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One of the most important challenges for soil science is to determine the limits for the sustainable functioning of contaminated ecosystems. The response of soil microbiomes to kerosene pollution is still poorly understood. Here, we model the impact of kerosene leakage on the composition of the topsoil microbiome in pot and field experiments with different loads of added kerosene (loads up to 100 g/kg; retention time up to 360 days). At four time points we measured kerosene concentration and sequenced variable regions of 16S ribosomal RNA in the microbial communities. Mainly alkaline Dystric Arenosols with low content of available phosphorus and soil organic matter had an increased fraction of Actinobacteriota, Firmicutes, Nitrospirota, Planctomycetota, and, to a lesser extent, Acidobacteriota and Verrucomicobacteriota. In contrast, in highly acidic Fibric Histosols, rich in soil organic matter and available phosphorus, the fraction of Acidobacteriota was higher, while the fraction of Actinobacteriota was lower. Albic Luvisols occupied an intermediate position in terms of both physicochemical properties and microbiome composition. The microbiomes of different soils show similar response to equal kerosene loads. In highly contaminated soils, the proportion of anaerobic bacteria-metabolizing hydrocarbons increased, whereas the proportion of aerobic bacteria decreased. During the field experiment, the soil microbiome recovered much faster than in the pot experiments, possibly due to migration of microorganisms from the polluted area. The microbial community of Fibric Histosols recovered in 6 months after kerosene had been loaded, while microbiomes of Dystric Arenosols and Albic Luvisols did not restore even after a year.

In this work, simple, rapid and highly sensitive method of hazardous chemical 1,1-dimethylhydrazine (unsymmetrical dimethylhydrazine, UDMH) determination based on pre-column derivatization with unsubstituted aromatic aldehydes and reversed-phase high performance liquid chromatography-ultraviolet-tandem mass spectrometry (RP HPLC-UV-MS/MS) has been developed. Along with benzaldehyde, commercially available aromatic aldehydes, namely: 2-naphthaldehyde, 2-pyridinecarboxaldehyde, and 2-quinolinecarboxaldehyde, were used as derivatizing reagents in the analysis of hydrazines for the first time. The reactions were studied in a wide pH range by varying reaction time and other conditions. A slightly alkaline pH 9 was shown to be optimal for the derivatization of UDMH by aromatic aldehydes. The quantitative yield of derivatization products under the established conditions was confirmed by HPLC analysis with amperometric detection. For all studied reagents, wide linear ranges of concentrations (0.01-1000 μg/L) in natural water samples were observed. The limits of detection for UDMH in natural water were in the 3.7-130 ng/L range. 2-Quinolinecarboxaldehyde was selected as the most appropriate reagent for HPLC-UV-MS/MS determination of UDMH. In case of using this reagent, the accuracy was in the range of 97-102%, and precision, expressed as RSD was less than 8%. The developed approach does not require laborious stages of pre-concentration and isolation of UDMH from natural water components., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Evaluation of the chromatographic properties of covalently bonded hyperbranched stationary phase based on poly(styrene-divinylbenzene) (PS-DVB) and containing zwitterionic fragments in the structure of functional layer was conducted in suppressed ion chromatography (IC), reversed phase high performance liquid chromatography (RP HPLC), and hydrophilic interaction liquid chromatography (HILIC) modes. Besides the possibility of resolving 20 inorganic anions and organic acids using KOH eluent in suppressed IC, prepared resin provided the separation of alkylbenzenes in RP HPLC, water-soluble vitamins, amino acids, and sugars in HILIC mode. Trends in the retention of hydrophobic and polar analytes on the prepared stationary phase indicated the dominating effect of analyte nature on the retention mechanism and proved satisfactory hydrophilization of PS-DVB surface with hyperbranched functional layer for retaining polar compounds. The obtained results revealed good prospects of using hydrophobic PS-DVB substrate for preparing stationary phases for mixed-mode chromatography., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

In this paper, we assessed snow pollution by nitrogen-containing substances including rocket propellants - UDMH (unsymmetrical dimethylhydrazine, (СН 3 ) 2 NNH 2 ) and NT (nitrogen tetroxide, N 2 O 4 ) - and their transformation products (NDMA (nitrosodimethylamine, (CH 3 ) 2 NNO), NO 3 - , NO 2 - and NH 4 + ) within the falling regions (FRs) of the first and second stages of Proton-M rockets launched from the Baikonur Cosmodrome. At the first stage FR in Central Kazakhstan, snow with a pH range from 1.7 to 9.0 was contaminated by N-containing substances (maximal value in g/L): UDMH - 0.27, NDMA - 0.04, NO 3 - - 19, NH 4 + - 0.04 and NO 2 - - 0.13. The first stage landing resulted in snow contamination by soil dust particles and N-containing substances at a rate of 13 g/m 2 and 82 mg/m 2 /day, respectively. The maximal permissible addition (MPA) for UDMH, NDMA and NO 3 - to the 0-5 cm layer of soil was estimated at 0.06, 0.006 and 70.2 mg/m 2 , respectively. At the second stage FR in the NE Altai, substances released by space transportation were absent and the concentration of NO 3 - and NH 4 + corresponded to the natural background level. The index of contamination (IC) was used for characterizing the degree of snow contamination by N-containing substances. A simulation model was developed for analysing the dependence of snow contamination by rocket propellant components on the weather parameters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The chromatographic properties of three hyperbranched anion exchangers having various diamines in the external part of the functional layer are studied in order to reveal diamine influence on selectivity toward mono- and divalent organic acids. The obtained stationary phases have the same structure of the internal part of the functional layer formed by repeating 4 modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE) and amination with methylamine (MA) and differ by the structure of diamine used in the 5 th modification cycle. For the first time several diamines (ethylenediamine, (2-aminoethyl)aminoethanol, and N,N'-bis(2-hydroxyethyl)ethylenediamine) are used for completing the last modification cycle in hyperbranching. The performance of three prepared anion exchangers is investigated using KOH and NaHCO 3 as eluents and discussed with respect to the differences in hydrophilicity of the external part of the functional layer showing its effect on the separation of organic acids., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Four covalently-bonded hyperbranched anion exchangers based on poly(styrene-divinylbenzene) (PS-DVB) substrate with different structure of the functional layer were prepared using mono- and dianionic amino acids such as glycine, β-alanine, aspartic acid, and glutamic acid in the internal part of the functional layer. Selectivity of all anion exchangers toward weakly retained organic acids was investigated at different temperatures in order to evaluate the effect of the number of carboxylic groups in the functional layer and its hydrophilicity on the separation. It was found that dianionic amino acids used in the first modification cycle of hyperbranching provide the best resolution for mono- and divalent organic acids, which makes the number of carboxylic groups in the structure of amino acid a key factor in the separation of such analytes with covalently-bonded hyperbranched anion exchangers, while the role of amino acid hydrophilicity is not that significant. Stationary phases prepared using aspartic and glutamic acids provided baseline resolution for quinic, glycolic, acetic, lactic, formic, and galacturonic acids, which are not resolved to baseline with modern commercially available anion exchangers; the increase of temperature was found to be favorable for improving the resolution even further., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Three covalently-bonded poly(styrene-divinylbenzene)-based (PS-DVB) hyperbranched anion exchangers prepared using primary amines with carboxylic, sulfonic or 2-hydroxyethyl substituents in the internal part of the functional layer were studied and compared for evaluating the effect of amines substituents on the chromatographic performance of the stationary phases. The hyperbranched coating was created on the surface of aminated PS-DVB substrate by repeating the modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE) and amination with primary amine; glycine, taurine (2-aminoethanesulfonic acid) or ethanolamine were used in the first cycle, and 4 more cycles were conducted with methylamine (MA). The influence of the structure and type of primary amine used in the first cycle on the retention and selectivity toward inorganic anions, short-chain carboxylic acids, and polyphosphates was investigated using hydroxide eluent. The effect of temperature on the separation of organic acids was also studied for all stationary phases, which revealed the possibility to control and improve resolution for some pairs of analytes., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Chromatographic analysis of orange and apple juices is provided using novel covalently-bonded poly(styrene-divinylbenzene)-based (PS-DVB) hyperbranched anion exchanger for suppressed ion chromatography (IC) with improved selectivity toward inorganic anions and organic acids. The obtained stationary phase provides baseline resolution of weakly retained organic acids such as glycolate, acetate, lactate, and formate, which are not separated to baseline with modern commercially available anion exchangers. The proposed method is validated with respect to linearity, recovery, limits of detection, and intra-day and inter-day precision., (Copyright © 2018 Elsevier B.V. All rights reserved.)

For the first time novel pellicular anion-exchangers with functional layers of quaternized branched polyethyleneimine (PEI) covalently bonded to the surface of aminated poly(styrene-divinylbenzene) (PS-DVB) with 1,4-butanediol diglycidyl ether (1,4-BDDGE) as a linker are obtained and studied. The proposed method of synthesis includes alkylation of PS-DVB substrate containing secondary aminogroups with 1,4-BDDGE followed by amination with branched PEI containing primary, secondary, and tertiary amino groups. Quaternization of amino groups of PEI required for increasing ion-exchange capacity of the stationary phase is provided with two epoxides - glycidol and 1,4-BDDGE, which results in the considerable variations of ion-exchange selectivity. Chromatographic properties of the obtained anion-exchangers are evaluated using various model mixtures of anions (F - , HCOO - , CH 3 COO - , C 2 H 5 COO - , Cl - , BrO 3 - , NO 2 - , Br - , NO 3 - , ClO 3 - , S 2 O 3 2- , C 2 O 4 2- , CrO 4 2- , SO 4 2- , PO 4 3- , I - , SCN - ) in hydroxide and carbonate/bicarbonte eluents. All anion-exchangers show better selectivity toward the anions of weakly retained organic acids (acetate, formate, propionate) as compared with previously reported chemically derivatized anion-exchangers with monomeric functional sites in the ion-exchange layer. In terms of separation abilities, novel anion-exchangers with covalently-bonded PEI are not inferior to some commercial columns with grafted polymeric anion-exchange layer. Anion-exchanger quaternized with more hydrophilic glycidol packed in 10-cm long column enables the separation of 16 anions including weakly retained and highly retained polarizable ones within 26 min using gradient elution. Column efficiencies for both anion-exchangers with quaternized PEI are up to 32000 N/m and 37000 N/m in case of hydroxide and carbonate eluent, respectively, which is comparable with the values demonstrated by commercially available columns of related chemistry., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Novel pellicular poly(styrene-divinylbenzene)-based (PS-DVB) anion exchangers with covalently-bonded hyperbranched functional ion-exchange layers containing negatively charged functionalities are obtained and examined. The hyperbranched coating is created on the surface of aminated PS-DVB substrate by repeating the modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE), and amination of the terminal epoxide rings with methylamine (MA) or glycine (Gly). The influence of the position and the number of the layers with glycine, as well as of the total number of the layers of amine in the coating on the chromatographic properties of the obtained stationary phases is investigated. Chromatographic performance of the obtained stationary phases is evaluated using the model mixtures of inorganic and organic anions with hydroxide eluent. It is shown that the best selectivity toward weakly retained organic acids and oxyhalides is possessed by the anion exchanger obtained after 5 modification cycles, with glycine being used in the first one. Such anion exchanger packed in 25-cm long column is capable of separating 22 anions in 58min including 7 standard anions, mono-, di- and trivalent organic acids, oxyhalides, and some other double- and triple-charged anions., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A number of covalently-bonded hyperbranched poly(styrene-divinylbenzene)-based (PS-DVB) anion exchangers having functional ion exchange layers of different branching degrees are prepared and investigated. The attachment of the hyperbranched functional layers to the substrate surface is realized via anchor secondary amino groups inserted into the polymeric backbone by means of acylation with acetic anhydride followed by reductive amination with methylamine. Further modification of the obtained secondary amino groups is provided by repeating the steps of alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE) and amination of the terminal epoxide rings with methylamine (MA). The variation of the number of cycles including modification with 1,4-BDDGE and MA results in selectivity alterations for the obtained anion exchangers. Chromatographic parameters of the obtained stationary phases are evaluated using the model mixtures of anions (F - , HCOO - , Cl - , EtCOO - , BrO 3 - , NO 2 - , Br - , NO 3 - , SO 4 2- , PO 4 3- ) with hydroxide and carbonate/bicarbonate eluents. The anion exchangers show the increase of NO 2 - /EtCOO - and NO 2 - /BrO 3 - selectivity and the decrease of EtCOO - /Cl - selectivity with increasing the number of modification cycles. In case of anion exchanger obtained after three modification cycles, the calculated values of column efficiencies for polarizable NO 2 - and Br - are up to 18,000 and 16,000N/m, respectively., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In the last decade the developments in the field of ion chromatography (IC) were aimed at increasing the efficiency, sensitivity and rapidity of analysis, as well as on improving separation selectivity. Since selectivity and efficiency to the large extent depend on the surface chemistry of the stationary phase, the development of novel anion exchangers remains one of the priority tasks in modern IC. The exact chemistry of commercially available resins is not known and not many literature data devoted to the procedures of preparing anion exchangers for IC have become available in the last 10-15 years. However, the knowledge about the surface chemistry of anion exchangers can provide understanding of the trends in selectivity and efficiency changes, as well as help with the choice of the stationary phase type suitable for solving a particular analytical task. The current review is devoted to the methods of preparing anion exchangers based on polystyrene-divinylbenzene (PS-DVB) and ethylvinylbenzene-divinylbenzene (EVB-DVB) for IC of inorganic and small organic anions and is aimed at demonstrating the improvement of their performance over the years, which was brought by the development of the new types of stationary phase architecture., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F(-), HCOO(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3(-) and Br(-) are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE-containing analogues., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Novel poly(styrene-divinylbenzene) (PS-DVB) based anion exchangers having one and two (2,3-dihydroxypropyl) substitutes in the quaternary ammonium functional groups are prepared and characterised by ion chromatography (IC). The introduction of bulky and hydrophilic substitutes to the anion-exchange groups allows the elimination of non-ionic interactions between the polarisable anions and the aromatic rings from the matrix and the improvement of separation selectivity as compared with the traditional trimethylammonium (TMA) functionalised ion exchangers. The synthesis of the ion exchangers includes acylation of PS-DVB particles with acetic anhydride followed by reductive amination either with methylamine hydrochloride or dimethylamine and further alkylation with oxiranes under varied conditions. The ion exchange selectivity and separation efficiency of nine adsorbents having different structure of bonded groups, ion exchange capacity (9-98μequiv.g(-1)) or particle size is studied for model mixture of inorganic anions (F(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) using carbonate and hydroxide eluents. The adsorbents with more hydrophilic substitutes provided superior columns efficiencies and better peak symmetry as compared with analogues having hydrophobic functional groups. The calculated values of column efficiencies for polarisable NO3(-) and HPO4(2-) are 18,500 and 29,000N/m, respectively, for anion-exchanger, having N-methyl-N',N″-di-(2,3-dihydroxypropyl)ammonium groups which is significantly higher than 1800 and 12,000N/m obtained for these anions with anion exchanger bearing TMA functional groups., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Today the determination of hydrazines is an important application in analytical chemistry. This review shows the current state-of-the-art analyses and discusses the merits of the direct chromatographic methods for the determination of hydrazines such as ion-, ion-exclusion, ion-pair and hydrophilic interaction chromatography. The methodological aspects of the separation and detection of hydrazines are considered for these methods. Examples of hydrazine determination in real samples are presented., (Copyright © 2012 Elsevier B.V. All rights reserved.)