Porous monolithic materials for extraction and preconcentration of pollutants from environmental waters

This review presents the strengths and weaknesses of monolithic materials for the enrichment of inorganic and organic contaminants in environmental waters. We describe the most common materials (silica, organic, and hybrid organic silica) and strategies for constructing monoliths in different moulds and shapes (tubes, cartridges, stir bars, fibers) published since 2015. The functionalization of the pore surfaces enhances their affinity towards different classes of pollutants. For instance, the incorporation of chelating groups enables the enrichment of potentially toxic metals and semi-metals in aquatic environments before the analyses by spectrometric techniques. Monolithic materials for extracting emerging pollutants, diverse classes of herbicides, and fungicides were proposed recently. Incorporation of carbon-based and magnetic nanoparticles, metal-organic frameworks, and ionic liquids enhanced their adsorption capacity by either increasing the surface area or providing multiple retention mechanisms. Monoliths with molecular recognition properties for highly selective extractions have been synthesized, including boronic functionalities and molecularly imprinted cavities. The final part describes the hybrid organic silica monoliths, emphasizing metal ions and speciation analysis hyphenated with ICP-MS. In the outlook section, we point to some fields we believe monoliths will benefit, such as their 3-D technologies preparation. We also pointed their potential applicability in portable chromatographic systems, restricted access materials, and enhanced use to preconcentrate viruses from aquatic environments.     

An Allochroic Molecular Cage Switch for Sensing and Capturing Organic Pollutants

The adsorption method is considered to be one of the most promising organic pollutants emission reduction strategies. The design and synthesis of high-performance porous adsorbents are one of the most important but challenging works. In this work, we constructed a new class of porous molecular cage switches by a simple reaction using phenolphthalein as the raw material. The molecular cage switches displayed interesting on-off behavior towards organic guests, which is highly responding to organic pollutants with rapid color change and is also able to adsorb these organic pollutants through an open-to-close pathway. This molecular cage switch also has excellent regenerative cycling properties and water resistance, which is expected to be employed in the handling of organic pollutants in the future.     

Sampling and analytical framework for routine environmental monitoring of organic pollutants

Dubious data would lead to incorrect interpretations and consequently faulty conclusions. Environmental monitoring results therefore have to be unambiguous to avoid misunderstanding the problems under investigation. Representative sampling and appropriate laboratory procedures are keys to acquiring quality data in order to draw unbiased conclusions.Although a large number of studies on organic pollutants have been published, few efforts have been directed towards instituting a systematic framework from sampling design to instrumental analysis. Generally, the main components in such a framework should include sampling design, sample preparation, sample extraction, extract purification and fractionation, and quantification (including qualitative and quantitative analyses).This review outlines the sampling and analytical framework appropriate for routine monitoring of organic pollutants, particularly persistent organic pollutants widely occurring in the environment. We emphasize statistically-based sampling schemes and quality-assurance and quality-control measures desirable for environmental monitoring programs.By way of demonstrating their importance, we especially review procedures for collecting unconventional environmental samples (e.g., human blood, breast milk, human hair, fish and bird tissues, and ice and snow) and analytical methods for typical emerging organic chemicals.     

Identification strategy for unknown pollutants using high-resolution mass spectrometry: Androgen-disrupting compounds identified through effect-directed analysis

Effect-directed analysis has been applied to a river sediment sample of concern to identify the compounds responsible for the observed effects in an in vitro (anti-)androgenicity assay. For identification after non-target analysis performed on a high-resolution LTQ-Orbitrap, we developed a de novo identification strategy including physico-chemical parameters derived from the effect-directed analysis approach. With this identification strategy, we were able to handle the immense amount of data produced by non-target accurate mass analysis. The effect-directed analysis approach, together with the identification strategy, led to the successful identification of eight androgen-disrupting compounds belonging to very diverse compound classes: an oxygenated polyaromatic hydrocarbon, organophosphates, musks, and steroids. This is one of the first studies in the field of environmental analysis dealing with the difficult task of handling the large amount of data produced from non-target analysis. The combination of bioassay activity assessment, accurate mass measurement, and the identification and confirmation strategy is a promising approach for future identification of environmental key toxicants that are not included as priority pollutants in monitoring programs.     

Comprehensive two-dimensional gas chromatography in the screening of persistent organohalogenated pollutants in environmental samples

Separations of eight persistent organohalogenated classes of pollutants, organochlorinated pesticides (OCPs), polychlorinated biphenyls (PCBs), polychlorinated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated naphthalenes (PCNs), polychlorinated terphenyls (PCTs) and toxaphene (CTT) by comprehensive two-dimensional gas chromatography (GC x GC) were evaluated. Columns with different polarity and selectivity, including ZB-5, HT-8, DB-17 and BP-10, were selected as first dimension and combined with columns of increasing polarity in the second dimension, i.e. HT-8, BPX-50 and Carbowax (or Supelcowax-10). In total nine column combinations were tested. Because the main interest of the study was fast screening of the test xenobiotic families in complex matrices, in all cases, attention was primarily focussed on group-type separation. Nevertheless, within-group separation was also considered, especially for those classes containing particularly toxic congeners, such as PCBs and PCDD/Fs. Although none of the assayed column sets allowed the simultaneous and complete separation of all pollutants classes, some column combinations provided satisfactory separations among selected families and the rest of pollutants investigated. That was, for instance, the case of HT-8 x BPX-50 for PBDEs and PCDD/Fs, DB-17 x HT-8 for PCNs and OCPs and BP-10 x BPX-50 for CTT, PCDD/Fs and PBDEs. The feasibility of the proposed approach for the fast screening of the target classes of pollutants in complex samples was illustrated by the analysis of food and marine fat samples prepared using simplified miniaturised sample treatment methods.     

Halogenated methyl-phenyl ethers (anisoles) in the environment: Determination of vapor pressures, aqueous solubilities, Henry's law constants, and gas/water- (Kgw), n-octanol/water- (Kow) and gas/n-octanol (Kgo) partition coefficients

Halogenated methyl-phenyl ethers (methoxybenzenes, anisoles) are ubiquitous organics in the environment although they are not produced in industrial quantities. Modelling the fate of organic pollutants such as halogenated anisoles requires a knowledge of the fundamental physico-chemical properties of these compounds. The isomer-specific separation and detection of 60 of the 134 possible congeners allowing an environmental fingerprinting are reported in this study. The vapor pressure p0(L) of more than 60 and further physico-chemical properties of 26 available congeners are given. Vapor pressures p0(L), water solubilities S(L)W, and n-octanol/water partition coefficients Kow were determined by capillary HR-GC (High Resolution Gas Chromatography) on a non-polar phase and by RP-HPLC (Reversed Phase High Performance Liquid Chromatography) on a C18 phase with chlorobenzenes as reference standards. From these experimental data the Henry's law constants H, and the gas/water Kgw and gas/n-octanol Kgo partition coefficients were calculated. We found that vapor pressures, water solubilities, and n-octanol/water partition coefficients of the halogenated anisoles are close to those of the chlorobenzenes. A similar environmental fate of both groups can, therefore, be predicted.     

Analysing the output from primary screening

From a perspective of process knowledge and enhancement, the analysis of the results of biological screening should not be limited to the outcome of specific projects, but additionally encompass a process centric view. Summarising outcomes across multiple projects is a powerful tool to gain a greater understanding of biological screening that will also enable optimisation of the strategy for specific projects or target classes. We have analysed a set of 73,651 compounds with reproducible (confirmed) results from 63 high-throughput screening (HTS) campaigns to reveal the underlying trends in the population of active compounds. We have focused on the overall physico-chemical profile of compound populations derived from biological screening since the in vivo activity of drug molecules is the result of physico-chemical and structural properties of the compound.     

Ion chromatography-electrospray mass spectrometry for the identification of low-molecular-weight organic acids during the 2,4-dichlorophenol degradation

End-product identification of organic pollutants during oxidation water treatments is of environmental concern due to their potential toxicity. In this work the coupling of ion chromatography (IC), equipped with a membrane ion suppressor, and electrospray ionization mass spectrometry (ESI-MS) has been successfully exploited for the identification of novel low molecular weight organic acids formed as final by-products of 2,4-dichloro-phenol (DCP) degradation by Fenton's reagent, an oxidation method widely employed to degrade recalcitrant organic pollutants in industrial wastewater. The IC-ESI-MS analytical set-up not only allowed the detection of known organic acids but also the identification of 13 new low molecular weight organic acids as a result of extensive oxidation of the parent organic pollutant. Some of the novel organic acids were shown to be chlorine containing by-products and, consequently, of environmental concern. The analytical set-up could be used for characterizing the unknown organic carbon fraction arising from oxidation water treatments.     

Study of applicability of various solid-phase extraction materials for sample handling in screening analysis of organic micropollutants in water.

At present, solid-phase extraction (SPE) has become an often preferred preconcentration technique in the screening for a wide range of organic micropollutants in water. A wide choice of materials available on the market makes SPE a suitable tool to cope with an increasing variability of organic compounds entering the hydrosphere. However, the interactions of various sorbent materials with compounds having different physico-chemical properties leads inevitably to large differences in preconcentration efficiency. The aim of this paper was to investigate the efficiency of preconcentration of selected organic compounds from aqueous solutions on various SPE materials. Simultaneously, the potential of newly emerging SPE procedures was compared to results of traditional liquid-liquid extraction methods. The group of 19 tested analytes was selected so as to represent different classes of organic compounds which may occur in waters. The results obtained showed that most of the tested materials were suitable for sufficient preconcentration of a substantial part of the tested analytes. However, specific differences in recovery of one or more analytes were found for almost each sorbent even in the case when the materials had similar composition. This behaviour clearly indicates the need for a thorough testing of capabilities of any SPE material intended for the use in a wide range screening method for the identification of unknown organic micropollutants in water.     

Pesticide residue analysis (1999-2000): a review

The literature of pesticide residue analysis is reviewed selectively for the period 1999-2000. Analyses of a wide range of pesticide classes and sample types, as well as some related organic pollutants, are covered. Studies of exposure and monitoring as well as pesticide degradation, persistance, leaching, mobility, and metabolism studies are included.     

New stationary phases for normal-phase high-performance liquid chromatography (NP-HPLC)

3-(2,3-Dihydroxy-propoxy)-propyl-silica (diolsilica) was modified to bonded stationary phases for normal-phase high-performance liquid chromatography (NPLC) carrying phosphorous ester, boronic ester, and nitric acid ester groups. The NPLC phases were investigated with respect to their properties towards separations of polyaromatic hydrocarbons, and chlorinated and nitrated environmental pollutants. Aminopropyl-silica and nitrooxy-propyl-silica (the latter synthesized in our working group) are presented for comparison. Depending on the functionality used for the modification the retention behavior can significantly be changed towards the three analyte classes. Especially 2,2,2-tribromoethyl-phosphoromorpholino-chloridate modified diol-silica, 2,2,2-tribromoethyl-dichlorophosphate modified diol-silica and nitrated diol-silica (nitrooxy-propoxypropyl-silica) show specific properties for the separation of polyaromatic hydrocarbons, chlorinated analytes and nitrated analytes. Preparation and packing of the adsorbents are described. Principal Component Analysis (PCA) is used as a chemometric tool for effective data reduction and visualization of the results in terms of retention behavior of the stationary phases. Received: 4 August 1997 / Revised: 3 December 1997 / Accepted: 7 December 1997     

Introduction of organic/hydro-organic matrices in inductively coupled plasma optical emission spectrometry and mass spectrometry: A tutorial review. Part I. Theoretical considerations

Due to their outstanding analytical performances, inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are widely used for multi-elemental measurements and also for isotopic characterization in the case of ICP-MS. While most studies are carried out in aqueous matrices, applications involving organic/hydro-organic matrices become increasingly widespread. This kind of matrices is introduced in ICP based instruments when classical “matrix removal” approaches such as acid digestion or extraction procedures cannot be implemented. Due to the physico-chemical properties of organic/hydro-organic matrices and their associated effects on instrumentation and analytical performances, their introduction into ICP sources is particularly challenging and has become a full topic. In this framework, numerous theoretical and phenomenological studies of these effects have been performed in the past, mainly by ICP-OES, while recent literature is more focused on applications and associated instrumental developments. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP-OES and ICP-MS. The present Part I, provides theoretical considerations in connection with the physico-chemical properties of organic/hydro-organic matrices, in order to better understand the induced phenomena. This focal point is divided in four chapters highlighting: (i) the impact of organic/hydro-organic matrices from aerosol generation to atomization/excitation/ionization processes; (ii) the production of carbon molecular constituents and their spatial distribution in the plasma with respect to analytes repartition; (iii) the subsequent modifications of plasma fundamental properties; and (iv) the resulting spectroscopic and non spectroscopic interferences. This first part of this tutorial review is addressed either to beginners or to more experienced scientists who are interested in the analysis of organic/hydro-organic matrices by ICP sources and would like to consider the theoretical background of effects induced by such matrices.     

Surface Modification of Graphene Oxides by Plasma Techniques and Their Application for Environmental Pollution Cleanup

Graphene oxides (GOs) have come under intense multidisciplinary study because of their unique physicochemical properties and possible applications. The large amount of oxygen‐containing functional groups on GOs leads to a high sorption capacity for the removal of various kinds of organic and inorganic pollutants from aqueous solutions in environmental pollution cleanup. However, the lack of selectivity results in difficulty in the selective removal of target pollutants from aqueous solutions in the presence of other coexisting pollutants. Herein, the surface grafting of GOs with special oxygen‐containing functional groups using low‐temperature plasma techniques and the application of the surface‐modified GOs for the efficient removal of organic and inorganic pollutants in environmental pollution are reviewed. This paper gives an account of our research on the application of GO‐based nanomaterials in environmental pollution cleanup, including: (1) the synthesis and surface grafting of functional groups on GOs, summarizing various types of low‐temperature plasma techniques for the synthesis of graphene/GOs; and (2) the application of graphene/GOs and their composites for the efficient removal of organic and inorganic pollutants from aqueous solutions, including the interaction mechanism according to recently published results.     

基于蒽衍生高迁移率发光材料的研究进展

高迁移率发光有机半导体材料是实现有机发光场效应晶体管(OLETs)的重要材料, 但其设计合成面临巨大挑战. 本文综合评述了近年来高迁移率发光材料, 特别是基于蒽的高迁移率发光材料的研究进展, 重点介绍了目前报道的20余种基于蒽的高迁移率发光有机半导体材料, 包括分子的设计策略、 相关的光电性能及其在OLETs器件方面的应用研究, 以便为进一步的相关研究提供有意义的指导和借鉴. 本文还对该领域未来发展的挑战、 发展方向及机遇进行了简单评述.