Inclusion of emerging contaminants into water quality monitoring programs can serve as an additional layer for protecting water resources against deterioration. Based on prior non-target screening using LC-QTOF, a direct injection liquid chromatography-electrospray ionization-tandem mass spectrometry with multiple reaction monitoring method was developed for the determination of 23 micropollutants in natural waters. The combination of methodological simplicity, flexibility, environmental compatibility, and demonstrated performance under real-world monitoring conditions represents a significant advancement over existing chromatographic strategies for the determination of relevant and emerging pollutants. The method provides high sensitivity and reliability, enabling the simultaneous quantification of target analytes (pesticides, pharmaceuticals and products of their transformation) spanning a wide polarity range (XLogP3 0.3-6.1) and extending the applicability of multianalytes chromatographic analysis to complex environmental matrices. The limits of detection and quantification and linearity were evaluated in deionized water, groundwater, and surface water, while accuracy in terms of recovery and precision were determined in surface water. Pesticides provided satisfactory recoveries ranging from 83 to 120%, with quantification limits between 0.02 µg L-1 and 0.18 µg L-1, whereas pharmaceuticals displayed recoveries of 83-119%, with quantification limits of 0.03-0.20 µg L-1 in different types of water. Using the developed method, 599 water samples were analyzed between 2023 and 2025. The most frequently detected compounds at concentrations above the limit of quantification were terbumeton-desethyl, prometon and benzenesulfonamide in groundwater; fluconazole and sulfamethoxazole in surface water; and propazine-2‑hydroxy, terbuthylazine-2‑hydroxy and carbamazepine in both types of water samples.

Nontargeted and suspect screening with liquid chromatography-high resolution mass spectrometry (LC-HRMS) has become an indispensable tool for quality assessment in the aquatic environment – complementary to targeted analysis of organic (micro)contaminants. An LC-HRMS method is presented, suitable for the analysis of a wide variety of water related matrices: surface water, groundwater, wastewater, sediment and sludge, including extracts from passive samplers and on-site solid phase enrichment, while focusing on the data processing aspect of the method. A field study is included to demonstrate the practical application and versatility of the whole process. HRMS/MS data were recorded following LC separation in both (ESI) positive and negative ionization modes using data dependent as well as data independent acquisition. Two vendor (Agilent's Personal Compound Database and Library and from National Institute of Standards and Technology) and one open (MassBank/EU) tandem mass spectral libraries were utilized for the identification of compounds via mass spectral match. The development of a novel software tool for parsing, grouping and reduction of MS/MS features in data files converted to mascot generic format (MGF) helped to substantially decrease the amount of time and effort needed for MS library search. While applying the method, in the course of the entire field study, 18771 detections (from 870 individual compounds) in total were recorded in 275 samples, resulting in 68.3 identified compounds per sample, on average. Among the top ten most frequently detected contaminants across all samples and sample types were pharmaceutical compounds carbamazepine, 4-acetamidoantipyrine, 4-formylaminoantipyrine, tramadol, lamotrigine and phenazone and industrial contaminants toluene-2-sulfonamide, tolytriazole, tris(2-butoxyethyl) phosphate and benzotriazole. Exploratory data analysis methods and tools enabled us to discover organic pollutant occurrence patterns within the comprehensive sets of qualitative data collected from various projects between the years 2018–2023. The results may be used as valuable inputs for future water quality monitoring programs.

The possibilities of expanding a groundwater quality monitoring scheme by passive sampling using polar organic chemical integrative sampler (POCIS) comprising HLB sorbent as the receiving phase were explored. Passive sampling and grab sampling were carried out simultaneously in the regions with vulnerable groundwater resources in Slovakia, between 2013 and 2021. For 27 pesticides and degradation products detected both in POCIS and the grab samples, in situ sampling rates were calculated and statistically evaluated. The limited effectiveness of the receiving phase in POCIS for sampling polar or ionized compounds was confirmed through a comparison of the medians of compound-specific sampling rates. For the majority of the monitored compounds the median sampling rates varied between 0.01 and 0.035 L/day. In some cases, the actual in situ values could be confirmed by parallel exposure of POCIS and silicone rubber sheet employed to obtain a benchmark for maximum attainable sampling rate. Sampling site and sampling period appear to have also some influence on the sampling rates, which was attributed in part to the groundwater velocity varying in both space and time. The influence of physico-chemical parameters (temperature, pH, electrolytic conductivity) remains mostly questionable due to the naturally limited ranges of recorded values over the entire duration of the study. Concentrations of pollutants in POCIS could be used for predicting time weighed average concentrations in water, provided the sampling rates were known and relatively constant. Generally, the compound-specific sampling rate cannot be considered constant due to a combination of naturally varying environmental factors that influence the actual in situ sampling rate. The relative standard deviation of concentration data from POCIS exposed in triplicates varied between approx. 5 %-50 %. Utilizing exploratory data analysis approach and tools enabled us to obtain a relatively complex picture of the situation and progress regarding pesticide pollution of groundwater in the monitored areas.

Long-lived radicals were observed in irradiated room temperature ionic liquids (RTILs) composed of the bis (trifluoromethylsulfonyl)imide anion (Tf2N-) with 1-hexyl-3-methylimidazolium (hmim+) and1-butyl-3methylimidazolium (bmim+) cations. The EPR signal intensity increases within hours and the spectral pattern changes during the time after irradiation. The kinetics data obtained indicate the existence of at least two distinct radical cations that have different formation and decay rates. We demonstrate that oxygen does not react rapidly with the radical species formed. The bmim + Tf2N- was selectively deuterated at various positions which allowed us to suggest possible structures of the stable radicals formed. The first structure is a radical cation containing 2 nitrogens and 6 protons all with ca. 8.2 Gauss hyperfine splittings, and 2 protons with 2.8 Gauss splitting. The structure of the second radical cation is similar, but characterized by an odd number of hydrogens with ca. 8.2 Gauss splitting. Extensive quantum chemistry calculations were performed to attempt to identify the structure of these persistent radicals. The most likely candidates are imidazole radical cations having methyl groups at the nitrogen atoms and substituents in the second position of the imidazole ring.

The Watch List (WL) is a monitoring program under the European Water Framework Directive (WFD) to obtain high-quality Union-wide monitoring data on potential water pollutants for which scarce monitoring data or data of insufficient quality are available. The main purpose of the WL data collection is to determine if the substances pose a risk to the aquatic environment at EU level and subsequently to decide whether a threshold, the Environmental Quality Standards (EQS) should be set for them and, potentially to be listed as priority substance in the WFD. The first WL was established in 2015 and contained 10 individual or groups of substances while the 4th WL was launched in 2022. The results of monitoring the substances of the first WL showed that some countries had difficulties to reach an analytical Limit of Quantification (LOQ) below or equal to the Predicted No-Effect Concentrations (PNEC) or EQS. The Joint Research Centre (JRC) of the European Commission (EC) organised a series of workshops to support the EU Member States (MS) and their activities under the WFD. Sharing the knowledge among the Member States on the analytical methods is important to deliver good data quality. The outcome and the discussion engaged with the experts are described in this paper, and in addition a literature review of the most important publications on the analysis of 17-alpha-ethinylestradiol (EE2), amoxicillin, ciprofloxacin, metaflumizone, fipronil, metformin, and guanylurea from the last years is presented.

The Partnership for Chemicals Risk Assessment (PARC) is currently under development as a joint research and innovation programme to strengthen the scientific basis for chemical risk assessment in the EU. The plan is to bring chemical risk assessors and managers together with scientists to accelerate method development and the production of necessary data and knowledge, and to facilitate the transition to next-generation evidence-based risk assessment, a non-toxic environment and the European Green Deal. The NORMAN Network is an independent, well-established and competent network of more than 80 organisations in the field of emerging substances and has enormous potential to contribute to the implementation of the PARC partnership. NORMAN stands ready to provide expert advice to PARC, drawing on its long experience in the development, harmonisation and testing of advanced tools in relation to chemicals of emerging concern and in support of a European Early Warning System to unravel the risks of contaminants of emerging concern (CECs) and close the gap between research and innovation and regulatory processes. In this commentary we highlight the tools developed by NORMAN that we consider most relevant to supporting the PARC initiative: (i) joint data space and cutting-edge research tools for risk assessment of contaminants of emerging concern; (ii) collaborative European framework to improve data quality and comparability; (iii) advanced data analysis tools for a European early warning system and (iv) support to national and European chemical risk assessment thanks to harnessing, combining and sharing evidence and expertise on CECs. By combining the extensive knowledge and experience of the NORMAN network with the financial and policy-related strengths of the PARC initiative, a large step towards the goal of a non-toxic environment can be taken.

The radiolytic stability of a series of room-temperature ionic liquids (ILs) composed of bis(trifluoromethylsulfonyl)imide anion (Tf2N-) and triethylammonium, 1-butyl-1-methylpyrrolidinium, trihexyl(tetradecyl)phosphonium, 1-bexyl-3-methylpyridinium, and 1-hexyl-3-methylimidazolium (hmim) cations was studied using spin-trap electron paramagnetic resonance (EPR) spectroscopy with a spin-trap alpha-(4-pyridyl N-oxide)-N-tert-butylnitrone (POBN). The trapped radical yields were measured as a function of POBN concentration and as a function of radiation dose by double integration of the broad unresolved lines. Well-resolved motionally narrowed EPR spectra for the trapped radicals were obtained by dilution of the ILs with CH2Cl2 after irradiation. The trapped radicals were identified as mainly carbon-centered alkyl and (CF3)-C-center dot, and their ratio varies greatly across the series of ILs. Expected nitrogen-centered radicals derived from Tf2N- were not observed. The hmim liquid proved most interesting because a large part of the trapped radical yield (entirely carbon-centered) grew in over several hours after irradiation. We also discovered a complicated narrow-line stable radical signal in this neat IL with no spin trap added, which grows in over several hours after irradiation and decays over several weeks.

A “dynamic” passive sampling (DPS) device, consisting of an electrically driven large volume water pumping device coupled to a passive sampler exposure cell, was designed to enhance the sampling rate of trace organic compounds. The purpose of enhancing the sampling rate was to achieve sufficient method sensitivity, when the period available for sampling is limited to a few days. Because the uptake principle in the DPS remains the same as for conventionally-deployed passive samplers, free dissolved concentrations can be derived from the compound uptake using available passive sampler calibration parameters. This was confirmed by good agreement between aqueous concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) derived from DPS and conventional caged passive sampler. The DPS device enhanced sampling rates of compounds that are accumulated in samplers under water boundary layer control (WBL) more than five times compared with the conventionally deployed samplers. The DPS device was deployed from a ship cruising downstream the Danube River to provide temporally and spatially integrated concentrations. A DPS-deployed sampler with surface area of 400 cm2 can reach sampling rates up to 83 L d−1. The comparison of three passive samplers made of different sorbents and co-deployed in the DPS device, namely silicone rubber (SR), low density polyethylene (LDPE) and SDB-RPS Empore™ disks showed a good correlation of surface specific uptake for compounds that were sampled integratively during the entire exposure period. This provided a good basis for a cross-calibration between the samplers. The good correlation of free dissolved PAHs, PCBs and HCB concentration estimates obtained using SR and LDPE confirmed that both samplers are suitable for the identification of concentration gradients and trends in the water column. We showed that the differences in calculated aqueous concentrations between sampler types are mainly associated with different applied uptake models.

Abstract We investigated the degradation of biphenyl and identified main degradation products. Biphenyl and 2,3-dihydroxybiphenyl (2,3-DHB) was added to cultivation media to identify whole collection of degradation products of four bacterial strains isolated from long-term PCB contaminated soil (Alcaligenes xylosoxidans and Pseudomonas stutzeri) and long-term PCB contaminated sediment (Ochrobactrum anthropi and Pseudomonas veronii). Cultivation flasks were processed in different time after inoculation to determine biphenyl fission rate. Alcaligenes xylosoxidans was revealed as the most appropriate strain for bioremediation process with the highest biphenyl transformation rate. Biphenyl degradation led to the formation of benzoic acid. However, as the presence of 2-hydroxy-6-oxo-6-phenylhex-2,4-dienoic acid (HOPDA) was not confirmed, the transformation pathway common for many other bacteria is probably modified.

Yields of H2 produced by electron beam irradiation were investigated in a series of room-temperature ionic liquids comprising 1-hexyl-3-methylimidazolium, 1-hexyl-4-(dimethylamino)pyridinium, 1-butyl-1-methylpyrrolidinium, triethylammonium or trioctyl(tetradecyl)phosphonium cations associated with bis(trifluoromethylsulfonyl)imide anion. The G(H2) values ranged from 2.6×10−8mol/J for the imidazolium and pyridinium-based ionic liquids to 2.5×10−7mol/J for the phosphonium liquid. These results correlate well with yields of gaseous hydrogen in studies of nonionic aliphatic and aromatic organic compounds.

Laser flash photolysis with the Fourier transform electron paramagnetic resonance (FT EPR) and optical spectroscopy detection methods on the nanosecond time scale have been employed in order to investigate the oxidation mechanism of cyclic dipeptides glycine, alanine, and sarcosine anhydrides initiated by SO4*- or 9,10-anthraquinone-2,6-disulfonate (2,6-AQDS) triplet in oxygen free aqueous solutions. A direct hydrogen abstraction from the ring C-H position of an anhydride by both oxidants is proposed as the primary reaction, rather then an electron transfer from nitrogen followed by (alpha)C-H deprotonation. The overall second-order rate constants for the reaction with SO4*- were determined to be 7.2 x 10(7) M(-1) s(-1), 1.2 x 10(8) M(-1) s(-1), and 5.2 x 10(8) M(-1) s(-1) for glycine anhydride, alanine anhydride, and sarcosine anhydride, respectively. The rate constants for 2,6-AQDS triplet as oxidizing species are about two times lower. The radical intermediate products derived from cyclic dipeptides observed on the microsecond time scale were assigned to the general structure of piperazine-2,5-dione-3-yl radical. These are spin polarized by the mechanisms of chemically induced dynamic electron polarization (CIDEP). For SO4*- as the oxidant the spectra are exhibiting an E/A* polarization pattern originating partially from F-pairs of two piperazine-2,5-dione-3-yl radicals.

Using time-resolved Fourier transform electron paramagnetic resonance, FT EPR, and optical spectroscopy, the photooxidation of glycine, alpha-alanine, alpha-aminoisobutyric acid, and model compounds beta-alanine, methylamine and sodium acetate, by excited triplets of anthraquinone-2,6-disulfonate dianion was studied in aqueous solutions in the pH range 5-13. Anthraquinone radical trianions showing strong emissive spin-polarization (CIDEP) were formed, indicating fast electron transfer from the quenchers to the spin-polarized quinone triplet as the primary reaction. None of the primary radicals formed upon one-electron oxidation of quenchers could be detected at the nanosecond time scale of FT EPR measurements because of their very fast transformation into secondary products. The latter were identified to be decarboxylated alpha-aminoalkyl radicals for alpha-amino acids anions and zwitterions, beta-aminoalkyl radicals for beta-alanine zwitterions, and methyl radicals for acetate anions; corresponding aminyl radicals were the first EPR detectable products from beta-alanine anions and methylamine. Thus, anthraquinone-2,6-disulfonate triplet can take an electron from both NH(2)- and -CO(2)(-) functional groups forming aminium ((+*)NH(2)-) and acyloxyl (-CO(2)(*)) radicals, respectively. Aminium radicals derived from beta-alanine anions and CH(3)-NH(2) stabilize by deprotonation into aminyl radicals, whereas these derived from alpha-amino acids anions are known to suffer ultrafast decarboxylation (tau approximately 10 ps). Analysis of the polarization patterns revealed that decarboxylation from acyloxyl radicals are considerably slower (ns < tau < 0.1 micros). Therefore, in the case of alpha-amino acids, the isoelectronic structures NH(2)-CR(2)-CO(2)(*) and (+*)NH(2)-CR(2)-CO(2)(-) probably do not constitute resonance mesomeric forms of one and the same species and the decarboxylation of aminium radicals is not preceded by the intramolecular carboxylate to amino group electron transfer. Absolute triplet quenching rate constants at zero ionic strength were in the range of 2 x 10(8) to 2 x 10(9) M(-1) s(-1) for R-NH(2) and 2 x 10(7) to 10(8) M(-1) s(-1) for R-CO(2)(-) type of electron donors, reflecting in principle their standard reduction potentials. The strengths of acids: (+)NH(3)-(*)CH(2), (+)NH(3)-(*)C(CH(3))H, and (+)NH(3)-(*)C(CH(3))(2), pK(a) <4, >6, and >7, respectively, were found to be remarkably strongly dependent on alpha-C substitution. The conjugate bases of these alpha-aminoalkyl radicals reduce anthraquinone-2,6-disulfonate dianion ground state with k(sec) = 3 x 10(9) M(-1) s(-1).

Using time-resolved Fourier transform electron paramagnetic resonance (FT EPR) spectroscopy, the photooxidation of glycine methyl and ethyl esters by spin-polarized triplets of anthraquinone-2,6-disulfonate was studied in aqueous solution in the pH range 9-10. Quinone radical anions showing strong emissive spin-polarization (CIDEP) were formed, indicating fast electron transfer from the glycine esters to the spin-polarized quinone triplet as the primary reaction. The lifetime of the simultaneously formed glycine ester aminium radical cations was too short for detection by FT EPR in the nanosecond time-scale. Fast deprotonation of aminium radicals from nitrogen and alpha-carbon sites led to the generation of two successor radicals, the aminyl radical (NH)-N-.-CH2-CO2R and the glycyl radical NH2-(CH)-C-.-CO2R (R = Me or Et) in the ratio of 1:9, respectively. Glycyl radicals were found to be present in two isomeric forms (Z and E), as unambiguously identified from their FT EPR spectra. The assignment to the two isomers was supported by quantum chemical DFT calculations. The calculated hfc constants for aminyl radicals and for (E)/(Z) glycyl radicals are in accordance with experimental values. The concentration ratio of (Z) and (E) isomers was determined to be 7:3. No interconversion was observed within 1 mus at room temperature. Results are discussed in the light of their relevance to the oxidation mechanism and, in particular, to the enantioselective synthesis of aliphatic amino acids and their derivatives.

The Fourier transform electron paramagnetic resonance (FT EPR) spectroscopy has been employed as a detection technique in the investigation of the photooxidation of glycylglycine dipeptide, induced by triplet-sensitized electron transfer to 9,10-anthraquinone-2,6-disulfonate in aqueous solutions at pH 6-10. Spin-polarized (CIDEP) radical species +NH3/NH2-CH2-CONH-(CH2)-C-. and (NH)-N-.-CH2-CONH-CH2-COO- were identified as transient products formed on the nanosecond time scale. The radicals have been found to originate from two different reaction channels depending on the pH. The first channel, leading to the decarboxylated radical product. occurs in the whole pH range and is ascribed to the oxidative attack of the triplet on the peptide and/or carboxylate functional groups. At pH > 8 where the peptide terminal amino group exists in deprotonated form. the second channel, electron transfer from the amino group nitrogen nonbonding electron pair followed by deprotonation, becomes possible. This reaction leads to the formation of the observed aminyl radical.

The radical intermediates produced upon UV irradiation of deoxygenated alcoholic titanium dioxide suspensions of nitrosobenzene, nitrobenzene, 2-nitrosotoluene, 2,3,5,6-tetramethylnitrosobenzene, 3,5-di-bromo-4-nitrosobenzenesulfonate (sodium salt), 2,4,6-tri-t-butyl-nitroso-benzene, and 2-methyl-2-nitrosopropane were investigated using in situ EPR technique. Nitrosobenzene is efficiently photoreduced in TiO2 suspensions (toluene/alcohol, 1:1 (v/v)) forming exclusively one stable radical intermediate corresponding to C6H5NOH species. The formation of this radical species is consistent with the proposed photocatalytic reduction mechanism, occurring from the primary generated nitrosobenzene mono-anion by the hydrogen abstraction from surroundings. The origin of hydrogen added to the nitroso group was demonstrated by the photocatalytic experiments using deuterated methanol, where the production of C6H5NOD was established. Additionally, an identical radical C6H5NOH was detected, when nitrobenzene was reduced under analogous experimental conditions. The photoinduced electron transfer from TiO2 to nitroso compounds is accompanied by alcohol oxidation via the photogenerated titanium dioxide valance band holes forming alkoxy and hydroxyalkyl radicals. Production of hydroxyalkyl radicals (CH2OH, CH(OH)CH3, C(OH)(CH3)2) with redox potentials suitable for a direct electron transfer to nitroso compounds represents an alternative reaction pathway for their reduction. On the other hand, the investigated nitroso derivatives are efficient spin-trapping agents, therefore, formation of nitroxyl radical spin adducts was observed in the photocatalytic experiments. The EPR spectra monitored upon irradiation of substituted nitrosobenzene derivatives in alcoholic TiO2 suspensions reveal the correlation between nitrosobenzene derivative first step reduction potentials and yield of radical species produced.

Organic pollutants are often present in the water column at trace concentrations that are difficult to detect when conventional low volume spot sampling of water is applied. The scope of the sampling campaign performed using passive samplers was the screening of trace organic pollutants and their toxic potentials in the water column of the Danube, as well as the assessment of their spatial distribution along the river.