虚拟模板分子印迹固相萃取-高效液相色谱法检测食品中联苯三唑醇与烯唑醇

利用虚拟模板分子印迹固相萃取技术对食品中的联苯三唑醇与烯唑醇进行分离富集，并建立高效液相色谱检测方法。以腈菌唑为模板分子，丙烯酰胺（AM）为功能单体，EDMA为交联剂，乙腈为致孔剂，采用本体聚合法制备得到了腈菌唑分子印迹聚合物（MMIP），以此聚合物为固相萃取剂，制备固相萃取柱，对食品中联苯三唑醇和烯唑醇进行分离富集，并采用高效液相色谱法测定其在食品中的残留。采用C18色谱柱分离，以甲醇-水（体积比为90：10）溶液为流动相，紫外检测波长为210 nm，外标法定量。结果表明，联苯三唑醇和烯唑醇的平均回收率分别为89.40~90.88%和81.37~83.26%，RSD分别为1.08~2.04%和1.29~2.52%，检测限均为0.20 μg/g。此聚合物对两种杀菌剂具有良好的吸附能力，拟模板分子印迹固相萃取技术可以用于这两种杀菌剂的分离检测。

Hierarchical closed form solutions for plates bent by localized transverse loadings

3D and 2D closed form plate models are here applied to static analysis of simply supported square isotropic plates. 2D theories are hierarchically classified on the basis of the accuracy of the displacements and stresses obtained by comparison to the 3D exact results that could be assumed by the reader as benchmark for further analyses. Attention is mainly paid on localized loading conditions, that is, piecewise constant load. Also bi-sinusoidal and uniformly distributed loadings are taken into account. All of those configurations are considered in order to investigate the behavior of the 2D models in the case of continu- ous/uncontinuous, centric or off-centric loading conditions. The ratio between the side length a and the plate thickness h has been assumed as analysis parameter. Higher order 2D models yield accurate results for any considered load condition in the case of moderately thick plates, a/h=10. In the case of thick plates, a/h=5, and continuous/uncontinuous centric loading conditions high accuracy is also obtained. For the considered off-centric load condition and thick plates good results are provided for some output quantities. A better solution could be achieved by simply increasing the polynomial approximation order of the axiomatic 2D displacement field.