环境样品中微塑料分析技术研究进展

微塑料一般是指直径小于5 mm的塑料纤维、碎片或颗粒。环境中的微塑料来源广泛,性质稳定,是疏水性有机污染物和重金属的理想载体。微塑料易被浮游生物、鱼类及低等生物误食,并在食物网各营养级之间发生转移和富集,对食品安全存在潜在风险。开展微塑料分析技术研究是研究微塑料在环境中的分布、迁移、转化、归趋和生态毒理效应的基础。该文综述了国内外环境样品中微塑料的采集、分离提取、定性鉴别技术的研究进展,并探讨了各方法的优缺点。最后针对现阶段微塑料分析方法存在的问题和不足,展望了环境中微塑料分析技术的发展趋势。     

聚噻吩的固相聚合及其应用

作为共轭聚合物的典型代表,因聚噻吩衍生物具有良好的稳定性和结构易改性,其在有机光电子领域、新能源等有重要的应用。而固相聚合作为一种环保、可大规模制备等优点,受到研究者的关注。本文主要总结了近年来聚噻吩及其衍生物的固相聚合反应单体分子设计、聚合研究机理以及相关应用的进展,并展望了未来的研究方向。     

Energy‐resolved technique for discovery and identification of malonyl‐triterpene saponins in Caulophyllum robustum by UHPLC‐electrospray Fourier transform mass spectrometry

Malonyl‐triterpene saponins (MTSs) attract scientific attentions because of their structural diversities and valuable bioactivities. However, its thermal instability brings a huge amount of challenges for isolation and purification of this class of compounds. To our best knowledge, there has been no report on isolation and analysis of MTSs from genus Caulophyllum. In this study, a strategy combining data acquisition using an energy‐resolved technique and the narrow widow extracted ion chromatograms as data mining method was developed for discovery and identification of MTSs in Caulophyllum robustum hair roots by ultra high liquid chromatography coupled to electrospray ionization Fourier transform mass spectrometry. The method was performed at an independent MS full scan using our bottom‐up energies by in‐source collision induced dissociations with 0, 25, 50 and 100 eV in both positive and negative modes. Precursor ion as well as fragment ion information was simultaneously collected from four energy‐resolved MS spectra in a single run of 18 min. The fragmentation pathways of intact deprotonated, protonated and sodium ions of MTSs were proposed for the structural elucidation of Caulophyllum MTSs. A flowchart involving a stepwise procedure based on key fragments from ESI^?/ESI⁺‐FT‐MS^{(1, 1)} to MS^{(1, 4)} spectra was constructed for the identification of structural elements in the MTSs. As a result, a total of 23 MTSs were discovered and tentatively identified, which had not been reported from Caulophyllum species before. All of these were potentially new compounds. This study provides an excellent example for discovery and identification of MTSs in herb medicines. Copyright © 2016 John Wiley & Sons, Ltd.     

木质纤维素催化转化制备能源平台化合物

可再生生物质资源的能源化利用能有效缓解能源短缺和环境恶化的双重压力。木质纤维素类生物质原料通过催化转化途径可以转化成为用途广泛的平台化合物,如呋喃类化合物、多元醇和有机酸及其酯类衍生物等。以这些平台化合物为原料,通过基元反应的转化可以制备高附加值的生物质基液体燃料。基于上述背景,本文概述了国内外木质纤维素通过不同催化转化途径制备各种新能源平台化合物的研究进展。目前木质纤维素制备新能源平台化合物的可行途径主要包括液体酸催化、固体酸催化、离子液体催化和多功能材料催化。在介绍这些催化途径的同时,重点讨论了所使用的催化剂,分析了仍然存在的问题和可能的解决措施,同时对今后该领域的研究前景进行了展望。     

硫杂杯芳烃冠醚的合成及其与氨基酸配合性能的研究

在普通杯芳烃骨架中引入硫原子可以改善普通杯芳烃的配合性能。文中首先合成了硫杂杯[4]芳烃四酰肼衍生物3,在弱酸的催化下继续与化合物4反应,高产率地合成了同时含酰胺和席夫碱单元的硫杂杯[4]芳烃冠醚衍生物5,新化合物的结构经1H NMR、元素分析、ESI-MS等表征证实。同时探讨了新型硫杂杯[4]芳烃衍生物5与系列-α氨基酸的配合性能。     

菲咯啉取代苷脲的Co(Ⅱ)、Cu(Ⅱ)配合物的合成及晶体结构

以配体菲咯啉取代苷脲(L), 分别与CoCl₂·6H₂O、CuCl₂·2H₂O进行配位反应, 得到2个配合物{[Co(L)(H₂O)₃]Cl₂·2H₂O}_n(1)和[Cu₂(L)₂Cl₄]·3C₂H₅OH(2)。并用元素分析、FTIR和X-射线单晶衍射进行了表征。晶体结构表明:配合物1属于正交晶系, P2₁2₁2₁空间群, 每个Co(Ⅱ)的配位环境为扭曲的八面体, 分别与1个配体上菲咯啉单元的2个氮原子、另外1个配体的羰基氧原子和3个水分子配位, 配合物中每个配体 L 表现为三齿配体分别与2个Co(Ⅱ)离子配位桥联形成一维链状结构。配合物2属于单斜晶系, P2₁/_n空间群, Cu(Ⅱ)的配位环境为扭曲的四方锥形, 分别与配体上菲咯啉单元的2个氮原子和3个氯原子配位, 3个氯原子中有2个氯原子同时和2个Cu(Ⅱ)离子配位, 从而使配合物2形成双核配合物。     

低共熔溶剂中新型螺环吲哚衍生物的绿色合成

在低共熔溶剂氯化胆碱/草酸催化作用下,由醛、吲哚和6,10-二氧杂螺[4.5]十烷-7,9-二酮三组分多米诺Knoevenagel-Michael反应合成了一系列新型螺环吲哚衍生物,产率为70%~97%.该方法条件温和,操作简单,反应时间短,对环境友好等优点,且催化剂廉价易得.     

Chiral separation abilities of homogeneously synthesized cellulose 3,5-dimethylphenylcarbamates: Influences of degree of substitution and molecular weight

A series of cellulose 3,5-dimethylphenylcarbamates(CDMPCs) with different degrees of substitution(DS) and degrees of polymerization(DP) were homogeneously synthesized in 1-allyl-3-methylimidazolium chloride(Amim Cl). Then, the CDMPCs were coated on silica gel and used as chiral stationary phases(CSPs), and their chiral recognition abilities for seven racemates were evaluated by high performance liquid chromatography. The results showed that DS and DP of CDMPCs had a great influence on chiral recognition abilities of the CSPs. The CSPs with the DS ≈ 1 gives a low chiral recognition to most racemates. On the contrast, the CSPs with the DS ? 2 exhibited high chiral separation abilities. For example, six racemates could be separated on the CSP with CDMPC of DS ≈ 2(CSP-2). Especially, for the enantioseparation of 1-(2-naphthyl) ethanol and Tr?ger's base, CSP-2 gave the highest separation ability in all of CSPs. On the other hand, when the DP of cellulose was in a range from 39 to 220, the chiral separation abilities of CDMPCs increased as the DP increased. This work demonstrates that the structure of cellulose esters such as DS and DP has important effect on their chiral separation ability, and therefore provides a practical method to design and prepare desirable CSPs for different racemates.     

基于普鲁士蓝(PB)膜修饰铂电极的葡萄糖传感器的研究

在制备PB膜修饰铂盘电极的基础上,利用修饰电极对过氧化氢的电催化还原特性,得到了性能优良的葡萄糖传感器。作者系统地考察了有关修饰膜制备和测试实验条件对传感器性能的影响,结果表明传感器的最佳工作电位是0．05V,测试溶液的最适PH值为6．5,在选定的工作条件下,传感器的检测灵敏度为80nA/mmol.L^-1,线性范围为0．1－5mmol.L^-1,响应时间为1．5min,寿命在1个月以上,表观米氏常数为21mmol.L^-1。本方法制得的传感器能有效消除抗坏血酸,尿酸的干扰,有望用于血液中葡萄糖的直接测定。     

γ-二氧化锰/K3[Fe(CN)6]溶液界面的电子转移反转区

Marcus电子转移理论的主要成果之一是预言了电子转移反应反转区的存在.从实验上 验证Marcus反转区仍是一个热点问题.通过对γ-MnO2/K3[Fe(CN)6]溶液界面平带电位、极 化曲线的测量,计算了在极化条件下,γ-MnO2导带的电子直接转移到溶液中氧化态物种[F e(CN)6]3-空电子能级上的速率常数ket,logket对外加电位作图,观察到了Marcus反转区. 从理论上也论证了在半导体/溶液界面上的直接电子转移反转区的存在.