A Superacid-catalyzed Synthesis of Fluorescent Covalent Triazine Based Framework Containing Perylene Tetraanhydride Bisimide for Sensing to O-nitrophenol with Ultrahigh Sensitivity

Abstract

A mesoporous covalent triazine framework, PCPDI, was synthesized via an aromatic nitrile trimerization reaction of N,N′-di(4-cyanphenyl)- 3,4,9,10-tetracarboxydiimide (CPDI) by CF₃SO₃H catalyzed at 40?°C and this method avoids the use of noble metal catalyzers or high temperature reaction. PCPDI exhibits high thermal stability and strong fluorescence. The PCPDI shows ultrahigh sensitivity to tracing o-nitrophenol in chloroform with K_SV constant of 1.74?×?10⁵ L mol^?1 and detection limit (LOD) of 1.72?×?10^?11?mol L^?1.     

PPh3‐Catalyzed Ring‐Expansion Reactions of Sulfamate‐Derived Cyclic Imines with Acetylenedicarboxylates

The PPh₃‐catalyzed ring‐expansion reaction of sulfamate‐derived cyclic imines with acetylenedicarboxylates has been developed. The reaction works quite efficiently under very mild conditions to afford benzo[g][1,2,3]oxathiazocine‐4,5‐dicarboxylate 2,2‐dioxide derivatives in high yields.     

UPLC-ELSD Determination of 1-Octacosanol in Raw Material and Health Products

Determination of the levels of 1-octacosanol is important in food stuff for the study of its pharmacological activities and health benefits. In this study, a novel, simple and fast internal standard method for the non-derivatization ultra-performance liquid chromatographic determination of 1-octacosanol in raw materials and health products was developed and validated based on evaporative light scattering detection. The linearity (r ² > 0.998), recovery (99.1–100.2%, RSD <2.7%), intra- and inter-day precision (RSD <3.8%), limit of detection (1.0 mg/L), limit of quantification (2.2 mg/L) of the 1-octacosanol were determined. The method was successfully applied to nine real 1-octacosanol products. The results of analyses had close agreement with the labeled claims of 1-octacosanol content in these products. Compared with the classical gas chromatography method, the developed method was simpler, faster and more environmentally friendly due to avoiding any derivatization step. This protocol represents a rapid and feasible method for quality control of 1-octacosanol products.

     

Independence polynomials of k-tree related graphs

An independent set of a graph G is a set of pairwise non-adjacent vertices. Let α(G) denote the cardinality of a maximum independent set and f_s(G) for 0≤s≤α(G) denote the number of independent sets of s vertices. The independence polynomial defined first by Gutman and Harary has been the focus of considerable research recently. Wingard bounded the coefficients f_s(T) for trees T with n vertices: for s≥2. We generalize this result to bounds for a very large class of graphs, maximal k-degenerate graphs, a class which includes all k-trees. Additionally, we characterize all instances where our bounds are achieved, and determine exactly the independence polynomials of several classes of k-tree related graphs. Our main theorems generalize several related results known before.     

Multiple Luminescence Responses towards Mechanical Stimulus and Photo-Induction: The Key Role of the Stuck Packing Mode and Tunable Intermolecular Interactions

Organic luminescence with different forms continues to be one of the most active research fields in science and technology. Herein, an ultra-simple organic molecule (TPA-B), which exhibits both mechanoluminescence (ML) and photo-induced room-temperature phosphorescence (RTP) in the crystalline state, provides an opportunity to reveal the internal mechanism of ML and the dynamic process of photo-induced RTP in the same molecule. Through the detailed investigation of photophysical properties together with crystal structures, the key role of molecular packing and intermolecular interactions was highlighted in the luminescence response by mechanical and light stimulus, affording efficient strategies to design potential smart functional materials with multiple luminescence properties.     

基于层状模型的功能梯度板中兰姆波传播研究

功能梯度板中的兰姆波的传播在实际工程中有着非常广泛的应用。采用层状模型研究了兰姆波在材料特性沿厚度方向连续变化的功能梯度板中的传播特性。通过数值计算获得了层状板中兰姆波的色散关系,并与已有结果进行了比较,获得了材料属性沿厚度方向呈指数变化和多项式变化时功能梯度板中兰姆波的波速和位移解。当材料属性连续变化时,兰姆波各阶模态的波速与位移都将发生变化。相比于兰姆波的高阶模态,低阶模态的波速变化更加明显。本文的研究可为功能梯度板的设计提供参考。     

基体辅助激光解吸电离飞行时间质谱和热裂解色谱/质谱研究聚酯型聚氨酯链结构

聚酯型聚氨酯样品用基体辅助激光裂解离子化质谱(MALDI-TOF/MS)和热裂解色谱质谱(PYGC/MS)方法进行了鉴定,PYGV/MS方法可检出PU的一些组成单元的化学结构,但PYGC/MS中大多数的峰,无法从常规的标准化合物的质谱数据库中检索到,而MALDI-MS方法,可明确测出PU试样各种单元的组合、聚合度及PU长链的序列分布,质量数范围可达2300.     

Determination of organochlorine pesticides in propolis by gas chromatography-electron capture detection using double column series solid-phase extraction

A rapid and reliable method was developed and applied for the simultaneous determination of 17 organochlorine pesticides (OCPs) in propolis. After extraction with hexane and acetone (1:1, v/v), four sorbents (florisil, silica, graphitized carbon, and tandem graphitized carbon plus florisil) were assayed for the clean-up step. The elution solvents hexane and ethyl acetate (1:1, v/v), hexane and dichloromethane (3:7, v/v), and ethyl acetate and hexane (2:8, v/v) were studied. The results showed that the combination of the tandem graphitized carbon and florisil cartridge with the elution solvent of 6mL of ethyl acetate and hexane (2:8, v/v), which was capable of eliminating matrix interference and providing colorless eluates, was the most efficient clean-up procedure for propolis extracts when testing for OCPs. The analytical technique employed was gas chromatography with electron capture detection (GC–ECD). The correlation coefficients from linear regression for the analyzed concentrations (5∼100 μg/kg) were >0.9961. The limits of detection (LODs) varied between 0.8 μg/kg for 4,4′-DDE and 11.4 μg/kg for endosulfan II, and the limits of quantitation (LOQs) ranged from 2.6 to 38.1 μg/kg. The average recoveries varied between 62.6 and 109.6%. Relative standard deviations (RSD%) ranged from 0.8 to 9.4%. Sample analysis indicated that 4,4′-DDE was detected more often in propolis than other pesticides, such as β-HCH, δ-HCH and heptachlor. Figure GC-ECD chromatogram of a standard solution with 0.1 mg/L of OCPs     

蜂王浆中磷酸腺苷的提取及超高效液相色谱分析

比较了高氯酸提取、热水提取和热硫酸镁溶液提取3种提取方式对蜂王浆中磷酸腺苷三磷酸腺苷(ATP)、二磷酸腺苷(ADP)和单磷酸腺苷(AMP)的提取效果,发现在低温(低于4 ℃)下以5%高氯酸的提取效果最佳。采用超高效液相色谱-紫外检测法分析蜂王浆中的ATP, ADP和AMP的含量。以BEH Shield RP18柱(100 mm×2.1 mm,1.7 μm)为分析柱,以50 mmol/L的磷酸二氢铵(pH 6.5)和乙腈为流动相进行梯度洗脱,3种磷酸腺苷在4 min内实现了较好的分离。以加标王浆样品作添加回收率测定,ATP, ADP和AMP的回收率分别为84.1%～94.3%,86.2%～93.7%和91.0%～104.3%,相对标准偏差均小于10%。方法已被用于一些实际样品的分析,以了解ATP, ADP和AMP在蜂王浆样品中的分布情况。     

快原子轰击和电喷雾电离质谱表征烷基苯磺酸盐

用负离子化快原子轰击（ＦＡＢ）和电喷雾电离（ＥＳＩ）质谱并结合碰撞活化解离（ＣＡＤ）质谱方法对烷基苯磺酸盐（ＡＢＳ）进行鉴定。试样在负离子电喷雾电离（ＥＳＩ）过程中不产生碎片峰,但是在ＦＡＢ过程中产生许多碎片、比较这些谱图,就可以区别碎片峰和分子离子峰。线性或支化烷基苯磺酸盐的结构与相对含量可以在离子ＥＳＩ／ＣＡＤ－ＭＳ方法中得到。负离子ＥＳＩ－ＭＳ是快速、有效和可靠的鉴定ＡＢＳ的方法。