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采用气相色谱法(GC)和顶空-气相色谱/质谱法(HS-GC/MS) 测定环境水样中的二甲胺和二乙胺.优化的实验条件如下:载气为高纯氮气,流速为1 mL/min,柱温:35℃,保持15 min,以 5℃/min速度升至 80℃(GC);顶空温度80 ℃,平衡时间30 min,柱温50 ℃,离子源温度230 ℃ (HS-GC/MS).将10 mL水样移入20 mL顶空瓶中,将顶空瓶用铝盖密封.放入自动顶空进样系统中加热进行分析.在上述条件下,二甲胺(1.80~35.9 mg/L)和二乙胺(1.42~28.4 mg/L)的线性良好.GC和HS-GC/MS测定二甲胺的检出限分别为8.6和10.1 mg/L,测定二乙胺的检出限分别为0.09和0.12 mg/L; 水样平均加标回收率分别为52.6%~56 2%和86.8%~109.6%;相对标准偏差分别为2.0%,5.8%,5.5%,2.0%.结果表明,在分析挥发性的胺类物质时HS-GC/MS比GC具有较强优势.它可省略蒸馏浓缩预处理步骤,直接进样,是一种测定环境水中二甲胺和二乙胺的有效分析方法. 相似文献
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By means of the first-principles calculations, we have investigated the structural stability and electronic properties of carbon star lattice monolayer and nanoribbons. The phase stability of the carbon star lattice is verified through phononmode analysis and room temperature molecular dynamics simulations. The carbon star lattice is found to be metallic due to the large states across the Fermi-level contributed by pz orbital. Furthermore, the nanoribbons are also found to be metallic and no spin polarization occurs, except for the narrowest nanoribbon with one C12 ring, which has a ferromagnetic ground state. Our results show that carbon star lattice monolayer and nanoribbons have rich electronic properties with great potential in future electronic nanodevices. 相似文献
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