyte based on an ionic liquid (EM1MNTF2) and an copolymer (P(VDF-HFP)) was modified by the addition of ad-GNSs as an ionic conducting promoter. This modified gel electrolyte shows excellent thermal stability up to 400 ℃ and a wide electrochemical window of 3 V. An all-solid-state supercapacitor based on commercial activated carbon was fabricated using this modified ionic liquid gel polymer electrolyte, which shows obviously improved electrochemical behaviors compared with those of the corresponding all-solid-state supercapacitor using pure ionic liquid gel polymer electrolyte. Specially, smaller internal resistance, higher specific capacitance, better rate performance and cycling stability are achieved. These results indicate that the ionic liquid gel polymers modified by ad-GNSs would be promising and suitable gel electrolytes for high performance all-solid-state electrochemical devices. 相似文献
993.
994.
1,4-二酮吡咯并吡咯(DPP)由于具有优异的共平面性和强烈的拉电子能力,从而被引入D-A型窄带隙共轭聚合物中调控聚合物材料的能隙和能级结构,拓宽在可见光区域的响应范围。近年来,DPP类聚合物太阳能电池材料的研究受到广泛关注,目前基于DPP的聚合物太阳能电池效率高已达9.64%。本文探讨了以DPP作为受体单元而噻吩衍生物、芴、咔唑和苯并二噻吩等作为给体单元制成的D-A型窄带隙共轭聚合物太阳能电池的研究进展,并探讨了聚合物材料结构与太阳能电池性能之间的内在构效关系。 相似文献
995.
996.
997.
建立了亲水作用色谱快速筛查食品馅料中违法添加的二氧化硫脲的分析方法。采用0.05%醋酸溶液冰水浴超声提取二氧化硫脲,离心后经0.45μm微孔滤膜过滤后上机测试。采用亲水型色谱柱Venusil HILIC(4.6 mm×250 mm,5μm)分离,柱温为25℃,以0.02 mol/L醋酸铵(冰醋酸调至pH 4.5)和乙腈为流动相,梯度洗脱,经二极管阵列检测器分析,检测波长为275 nm。二氧化硫脲在6.0~200 mg/L范围内线性关系良好,检出限(LOD)和定量下限(LOQ)分别为22.5 mg/kg和75.0 mg/kg,方法回收率为92.7%~107%,相对标准偏差(RSD,n=6)为0.53%~3.8%。方法快速、准确、重现性好,适用于食品馅料中二氧化硫脲的快速筛查。 相似文献
998.
目的对气相色谱-质谱联用仪法测定橡胶制品中多环芳烃(蒽)含量不确定度进行评定,确定影响不确定度的关键因素。方法依据《ZEK01.4-2008 GS认证过程中PAHs的测试和验证》,使用气相色谱-质谱联用仪法测定橡胶制品中多环芳烃(蒽)含量,并对结果的不确定度进行评定,分析影响测量不确定度的各个因素,对各个分量进行计算和合成。结果扩展不确定度U=5.7 mg/kg,置信概率95%。结论该实验的不确定度主要影响因素是曲线校准。 相似文献
999.
利用靛红的羰基与β-环糊精单取代乙二胺的缩合反应,合成得到种靛红衍生化β-环糊精Schiff碱类化合物。以3-异氰酸丙基三乙氧基硅烷为偶联剂,将其键合到自制的有序介孔二氧化硅材料SBA-15表面,制得种新型的靛红衍生化β-环糊精键合SBA-15液相色谱固定相(ISCDP)。分别对β-环糊精衍生物、SBA-15及固定相进行必要的结构表征。在反相色谱条件下,以卤代尿嘧啶类极性化合物和二取代苯位置异构体为探针,评价新固定相的基本色谱性能。在极性有机溶剂和反相模式下,将新固定相分别用于β-受体阻滞剂药物和丹磺酰化氨基酸对映体的拆分,探讨了相关色谱分离机理。实验表明,靛红吲哚环的引入,增强了环糊精类固定相对卤代尿嘧啶的反相色谱分离能力,分析时间小于7 min。固定相分离硝基苯胺、氨基苯酚和苯二酚的位置异构体时也表现出较高的立体选择性,其中对位异构体均后被洗脱,这与包结作用相关;靛红衍生化β-环糊精配体也提高了固定相的手性分离能力,除疏水作用外,靛红衍生化β-环糊精配体还能提供偶极、氢键、π-π和包结等作用,多种协同作用力有利于提高新固定相的手性和非手性分离的选择性。SBA-15作为键合基质,其有序的孔结构有利于保持色谱柱的良好渗透性和小的传质阻力,在快速高效分离分析中具有应用潜能。 相似文献
1000.
Three homoleptic lanthanide complexes, [C6H5COCHC(CH3)N(p-ClC6H4)]3Ln(THF)n(n = 0, Ln = Yb(1); n = 0, Ln = Y(2); n = 1, Ln = Nd(3)), were synthesized by amine elimination reaction of Ln[N(SiMe3)2]3 with 1-phenyl-3-N-(p-chlorophenylimino)-1-butanone. These complexes crystallize in triclinic, space group P1 with a = 9.805(3), b = 14.831(6), c = 16.075(6) A, α = 111.996(9), β = 91.570(7), γ = 93.744(6)°, V = 2159.4(13) A3, Z = 2, D3 c = 1.515 g/cm, F(000) = 986, μ(MoKα) = 2.396 mm-1, R = 0.0360 and wR = 0.0850 for 9548 observed reflections with I 2σ(I) for complex 1; a = 9.861(5), b = 14.852(9), c = 16.111(9) A, α = 112.362(13), β = 91.949(11), γ = 93.678(14)°, V = 2173(2) A3, Z = 2, Dc = 1.377 g/cm3, F(000) = 924, μ(MoKα) = 1.570 mm-1, R = 0.0735 and wR = 0.1389 for 8015 observed reflections with I 2σ(I) for complex 2; and a = 9.308(3), b = 15.357(3), c = 17.419(4) A, α = 66.493(13), β = 88.61(2), γ = 86.664(19)°, V = 2279.4(9) A3, Z = 2, Dc = 1.499 g/cm3, F(000) = 1046, μ(MoKα) = 1.364 mm-1, R = 0.0843 and wR = 0.2280 for 8433 observed reflections with I 2σ(I) for complex 3. Each central metal in complexes 1 and 2 is six-coordinated by three nitrogen and three oxygen atoms from three β-ketoiminate ligands to give a distorted octahedral geometry, while the central metal in 3 is seven-coordinated by three nitrogen and three oxygen atoms from three β-ketoiminate ligands and one oxygen atom from the solvated THF molecule to complete a distorted monocapped trigonal prism. 相似文献