高效液相色谱法测定蔬菜和粮食中的烯虫酯

建立了一种测定烯虫酯的反相高效液相色谱紫外法.样品中的烯虫酯用石油醚提取,C18ODS柱净化,以82. 5%甲醇为流动相洗脱,Phenomenex CIB(150 mm×4. 6 mmi. d,5μm)柱分离,用紫外检测器(λem=260nm)测定.研究表明,烯虫酯含量在0. 10～50. 0μg/mL范围内,峰面积与待测物的质量浓度呈良好的线性关系,相关系数为0. 998,测量结果的相对标准偏差小于4. 36%(n=5),回收率为83. 5%～102. 2%.     

Surface-plasmon-polaritons-assisted nanolithography with dual-wavelength illumination for high exposure depth

We propose a new direct writing nanolithography approach using a plasmonic focusing device and a nano silver mirror with dual-wavelength illumination for high exposure depth. Arrays of pyramid aperture are used to focus the incident light beams into 80 nm light spots. The pyramid combined with a thin silver film coated on the substrate constructs a surface plasmon polaritons (SPP) coupling cavity, which amplifies the intensity of the light field in it by SPP effect and resonance. The transmission depth of the standing wave formed by forward and reflected light could reach hundreds of nanometers. Two lasers with different wavelengths are used as illumination sources to homogenize the light field through complementation between the two standing waves. Simulation results show by using 355 nm and 441 nm wavelengths, a space of 44 nm at the bottom of the photoresist could be obtained after exposure and development. The feature size of resist patterns could be further scaled down, depending on the optimization of parameters of photoresist exposure and development, illumination wavelengths, etc.