Trace Analysis Of Pollutants Research Articles

Preparation of a Novel Resin Based Covalent Framework Material and Its Application in the Determination of Phenolic Endocrine Disruptors in Beverages by SPE-HPLC.

A new type of economical covalent organic framework material(COF), namely resin based covalent organic framework material, was prepared by combining resin and covalent organic framework material by hydrothermal synthesis, which was based on the preparation of traditional COF material(TpBD COF). The properties of the material and covalent organic framework material were compared in the way of characterization, and the possible reaction mechanism was analyzed. The solid phase extraction separation (SPE) ability of this material for four kinds of phenolic endocrine disrupting compounds (bisphenol F, bisphenol A, octylphenol and nonylphenol) in beverage samples was investigated. The results showed that the prepared COF materials had abundant internal channels, ordered structure, large specific surface area (TpBD COF: 814.6 m2/g and resin based COF: 623.9 m2/g) and good thermal stability (pyrolysis temperature was 443 °C and 437 °C, respectively). Solid phase extraction experiments demonstrated that the two COF materials as adsorbent of solid phase extraction column had ideal adsorption separation effect and good anti-interference ability, and had strong anti-interference ability. The SPE effect was superior to the traditional solid phase extraction column. The precision RSD of this method was less than 3%. This SPE method had high recovery and could be reused (carbonated beverage: 98.18–102.18% and beverage: 98.52–101.79%), In addition, the recovery of the material did not change significantly in the 50 cycles of solid phase extraction, indicating that the material had good stability and could be reused, which could meet the requirements for the detection and analysis of trace pollutants in environmental samples. The resin based COF material prepared in this study could reduce the cost of monomer uses and provide a possibility for its industrial production. At the same time, as an efficient SPE adsorbent, it also provided a new research scheme for the enrichment of trace phenolic endocrine disruptors in beverage samples.

Imprinting Technology for Effective Sorbent Fabrication: Current State-of-Art and Future Prospects.

In the last 10 years, we have witnessed an extensive development of instrumental techniques in analytical methods for determination of various molecules and ions at very low concentrations. Nevertheless, the presence of interfering components of complex samples hampered the applicability of new analytical strategies. Thus, additional sample pre-treatment steps were proposed to overcome the problem. Solid sorbents were used for clean-up samples but insufficient selectivity of commercial materials limited their utility. Here, the application of molecularly imprinted polymers (MIPs) or ion-imprinted polymers (IIPs) in the separation processes have recently attracted attention due to their many advantages, such as high selectivity, robustness, and low costs of the fabrication process. Bulk or monoliths, microspheres and core-shell materials, magnetically susceptible and stir-bar imprinted materials are applicable to different modes of solid-phase extraction to determine target analytes and ions in a very complex environment such as blood, urine, soil, or food. The capability to perform a specific separation of enantiomers is a substantial advantage in clinical analysis. The ion-imprinted sorbents gained interest in trace analysis of pollutants in environmental samples. In this review, the current synthetic approaches for the preparation of MIPs and IIPs are comprehensively discussed together with a detailed characterization of respective materials. Furthermore, the use of sorbents in environmental, food, and biomedical analyses will be emphasized to point out current limits and highlight the future prospects for further development in the field.

Unique Graphitic Carbon Nitride Nanovessels as Recyclable Adsorbent for Solid Phase Extraction of Benzoylurea Pesticides in Juices Samples

Unique graphitic carbon nitride (g-C3N4) nanovessels have been prepared and applied as solid phase extraction (SPE) adsorbent for determining benzoylurea pesticides (BUs) in different juice samples using high performance liquid chromatography (HPLC) equipped with ultraviolet detection (UVD). The g-C3N4 nanovessels were obtained on a large scale by thermally converting low-cost urea without additive assistance, which avoided a complex synthesis process, consumption of organic solvent, and limits of tailoring the reaction pressure and atmosphere. The g-C3N4 nanovessels have been characterized using transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, and elemental analysis. The conditions affecting the extraction efficiency were optimized, including adsorbent amount, extraction time, sample volume, and choice and volume of desorption solvent. Under the optimal conditions, comparable detection limits of 6 μg/L and good recoveries of 70.4–96.4 % for six BUs have been achieved. Meanwhile, g-C3N4 nanovessels showed excellent reuse potential for ten times. The results indicated that g-C3N4 nanovessels repesented a promising SPE adsorbent for the enrichment and trace analysis of pollutants.

Emerging pollutants in the environment: present and future challenges in biomonitoring, ecological risks and bioremediation

Emerging pollutants reach the environment from various anthropogenic sources and are distributed throughout environmental matrices. Although great advances have been made in the detection and analysis of trace pollutants during recent decades, due to the continued development and refinement of specific techniques, a wide array of undetected contaminants of emerging environmental concern need to be identified and quantified in various environmental components and biological tissues. These pollutants may be mobile and persistent in air, water, soil, sediments and ecological receptors even at low concentrations. Robust data on their fate and behaviour in the environment, as well as on threats to ecological and human health, are still lacking. Moreover, the ecotoxicological significance of some emerging micropollutants remains largely unknown, because satisfactory data to determine their risk often do not exist. This paper discusses the fate, behaviour, (bio)monitoring, environmental and health risks associated with emerging chemical (pharmaceuticals, endocrine disruptors, hormones, toxins, among others) and biological (bacteria, viruses) micropollutants in soils, sediments, groundwater, industrial and municipal wastewaters, aquaculture effluents, and freshwater and marine ecosystems, and highlights new horizons for their (bio)removal. Our study aims to demonstrate the imperative need to boost research and innovation for new and cost-effective treatment technologies, in line with the uptake, mode of action and consequences of each emerging contaminant. We also address the topic of innovative tools for the evaluation of the effects of toxicity on human health and for the prediction of microbial availability and degradation in the environment. Additionally, we consider the development of (bio)sensors to perform environmental monitoring in real-time mode. This needs to address multiple species, along with a more effective exploitation of specialised microbes or enzymes capable of degrading endocrine disruptors and other micropollutants. In practical terms, the outcomes of these activities will build up the knowledge base and develop solutions to fill the significant innovation gap faced worldwide.

Trace analysis of pollutants by use of honeybees, immunoassays, and chemiluminescence detection

Specific and sensitive analysis to reveal and monitor the wide variety of chemical contaminants polluting all environment compartments, feed, and food is urgently required because of the increasing attention devoted to the environment and health protection. Our research group has been involved in monitoring the presence and distribution of agrochemicals by monitoring beehives distributed throughout the area studied. Honeybees have been used both as biosensors, because the pesticides affect their viability, and as "contaminant collectors" for all environmental pollutants. We focused our research on the development of analytical procedures able to reveal and quantify pesticides in different samples but with a special attention to the complex honeybee matrix. Specific extraction and purification procedures have been developed and some are still under optimization. The analytes of interest were determined by gas or liquid chromatographic methods and by compound-specific or group-specific immunoassays in the ELISA format, the analytical performance of which was improved by introducing luminescence detection. The range of chemiluminescent immunoassays developed was extended to include the determination of completely different pollutants, for example explosives, volatile organic compounds (including benzene, toluene, ethylbenzene, xylenes), and components of plastics, for example bisphenol A. An easier and portable format, a lateral flow immunoassay (LFIA) was added to the ELISA format to increase application flexibility in these assays. Aspects of the novelty, the specific characteristics, the analytical performance, and possible future development of the different chromatographic and immunological methods are described and discussed.

Trace analysis of pollutants in water using the photothermal interferometry as HPLC detector.

A new procedure including high performance liquid chromatography in combination with photothermal interference spectroscopy as detection device (HPLC/PIS) has been proposed, optimized and its figures of merit for pesticide residue analysis are shown. The flowing sample under study is set in one arm of a Mach-Zehnder interferometer, and its refractive index is modulated by a periodically chopped continuous wave argon ion laser. As chopper, an acousto optical modulator has been introduced to switch the excitation laser beam between different lines (457 nm, 488 nm, 514 nm) simultaneously. Thus a multi component analysis can be realized either by using an HPLC-system in front of the PIS device or by a multi line Ar(+)-laser, directly. The limit of detection of the HPLC/PIS system reached 71 microg/l of the pesticide di-nitro-ortho-cresol (DNOC).

Trace Enrichment and Chemical Derivatization in Liquid Chromatography; Problems and Potential in Environmental Analysis

Abstract The importance of detection limits in the trace analysis of pollutants is well recognized. Very often selectivity is another criterion and in order to achieve this, a chromatographic separation step may be necessary. The attainable detection level will then also depend strongly on chromatographic parameters and particularly on the injection step. It has been observed in earlier work that relatively non-polar organics dissolved in a polar solvent such as water are concentrated upon injection onto commercial reversed phase material (C8, C18) into a small zone on top of the column. This concentrating effect can be adopted for trace enrichment of pollutants in aqueous samples. It permits the use of large injection volumes up to several hundred millilitres without serious band broadening. The disadvantage of such a procedure is that interferences are also concentrated and one has to trade selectivity for sensitivity. Some of this drawback can be eliminated by using column coupling and step gradient te...

Analysis of trace pollutants in the air by means of cryogenic gas chromatography

The utilization of a laboratory-constructed programmable, cryogenic gas chromatograph (KEDBOR 1OIR 1) for use in air pollution studies is presented. The instrument ( J. Chromatogr., 89 (1974) 1) is modular in design and incorporates many commercially available components as well as a few “scratch-built” parts. A temperature control range of −100 °C to +300 °C, with five programmable rates, is possible using this particular instrument. The instrument is capable of dual-column and dual-detector operation. Data have been gathered from laboratory-prepared samples as well as from samples obtained from an air pollution study in the Philadelphia area. Small amounts (ppm or less) of the gaseous hydrocarbons and the common inorganic gases (NO x, SO x, CO, CO 2, H 2S, COS) are detected and quantitated. Calibration curves for each gaseous component have been constructed and the analyzed samples compared to them for quantitative data. Data and information from the use of several different columns, sampling sites and their locations are presented. Experimental data agreed favorably with the current findings and discussions of air pollution problems.