微波辅助提取-紫外分光光度法检测土壤中的油脂总量

以合成土样为对象 ,研究了微波辅助提取油脂的条件及其提取效率 ,由此建立了土壤中油脂分析的快速光度检测方法。在中档微波场辐射 3× 10 s时 ,2次 15 m L丙酮 -正己烷 (体积比 1∶ 1)萃取 10 g合成土样中的油脂时所获收率最高。方法的平均回收率大于 97.3% ,RSD小于 2 .5 % ,其结果与索氏萃取 4 h的效果相当     

微波辐射法合成4A沸石及表征

本文主要是采用微波辐照的方法合成4A沸石分子筛,并先后以纯化学原料,工业用高岭土为原料等进行合成,结果表明4A沸石合成的质量与微波功率及辐照时间密切相关,用高岭土为原料能合成出与化学法具有同等质量的4A沸石。     

微波消解/ICP-MS法测定中草药中痕量元素的研究

研究了微波消解 / ICP- MS测定中草药中痕量元素的新方法。方法的检出限为 0 .0 0 6—0 .0 37ng·m L-1;精密度为 0 .6 %— 4 .5% ;回收率为 88.2 %— 10 8%。该方法简单、快速、准确 ,结果令人满意。     

微波溶样-原子吸收法间接测定叶片中的叶绿素总量

以10mL 0.5mol/L盐酸为溶剂,微波溶解卟啉环中的镁离子,原子吸收法间接测定了植物叶片的叶绿素平均含量。方法的回收率为98.5%,RSD为2.46%。     

芳香基苯并咪唑衍生物的合成、表征及抑菌活性研究

在微波辐射下,通过二茂铁磺酰氯和相应的苯并咪唑合成了4种芳香基苯并咪唑衍生物。经^1H NMR、MS及元素分析确证产物结构。通过X线衍射测定了化合物4a的晶体结构。用琼脂稀释法测定化合物抑菌活性,并与对照药剂50%多菌灵可湿性粉剂比较,结果表明化合物4a～4d对番茄早疫病菌、烟草赤星病菌和小麦赤霉病菌有与对照药剂近似的抑菌活性。     

中草药中槲皮素的毛细管电泳法测定

近年来,毛细管电泳法用于中药的分析正在逐渐展开．微波辅助萃取是微波与传统的溶剂萃取法相结合后形成的一种新的萃取方法,目前已被用于环境、食品和天然产物的提取等领域,我们也曾用微波萃取法研究了中药刺五加和黄芩中的黄酮类化合物。     

微波辐射下固相反应合成二苯基甲基醚

在常压下用微波辐射固相反应的方法合成了二苯基甲基醚,与用有机溶剂为介质及传统的热固相反应方法相比,其反应速率快,产率高。     

微波辐射下的1,4-二甲基咔唑-9-羧酸的快速合成

以ＤＭＦ为溶剂,在微波辐射下由１,４－二甲基咔唑和相应的溴酯快速合成了两种１,４－二甲基咔唑－９－羧酸化合物,在最佳反应条件下,产率分别为８５．２％和８３．１％。     

Zeolite HY and Silica Gel as New and Efficient Heterogenous Catalysts for the Synthesis of Triarylimidazoles under Microwave Irradiation

Summary.  Zeolite HY and silica gel efficiently catalyzed the three component condensation of benzil, benzaldehyde derivatives, and ammonium acetate under solvent-free conditions and microwave irradiation. Received February 22, 2000. Accepted (revised) March 22, 2000     

Comparison between Total Determination and Extractable Heavy Metals from River Sediments using Conventional and Microwave Accelerated Leaching Tests

Abstract

In the present study the concentration of heavy metals (Cu, Cr, Ni, Pb and Zn) in sediments collected from different sampling stations of the Leça river (Portugal) was determined, using Flame Atomic Absorption Spectrometry. In order to estimate the potential mobility of metals in these samples, the results of the total digestion were compared with those obtained by single extractions using EDTA and acetic acid as extractant solutions; in all samples studied, Cu and Zn were found to be the most mobile elements; Ni and Pb showed a smaller mobility in presence of either acidic medium and complexing ligands; Cr was found the least mobilizable element, given that the low extractability obtained with the two extractants tested in this work. In the single extraction tests, microwave energy was also employed to replace the conventional treatment and only in the case of the EDTA the results obtained were similar to those of the conventional procedure (recoveries between 90.16 and 98.76%); the precision (RSD, n=3) of the proposed microwave procedure for EDTA extractions was comparable to those of the conventional method with values always lower than 8% for all metals.