A portable capillary electrophoretic system with contactless conductivity detection was used for fingerprint analysis of postblast explosive residues from commercial organic and improvised inorganic explosives on various surfaces (sand, concrete, metal witness plates). Simple extraction methods were developed for each of the surfaces for subsequent simultaneous capillary electrophoretic analysis of anions and cations. Dual-opposite end injection principle was used for fast (<4 min) separation of 10 common anions and cations from postblast residues using an optimized separation electrolyte composed of 20 mM MES, 20 mM l-histidine, 30 μM CTAB and 2 mM 18-crown-6. The concentrations of all ions obtained from the electropherograms were subjected to principal component analysis to classify the tested explosives on all tested surfaces, resulting in distinct cluster formations that could be used to verify (each) type of the explosive.

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A novel method based on CE with precolumn derivatization and direct UV detection for the determination of thiodiglycol (TDG), TDG sulfoxide, and TDG sulfone in water samples was developed. The lack of a UV chromophore of target analytes was overcome by derivatization with phthalic anhydride. The reactant concentrations, as well as the derivatization dependence on heating temperature and time, were carefully investigated. The baseline separation of three derivatives was achieved in less than 8 min by applying a simple BGE composed of a 30 mM borate buffer at pH 8.5. Several parameters affecting the separation efficiency (buffer pH and concentration, capillary temperature, and applied voltage) were evaluated. Calibration curves of all compounds showed good linear correlations (R(2) > 0.9994). The LODs of the TDG and its oxidation products were in the range of 98-154 ng/mL. The precision tests resulted in RSDs for migration times and peak areas of less than 1.2 and 3.6%, respectively. The developed method was successfully applied for the analysis of TDG and oxidation products in seawater, utilizing the carbon aerogel-based adsorbents for sample purification and concentration. Additionally, the method has the potential to be transformed into a portable CE format.

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Perfluoroalkyl substances are chemical pollutants whose levels in the environment should be monitored. This work implemented nonaqueous capillary electrophoresis with conductivity detection to achieve separation of perfluoroheptanoic acid, perfluorooctanoic acid, and perfluorooctanesulfonate within 5 min. The mixture of 3‐(N‐morpholino)propanesulfonic acid and triethylamine in acetonitrile/methanol (50:50, v/v) was used as a background electrolyte. The method was linear (coefficients of determination ˃ 0.996) at analyte concentrations ranging from 2 to 20 μM with instrument detection limits varying between 0.30 and 0.75 μM depending on the analyte. The developed method was precise, the relative standard deviation of repeatability (n = 6) and reproducibility (n = 5) were less than 5.8% for the analytes used. The method was applied to the analysis of perfluoroheptanoic acid, perfluorooctanoic acid, and perfluorooctanesulfonate in wastewater samples treated by solid‐phase extraction, which further made it possible to achieve the method detection limits of perfluoroalkyl substances as low as 0.1–0.4 nM. Additionally, the applicability of the novel carbon aerogel‐based solid‐phase extraction and magnetic solid‐phase extraction were tested for the extraction of target compounds. It would be possible to transform the developed method into a portable format for on‐site analysis.

In this study, novel, fast, and simple methods based on RP-HPLC and MEKC with DAD are developed and validated for the qualitative and quantitative determination of five cyclic sulfur mustard (HD) degradation products (1,4-thioxane, 1,3-dithiolane, 1,4-dithiane, 1,2,5-trithiepane, and 1,4,5-oxadithiepane) in water samples. The HPLC method employs a C18 column and an isocratic water-ACN (55:45, v/v) mobile phase. This method enables separation of all five cyclic compounds within 8 min. With the CE method, the baseline separation of five compounds was achieved in less than 11 min by applying a simple BGE composed of a 10 mM borate buffer and 90 mM SDS (pH 9.15). Both methods showed good linear correlation (R > 0.9904). The detection limits were in the range of 0.08-0.1 μM for the HPLC method and 10-20 μM for MEKC. The precision tests resulted in RSDs for migration times and peak areas less than 0.9 and 5.5%, respectively, for the HPLC method, and less than 1.1 and 7.7% for the MEKC method, respectively. The developed methods were successfully applied to the analysis of five cyclic HD degradation products in water samples. With the HPLC method, the LODs were lowered using the SPE for sample purification and concentration.

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The European Union (EU) presented a uniform List of Waste (LoW) in 2000 and last updated the technical guidance in 2018. The respective local regulations for the classification of waste in Estonia were set in 2015. Due to the changes in the regulations, it was necessary to review the properties of solid wastes generated in Estonian oil shale industry in light of hazardous properties. Therefore, the properties of the produced ash streams were analysed and the obtained results were compared to those for coal for being in accordance with common practices. The main objective of the paper was to answer the question whether the properties of oil shale (OS) are comparable to those of coal as coal and its combustion residues were not considered hazardous waste in Europe, but the respective counterparts of oil shale were. The EU guidelines suggest the use of calculations based on trace element concentrations for the classification of hazardous property (HP) 14 -ecotoxic. Therefore, an extensive study was conducted to investigate the hazardous properties of all the solid residues from power plants operating on oil shale and shale oil production facilities. This paper describes one part of it -the trace element compositions of the major ash streams produced in the Estonian oil shale industry and focuses on their comparison with data available for coal ash samples. The findings of the study showed that, similarly to coal, oil shale ash (OSA) should not be considered as ecotoxic due to the low concentrations of trace elements. It was found that the investigated oil shale ash samples exhibited a very similar composition and properties to those of coal, and as a result of a larger study, from the beginning of 2020, oil shale ash and other oil shale thermal treatment residues are not classified as hazardous waste in Estonia, thereby initiating policy changes that affect most areas of the economy.