Overview of nanosorbents used in solid phase extraction techniques for the monitoring of emerging organic contaminants in water and wastewater samples

In this article, we have critically overviewed some interesting articles published in 2015–2019 about the use of the nanosorbents for the extraction of emerging organic contaminants (EOCs) from various environmental samples. Properties, advantages, disadvantages, and the applicability of different categories of nanosorbents used for the extraction of EOCs are evaluated and discussed. The potential applications of these nanomaterials as adsorptive phase in solid-phase extraction (SPE) based techniques are reviewed.     

Rapid determination of actinides and Sr in river water

Nuclear accidents occurred in latest years highlighted the difficulty to achieve, in a short time, the quantification of alpha and beta emitters. Indeed, most of the existing methods, though displaying excellent performances, can be very long, taking up to several weeks for some radioisotopes, such as ⁹⁰Sr.     

Further investigation of a peptide extraction method with mesoporous silica using high‐performance liquid chromatography coupled with tandem mass spectrometry

Mobil Composition of Matter No. 41 (MCM‐41) was the most frequently used mesoporous silica material to extract peptides from complex biological samples. However, there were confusing extraction conditions and large extraction efficiency variance among related reports, which resulted from unclear understanding about the interaction between the material and peptides. In this study, the extraction mechanism was investigated with one set of tryptic peptides by using high‐performance liquid chromatography coupled with triple quadrupole mass spectrometry. Generally, hydrophobic interaction and electrostatic attraction were two major driving forces for extraction of peptides, while electrostatic repulsion greatly weakened the interaction between the material and peptides with isoelectric points below the pH. With most peptides positively charged and MCM‐41 slightly negatively charged, most efficient extraction was obtained at pH 3, and it was proved that electrostatic and hydrophobic interaction acted in synergy for extraction of all the peptides. A mixed solution of acetonitrile with buffers of high pH or ion strength was demonstrated to be favorable for elution, which performed much better than the commonly used eluate (mixture of acetonitrile with 0.1% trifluoroacetic acid). Finally, under optimum conditions, it was found that extraction efficiency of MCM‐41 for protein digest and human serum was greatly improved.     

稀土萃取分离技术方法研究

稀土在工业诸多领域中发挥着关键作用,在增材制造材料和介电材料等高新技术领域均显示出可期的应用前景。稀土元素的分离是衔接稀土资源与高性能稀土功能材料的关键过程,所以高效提纯稀土元素变得尤为重要。本文梳理了化学沉淀法、离子交换与吸附法、萃取色层法、溶剂萃取法、液膜分离法这些经典方法和化学气相传输法、氧化还原法、萃取沉淀法、微生物法、非平衡溶剂萃取法这些新技术方法的优缺点和适用性,侧重分析了这些技术方法在节能减排方面的最新研究情况,并展望了稀土分离提纯领域的重点发展方向,以期为稀土资源的绿色高效开发利用提供依据和借鉴。     

架构于双树轮廓波方向及相位特征的纹理图像分割

考虑到纹理的方向及相位特性,提出一种基于双树轮廓波变换的纹理图像分割新方法.双树轮廓波由塔型双树方向滤波器组构建,它不仅保持了轮廓波灵活的方向选择性,克服了传统轮廓波不具有移不变性的缺点,而且提供了复子带系数.本文以各方向子带的能量作为方向特征,复系数的平均相角作为相位特征,生成特征向量,利用模糊C均值聚类算法进行纹理图像分割.实验结果表明,相位特征是方向特征的有效补充,与传统方法相比,该方法在分割错误率、边缘准确性以及区域一致性等方面均有明显的改善.     

Selective extraction of palladium(II) using hydrazone ligand: A novel fluorescent sensor

The acyclic tridentate blue luminescent ligand (λ_ex=300 nm, λ_em=415 nm) quinoline-2-carboxaldehyde 2-pyridylhydrazone, HL, 1, was recognized as a new fluorescent chemosensor for Pd²⁺. In alkaline methanol complete fluorescent quenching was observed in the presence of 2 equivalents of Pd²⁺ that was further reflected in the solid phase fluorescence microscopic study.Ligand formed 1:1 complexes with Ni²⁺, Cu²⁺, Zn²⁺, Pd²⁺ and 1:2 complexes with Co²⁺, Fe²⁺ as obtained from Job's plot of continuous variation. The binding constants of different metal complexes (Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Pd²⁺) were estimated by fluorescence titrations. The ligand can selectively extract significant amount of Pd²⁺ from the aqueous mixture of metal ions, and the extraction efficiency was increased from 80% to 95% with increase in the molar ratio of HL, 1, to Pd²⁺ from 1 to 3. No significant interference was observed up to 2-fold excess addition of Cu²⁺ and Zn²⁺ and 100-fold excess addition of Co²⁺, Fe²⁺ and Ni²⁺over the Pd²⁺ ion concentration (1.0×10⁻³ M).     

Syntheses of two diamine substituted 1,3-distal calix[4]arene-based magnetite nanoparticles for extraction of dichromate, arsenate and uranyl ions

The synthesis of two new calixarene derivatives 4 and 5, functionalized at the lower rim with 4-amino-1-benzylpiperidine to give diamide and diamine derivatives of p-tert-butylcalix[4]arene, is described. They were obtained by the reaction of both the diester derivative of p-tert-butylcalix[4]arene (2) and the dialkyl bromide derivative of p-tert-butylcalix[4]arene (3) with 4-amino-1-benzylpiperidine. The ¹H NMR spectra of calixarene derivatives show that 4 and 5 exist in the cone conformation. Moreover, these diamide and diamine derivatives of p-tert-butylcalix[4]arene (4 and 5) have been immobilized onto [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane-modified Fe₃O₄ magnetite nanoparticles to obtain calixarene-based magnetic nanoparticles M-DADBP-Calix (6) and M-DABP-Calix (7). The calix[4]arene immobilized materials were characterized by a combination of Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Thermogravimetric Analyses (TGA) and elemental analysis. Additionally, the studies regarding the removal of As(V)/Cr(VI) ions as well as U(VI) ion from aqueous solutions were also carried out by using these compounds in liquid-liquid/solid-liquid extraction experiments.     

A review of techniques for the determination of polycyclic aromatic hydrocarbons in air

We provide an extensive review of the common methodologies employed in the analysis of airborne polycyclic aromatic hydrocarbons (PAHs). The review focuses on gas-chromatography-based approaches, in the light of their universal application with excellent separation, resolution, and sensitivity.We first describe collection methods for airborne PAHs in the gas and particle phases. We then evaluate the efficiency of extraction techniques employed for separating target PAHs from sampling media, using conventional solvent-based and emerging thermal-desorption approaches.We also describe commonly employed analytical methods with respect to their applicability to PAHs in gas and particle phases, collected from diverse environmental settings. As an essential part of basic quality assurance, we examine each method with special emphasis on key parameters (e.g., limit of detection and reproducibility).Finally, we address the likely directions of methodological developments, their limitations, and the future prospects for PAH analysis.     

微波辅助萃取应用研究进展

近年来关于微波辅助萃取(MAE)与其他各种样品前处理技术的结合使用,以及与多种检测技术在线联用的研究越来越多,此外离子液体等新型绿色溶剂作为萃取剂在MAE中的应用也开始得到广泛关注.本文综述了近几年微波辅助萃取在环境、天然产物提取、食品和药物分析领域的应用情况,并对其将来的发展进行了展望.     

Pressurized liquid extraction as a green approach in food and herbal plants extraction: A review

Pressurized liquid extraction is a “green” technology for the extraction of nutraceuticals from foods and herbal plants. This review discusses the extraction principles and the optimization of the extraction parameters that improves the extraction efficiency. The use of different solvent mixtures and other extraction additives to enhance the efficiency of the extraction are discussed. Dynamic mode of extraction in Pressurized liquid extraction, and the use of combined and hyphenated sample preparation and analytical techniques are presented. This work discusses how different studies used Pressurized liquid extraction to enrich phenolic compounds, lignans, carotenoids, oils and lipids, essential oils and other nutraceuticals from foods and herbal plants.