Eco-friendly and low-cost amidoxime-functionalized microcrystalline cellulose/mesoporous silica composite for the selective adsorption of U(VI) from aqueous solution

Journal of Radioanalytical and Nuclear Chemistry - Eco-friendly and low-cost composite, amidoxime-functionalized microcrystalline cellulose/mesoporous silica (MCC/MS-AO), were synthesized by...     

师范专业认证背景下无机化学课程教学改革探索*

以北京师范大学化学专业的无机化学课程改革为例,从教学内容、教学方法、课程考核等方面探讨无机化学课程优化和改革。明确教学目标,提升教学质量,达成化学(师范)专业的毕业要求,全面提升学生的思想政治素养、专业知识技能和教育情怀。     

A Facile and Highly Efficient Approach to Obtain a Fluorescent Chromogenic Porous Organic Polymer for Lymphatic Targeting Imaging

Porous organic polymers have an open architecture, excellent stability, and tunable structural components, revealing great application potential in the field of fluorescence imaging, but this part of the research is still in its infancy. In this study, we aimed to tailor the physical and chemical characteristics of indocyanine green using sulfonic acid groups and conjugated fragments, and prepared amino-grafted porous polymers. The resulting material had excellent solvent and thermal stability, and possessed a relatively large pore structure with a size of 3.4 nm. Based on the synergistic effect of electrostatic bonding and π–π interactions, the fluorescent chromogenic agent, indocyanine green, was tightly incorporated into the pore cavity of POP solids through a one-step immersion method. Accordingly, the fluorescent chromogenic POP demonstrated excellent imaging capabilities in biological experiments. This preparation of fluorescent chromogenic porous organic polymer illustrates a promising application of POP-based solids in both fluorescence imaging and biomedicine applications.     

POLYMERIZATION OF OCTAFLUOROCYCLOBUTANE IN GLOW DISCHARGE Ⅱ. ESCA AND IR CHARACTERIZATION OF POLYMER STRUCTURE*

In a capacitively coupled discharge with external electrodes, He, H_2, N_2 or Ar were used as plasmagas, polymerization of octafluorocyclobutane was carried out under different conditions by varyingdischarge power, pressure, plasma gas and plasma-gas/monomer ratio. Structure of polymerizedproducts was characterized by IR spectroscopy and ESCA measurement. It was found that therewere six elements in the products, i.e. C, F, Si, O, N and H. The probably existed groups in poly-mers wer investigated. By analyzing the resolved peaks of C_(1S) region in ESCA spectra, effect of thereaction conditions on degree of branching of the polymerized products and the relationship of thepolymer structure wth the mechanism of the competitive ablation and polymerization process werestudied. In addition, polymer deposition process occurring in glow discharge was discussed.     

辉光放电质谱法测定高纯材料中痕量硫杂质

准确测定并控制材料中杂质元素含量是发挥高纯材料性能不可或缺的环节。辉光放电质谱法(GDMS)是准确、快速、高灵敏分析高纯材料中痕量及超痕量硫的理想方法。对GDMS分析高纯铜和镍基高温合金中痕量硫的质谱干扰进行了讨论,优化了放电电流和放电电压,采用多种标准物质对硫的相对灵敏度因子(RSF)进行了校准和验证,并与二次离子质谱法(SIMS)进行分析结果比对,验证了GDMS定量分析结果的准确性和可靠性。     

双一流背景下有机化学精准教学的探究实践*

有机化学课程是本校化学师范和高分子材料与工程2个国家级一流本科专业以及应用化学、制药工程等专业基础必修课程。由于化学师范和非师范专业的培养目标不同,有机化学的精准教学方面也有所差异。主要从理论教学、实验教学和多媒体教学等3个方面对化学师范专业和非师范专业有机化学差异化精准教学进行了探究实践,化学师范专业有机化学的精准教学侧重于培养学生的教学能力,非师范专业有机化学的精准教学侧重于培养学生的应用能力。     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱法非靶向筛查苹果中苯脲类农药

建立了超高效液相色谱－四极杆/静电场轨道阱高分辨质谱（UPLC-Q/Orbitrap HRMS）非靶向筛查苹果中苯脲类农药的方法。样品采用QuEChERS法提取净化,Acquity BEH C18色谱柱（100 mm × 2.1 mm,1.7 μm）分离,以甲醇和含0.1%甲酸的水溶液为流动相进行梯度洗脱,在电喷雾正离子模式下采用四极杆/静电场轨道阱高分辨质谱进行检测。将13种苯脲类除草剂和9种苯甲酰脲类杀虫剂按化学结构分为4类。首先通过对4类22种典型苯脲类农药标准品的准分子离子和二级质谱碎片进行分析,总结苯脲类农药的质谱裂解规律如下：绿麦隆等9种苯脲类除草剂的主要特征离子碎片为m/z 72.044 59,可通过特征丢失中性分子二甲胺（m/z 45.058 03）产生特征离子碎片;绿谷隆等4种苯脲类除草剂可通过特征丢失中性分子甲醇［CH3OH］或卤化氢［HR1］（R=Cl,Br,F）产生离子碎片;除虫脲等7种含氟苯甲酰脲杀虫剂的主要特征离子碎片为 m/z 158.040 47、141.015 00,也可发生特征中性丢失2,6-氟苯甲酰胺结构［C8H3F2O2NH2］（m/z 183.013 21）;杀铃脲等2种含氯苯甲酰脲类杀虫剂的主要特征离子碎片为m/z 156.020 25、138.993 76、113.015 28。利用该方法对北京12份市售苹果进行非靶向筛查,在1份样品中筛查出绿麦隆。该方法可为快速筛查农产品中相似结构特征的苯脲类化合物提供参考。     

多学科交叉融合工程人才培养模式探索与实践——以非织造材料与工程专业为例

多学科交叉融合工程专业人才培养是当前高等教育人才产出的重要发展方向,如何做好学科交叉工程人才培养是当前工科专业建设发展面临的重要问题.非织造材料与工程专业是为满足国家产业用纺织品人才需求而设立的工科专业,具有高分子材料、化学、机械、纺织等多学科交叉且实践性较强的特点.本文从培养方案、课程体系、师资队伍、教学方法和人才培...     

酶解样品-高效液相色谱法测定糯米类制品中10种合成着色剂的含量北大核心CSCD

取糯米类制品5 g,经中温淀粉酶(2 000~7 000 U·g^(-1)) 150 mg于60℃水浴中酶解6 h,得到酶解待测液。在上述溶液中加入调成粥状的聚酰胺粉(0.075~0.15 mm) 1 g,经G3垂溶漏斗抽滤,滤饼依次经60℃水(10 mL×3)淋洗,体积比7∶2∶1的乙醇-氨水-水混合液(15 mL×3)洗脱,所得洗脱液加热浓缩至5 mL左右,浓缩液用水定容至20 mL,离心。所得上清液采用高效液相色谱法测定其中10种合成着色剂的含量,以C_(18)色谱柱为固定相,以不同体积比的甲醇和20 mmol·L^(-1)乙酸铵溶液的混合液为流动相梯度洗脱,二极管阵列检测器在430 nm(检测柠檬黄),500 nm(检测日落黄、新红、胭脂红、苋菜红、诱惑红、偶氮玉红、赤藓红),600 nm(检测靛蓝、亮蓝)等3个波长条件下检测。结果表明:10种合成着色剂的质量浓度均在0.2~20.0 mg·L^(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)为0.19~0.43 mg·kg^(-1)。按标准加入法进行回收试验,回收率为76.9%~94.0%,测定值的相对标准偏差(n=6)均小于4.0%。方法用于分析市售的10批糯米类制品,3批样品检出合成着色剂,分别为柠檬黄、日落黄、亮蓝。本法与国家标准GB 5009.35-2016测定结果相比,有效克服该类食品的假阴性结果。     

影响β—环糊精及其衍生物对萘胺荧光增强效应的一些因素

研究一有机溶剂，无机盐，尿素对萘胺－β－环糊精及其衍生物荧光体系的影响，发现它们对萘胺有荧光增强效应，初步探讨了其中的作用机理。