基于傅里叶变换红外光声光谱的包膜控释肥料聚合物膜疏水性的表征

以不饱和有机硅改性的丙烯酸酯为基材,在不同条件下制备了30种水基聚合物包膜控释肥料模型膜,测定了模型膜的溶胀度及模型膜的傅里叶变换红外光声光谱.分别以红外光声光谱和溶胀度为自变量和因变量进行简单相关分析,同时也构建了偏最小二乘模型,并利用该模型对模型膜的疏水性进行预测.结果表明,聚合物模型膜具有明显不同的疏水性,其红外光声光谱具有相似的吸收特征,但不同吸收带的相对强度发生明显改变;常用的简单相关分析无法实现模型膜疏水性的预测,表明模型膜的疏水性与谱区更多的特征峰相关;基于偏最小二乘法的多元校正分析具有很好的预测能力,模型的校正系数(R2)为0.9864,校正标准误差为0.70%,验证标准误差为1.92%.此模型可用于模型膜疏水性的预测.本方法样品用量少,测定快速,操作简便且可实现原位测定,为控释肥料包膜材料的研制提供新的手段.     

Performance of Pleurotus ostreatus Mushrooms and Spent Substrate for the Biosorption of Cd(II) From Aqueous Solution

The capacities of Pleurotus ostreatus mushroom and spent substrate were evaluated for the biosorption of cadmium (II) from aqueous solution in order to select the most efficient material for bioremediation. The optimum sorption conditions were optimized, including the pH of the aqueous solution, contact time, biomass dosage, initial metal concentration, and temperature. The sorption of cadmium on both biosorbents was also evaluated by several kinetic, equilibrium, and thermodynamic models. The possible heavy metal biosorption mechanisms were evaluated through point of zero charge (pH_pzc), Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX). Based on the results of column studies, the effectiveness of the P. ostreatus spent substrate was confirmed as a biosorbent for Cd(II) removal from aqueous solutions.     

HMDS/KI a simple,a cheap and efficient catalyst for the one-pot synthesis of N-functionalized pyrimidines

The syntheses of N-Alkylpyrimidine derivatives by reacting pyrimidin-2,4-diones with appropriate alkyl halide under microwave irradiation at 400?W were compared to the conventional synthesis route. These methodologies are regioselective and compatible with numerous substrates and furnish the corresponding N-alkylpyrimidines in good yields using a cheap catalyst HMDS/KI in MeCN. A comparison study between these two different modes of heating was investigated.     

Improving real-time measurement of H/D exchange using a FTIR biospectroscopic probe

We describe the improvement of a novel approach to investigating hydrogen/deuterium (H/D) exchange kinetics in biomolecules using transmission infrared spectroscopy. The method makes use of a Fourier transform infrared spectrometer coupled with a microdialysis flow cell to determine exchange rates of labile hydrogens. With this cell system, the monitoring of exchange reactions has been studied here as a function of some cell characteristics such as: (a) dialysis membrane surface contacting both the H₂O and D₂O compartments; (b) molecular cutoff of dialysis membrane; and (c) distance between the cell-filling holes. The best improvement has been obtained by increasing the dialysis membrane surface followed by increase of molecular cutoff. However, not significant differences were found using various distances between filling holes. The fastest exchange rate which can be measured with the cell system used here is found to be k = 0.41 ± 0.02 min⁻¹, that is, about threefold greater than the one got in a previous work. This microdialysis flow cell has been used here for the study of H/D exchange in nucleic acids with subsequent structural analysis by 2D correlation spectroscopy.     

苯丙胺类毒品及其衍生物的气相色谱-红外光谱分析

采用气相色谱一傅立叶变换红外光谱联用技术,建立了9种苯丙胺类毒品及其衍生物的分析鉴别方法.采用HP-1(30 m×0.32 mm,0.25 μm)毛细管柱,MCT红外检测器与氢火焰检测器同时检测,在程序升温条件下,以十七烷为内标物,研究已知对照品的色谱保留行为及其气态红外光谱图特征,建立相应的特征吸收峰数据库,作为鉴别分析的依据.色谱保留时间与红外特征吸收峰联合鉴别法极大地提高了鉴别的准确性.将发展的方法应用于可疑毒品物证中苯丙胺类及其衍生物毒品样品的鉴别,获得了理想的结果.本方法可用于涉毒案件毒品物证的检验,特别适用于混合毒品成分的检验.     

Functionalized carbon dots as sensors for gold nanoparticles in spiked samples: Formation of nanohybrids

This paper reports the synthesis, passivation and functionalization of luminescent carbon dots (CDs) possessing surface thiol ending groups. A simple procedure involving amidation of passivated carbon dots (p-CDs) with cysteamine boosts their photoluminescent properties and enables their use as easily controlled fluorescent nanosensors for determining citrate–gold nanoparticles (AuNPs). The mechanism behind the quenching phenomenon was established from fluorescence measurements at high temperatures and lifetime tests, and found to involve static quenching leading to the formation of CD–AuNP nanohybrids. A method for determining AuNPs in complex matrices was developed and validated by application to spiked drinking water and mussel tissues. The limits of detection and quantitation for AuNPs thus obtained were 0.20 and 0.66 nmol L^–1, respectively.