| 1. |
- Aro, Rudolf, 1992-, et al.
(author)
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Calibration and Uncertainty Estimation for Water Content Measurement in Solids
- 2021
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In: International journal of thermophysics. - : Springer. - 0195-928X .- 1572-9567. ; 42:3
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Journal article (peer-reviewed)abstract
- In the field of water content measurement, the calibration of coulometric methods (e.g., coulometric Karl Fischer titration or evolved water vapor analysis) is often overlooked. However, as coulometric water content measurement methods are used to calibrate secondary methods, their results must be obtained with the highest degree of confidence. The utility of calibrating such instruments has been recently demonstrated. Both single and multiple point calibration methods have been suggested. This work compares these calibration methods for the evolved water vapor analysis technique. Two uncertainty estimation approaches (Kragten's spreadsheet and M-CARE software tool) were compared as well, both based on the ISO GUM method.
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| 2. |
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| 3. |
- Aro, Rudolf, 1992-, et al.
(author)
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Combustion ion chromatography for extractable organofluorine analysis
- 2021
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In: iScience. - : Cell Press. - 2589-0042. ; 24:9
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Journal article (peer-reviewed)abstract
- Combustion ion chromatography (CIC) has found a role in environmental analytical chemistry for fluorine content analysis. It is used for extractable organofluorine (EOF) analysis to evaluate perfluoroalkyl and polyfluoroalkyl substances (PFASs) and other organofluorine burden. The prevailing assumption has been that all PFASs are incinerated in CIC and matrix components have no impact on this process, but this has not been experimentally evaluated. In this work, the combustion efficiencies of 13 different PFASs were determined (66-110%). A notable difference was observed between calibrating the CIC with inorganic fluorine or organofluorine. Potential interferences from cations and coextracted matrix components from whole blood and surface water samples were evaluated. These observations should be acknowledged when performing EOF analysis using CIC, overlooking either non-100% combustion efficiencies or the differences in calibrating the CIC with inorganic fluorine or organofluorine could lead to underestimating EOF content and through that to misguide policy decisions.
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| 4. |
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| 5. |
- Aro, Rudolf, 1992-, et al.
(author)
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Extractable organofluorine analysis: A way to screen for elevated per- and polyfluoroalkyl substance contamination in humans?
- 2022
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In: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 159
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Journal article (peer-reviewed)abstract
- The ubiquitous occurrence of a few per- and polyfluoroalkyl substances (PFAS) in humans and the environment has been previously reported. However, the number of PFAS humans and the environment are potentially exposed to is much higher, making it difficult to investigate every sample in detail. More importantly, recent studies have shown an increasing fraction of potentially unknown PFAS in human samples. A screening tool for identifying samples of concern that may contain high PFAS levels, to be studied more thoroughly, is needed. This study presents a simplified workflow to detect elevated PFAS levels using extractable organofluorine (EOF) analysis. A fluorine mass balance analysis on samples with high EOF, targeting 63 PFAS, can then confirm the PFAS contamination. Whole blood samples from a cohort of individuals with historical drinking water contamination from firefighting foams (n = 20) in Ronneby (Sweden) and a control group (n = 9) with background exposure were used as a case study. The average EOF concentration in the Ronneby group was 234 ng/ mL F (<107-592 ng/mL F) vs 24.8 ng/mL F (17.6-37.8 ng/mL F) in the control group. The large difference (statistically significant, p < 0.05) in the EOF levels between the exposed and control groups would have made it possible to identify samples with high PFAS exposure only using EOF data. This was confirmed by target analysis, which found an average n-ary sumation PFAS concentration of 346 ng/mL in the exposed group and 7.9 ng/mL in the control group. The limit of quantification for EOF analysis (up to 107 ng/mL F using 0.5 mL whole blood) did not allow for the detection of PFAS levels in low or sub parts per billion (ng/mL) concentrations, but the results indicate that EOF analysis is a suitable screening method sensitive enough to detect elevated/significant/exposure above background levels by known or unknown PFAS.
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| 6. |
- Aro, Rudolf, 1992-, et al.
(author)
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Fluorine Mass Balance Analysis of Effluent and Sludge from Nordic Countries
- 2021
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In: ACS - ES & T Water. - : American Chemical Society (ACS). - 2690-0637. ; 1:9, s. 2087-2096
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Journal article (peer-reviewed)abstract
- Recent publications have highlighted the ubiquitous presence of unidentified organofluorine compounds, whose environmental occurrence is poorly understood. In this study, wastewater treatment plant (WWTP) effluent and sludge samples from seven countries were analyzed for extractable organofluorine (EOF) and target PFAS, to evaluate which compounds are released back into the environment. Fluorine mass balance analysis of effluent samples (n = 14) revealed that on average 90% of the EOF could not be explained by the 73 PFAS monitored in this investigation. The levels of EOF in effluent (324–1460 ng of F/L) and sludge (39–210 ng of F/g of dry weight) indicate that a substantial amount of organofluorine compounds is released back into nature. A commonly overlooked PFAS class, ultra-short-chain PFCAs, accounted for 4% of EOF on average, while the remaining 71 compounds explained only a further 6% of EOF on average. The highest number of PFAS was detected in the effluent dissolved phase (37), compared to 29 and 23 PFAS in sludge and effluent particulate phase, respectively. The increased concentrations of EOF in both WWTP effluent and sludge are of concern, as the chemical species contained therein remain largely unknown, and thus, their potential health and environmental risks cannot be assessed.
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| 7. |
- Aro, Rudolf, 1992-, et al.
(author)
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Fluorine mass balance analysis of selected environmental samples from Norway
- 2021
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In: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 283
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Journal article (peer-reviewed)abstract
- The presence of unidentified organofluorine compounds (UOF) has been investigated in recent publication, but their environmental occurrence is still poorly understood. Fluorine mass balance analysis was performed on environmental samples from lake Mjøsa and river Alna (surface water (n = 9), sediment (n = 5) and fish liver (n = 4)) and sewage samples from Oslo (n = 5), to reveal to the fraction of UOF. In samples that had extractable organofluorine (EOF) concentrations above the limit of detection (LoD), more than 70% of their EOF could not be accounted for by the 37 PFAS monitored in this study. The surface water samples from lake Mjøsa had EOF concentrations several times higher than what has been reported elsewhere in Nordic nations. The flux of EOF in river Alna and selected sewage pipes revealed that it was 1-2 orders of magnitude higher than the flux of the measured PFAS. The elevated concentrations of EOF in all samples pose a potential health and environmental hazard, as their composition remains mostly unknown.
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| 8. |
- Aro, Rudolf, 1992-, et al.
(author)
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Moisture in Solids : Comparison Between Evolved Water Vapor and Vaporization Coulometric Karl Fischer Methods
- 2020
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In: International journal of thermophysics. - : Springer. - 0195-928X .- 1572-9567. ; 41:8
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Journal article (peer-reviewed)abstract
- Moisture content can affect the thermo-physical properties of many materials. Thus sufficient knowledge of this parameter is required to improve product shelf life and quality, reduce waste or enhance process efficiency. The traditional loss on drying methods are still the go-to methods due to their robustness and simplicity. However, their inherent lack of selectivity imposes restrictions. These are overcome with newer techniques such as vaporization coulometric Karl Fischer titration (vap-C-KFT) and evolved water vapor analysis (EWV). The former is a well-established method, but the latter was more recently introduced and the literature available on it is scarce. This work aims to bridge this gap in knowledge and demonstrate the comparability of the EWV to the more established vap-C-KFT. Multiple samples were studied and the data are analyzed along the principles reported recently by INRiM with a few modifications.
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| 9. |
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| 10. |
- Aro, Rudolf, 1992-, et al.
(author)
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Organofluorine Mass Balance Analysis of Whole Blood Samples in Relation to Gender and Age
- 2021
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:19, s. 13142-13151
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Journal article (peer-reviewed)abstract
- Studies have highlighted the increasing fraction of unidentified organofluorine (UOF) compounds in human blood, whose health effects are not known. In this study, 130 whole blood samples from the Swedish general population were analyzed for extractable organofluorine (EOF) and selected per- and polyfluoroalkyl substances (PFAS). Organofluorine mass balance analysis revealed that 60% (0-99%) of the EOF in female samples could not be explained by the 63 monitored PFAS; in males, 41% (0-93%) of the EOF was of unidentified origin. Significant differences between both age groups and gender were seen, with the highest fraction of UOF in young females (70% UOF, aged 18-44), which is contrary to what has been reported in the literature for commonly monitored compounds (e.g., perfluorooctane sulfonic acid, PFOS). Increasing the number of monitored PFAS did not lead to a large decrease of the UOF fraction; the seven highest PFAS (C8-C11 PFCAs, C6-C8 PFSAs) accounted for 98% of sum 63 PFAS. The high fraction of UOF in human samples is of concern, as the chemical species of these organofluorine compounds remain unknown and thus their potential health risks cannot be assessed.
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| 11. |
- Aro, Rudolf, 1992-
(author)
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Organofluorine Mass Balance and Per- and Polyfluoroalkyl Substance Analysis of Environmental Samples and Human Blood
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- Per- and polyfluoroalkyl substances (PFAS) have been linked to a range of negative health and environmental effects. Regulations limiting and/or banning the use of some of the legacy compounds have been introduced. Consequently, the production and use of PFAS has diversified. The risks posed by these newly introduced PFAS to both the environment and humans may be underestimated if they are not evaluated in current monitoring programs. Organofluorine mass balance analysis has been used in previous studies to estimate the overall exposure to PFAS since naturally occurring organofluorine compounds are rare in nature.In this thesis, the organofluorine mass balance analysis was performed on a variety of samples, from surface water to sewage and human blood. The results indicated the ubiquitous presence of unidentified organofluorines in all environmental compartments and human samples, for example, more than 50 % of extractable organofluorine (EOF) in human samples could not be accounted for by an extended list of target analytes. Until these compounds are identified, it is not possible to assess the risks they pose and it could lead to misguided policy decisions.To tackle the increasingly complex analytical picture and ensure more comprehensive screening, a workflow using EOF as an initial metric to identify pollution hot-spots was proposed. The wider adoption of organofluorine mass balance analysis would also require a better understanding of the analytical instrumentation used for this type of work. Experiments carried out here demonstrated the robustness of combustion ion chromatography in EOF analysis and highlighted areas in need of improvement.While organofluorine mass balance analysis has its drawbacks, the potential health and environmental risks posed by the unidentified organofluorine compounds cannot be underestimated.
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| 12. |
- Ayoub, M. W. Ben, et al.
(author)
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Quantification of free and bound water in selected materials using dielectric and thermo-coulometric measurement methods
- 2018
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In: Journal of physics communications. - : Institute of Physics Publishing (IOPP). - 2399-6528. ; 2:3
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Journal article (peer-reviewed)abstract
- Broadband electromagnetic characterization offers useful tools for the quantitative estimation of water content in a insulating solid materials. However, the correlation between electromagnetic characteristics and the amount of water in solids needs to be characterized using precise direct measurement methods. In this study, a two-port coaxial transmission cell has been characterized for water content estimation based on a study with the thermo-coulometric water detection method. The latter allows us to determine the proportions of the different water bonding forms that can exist in the material. The purpose of this paper is to provide a dielectric relaxation behavior study of the kaolinite clay from 10 MHz to 1.5 GHz, which was preceded by an experimental analysis of alpha-D-lactose monohydrate and the calcium oxalate monohydrate, which have stable water content under various humidity conditions.
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| 13. |
- Ayoub, M. W. Ben, et al.
(author)
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Quantitative determination of bound water in cardboard by measurement of dielectric permittivity
- 2018
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In: Measurement science and technology. - : Institute of Physics Publishing (IOPP). - 0957-0233 .- 1361-6501. ; 29:2
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Journal article (peer-reviewed)abstract
- In this study we investigated the complex dielectric permittivity of cardboard with different water contents using a coaxial transmission/reflection technique from 10 MHz to 1.5 GHz. A relaxation process was analyzed to identify the bonding forms that exist in cardboard; this analysis was accompanied by a selective direct thermo-coulometric method. Two different types of bonding of water are found in cardboard (free and bound water) and both can be eliminated at 105 degrees C. The novelty of this work is the experimental correlation between the relaxation frequency situated in the radio-frequency band and the fraction of bound water in cardboard with a low water content.
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| 14. |
- Bell, S., et al.
(author)
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METefnet : Developments in metrology for moisture in materials
- 2015
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In: 17th International Congress of Metrology, CIM 2015. - Les Ulis, France : EDP Sciences.
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Conference paper (peer-reviewed)abstract
- Bien que les mesures de teneur en eau soient largement utilisées dans l'industrie, les considérations métrologiques quant à cette mesure ne sont pas complètement abouties de sorte à fournir des mesures fiables et traçables au SI. Afin de remédier à ceci, le projet de recherche conjoint, Joint Research Project SIB64 “METefnet – Metrology for moisture in materials”, est actuellement en cours, et contribue au programme européen de recherche en métrologie European Metrology Research Programme. Le projet METefnet a pour objectifs de développer et d'améliorer l'approche métrologique de ce sujet. Ceci inclus notamment: le travail sur de nouvelles méthodes de référence pour évaluer la fraction massique en eau, l'amélioration des mesures mettant en œuvre la méthode primaire de type titration Karl Fischer, le développement de nouveaux matériaux de référence certifiés présentant une très bonne stabilité et permettant une traçabilité au SI, le développement de nouveaux étalons de transfert, la réalisation d'études visant à quantifier et réduire les effets liés à la prise d'échantillon, son transport et sa manipulation, le développement d'une nouvelle méthode pour étalonner les instruments mesurant l'humidité de surface, et l'amélioration des méthodes d'estimation d'incertitudes de ces mesures. Ce travail, réalisé dans le domaine de la métrologie de l'humidité au sein des matériaux, couvre à la fois le mesurande décrit comme étant spécifiquement la teneur en eau, seule, dans les matériaux, mais également un mesurande plus large pouvant inclure l'eau ainsi que d'autres liquides ou composés organiques volatiles; ceci afin de bien mettre en exergue la différence qui peut être observée entre ces deux mesurandes. Le projet global a pour objectif de soutenir une action de dissémination et de traçabilité au système SI des mesures de teneur en eau dans les matériaux avec une exactitude optimale et de développer une infrastructure métrologique cohérente pour ce type de mesures. Le travail technique ainsi que les dernières avancées vous sont ainsi présentées.
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| 15. |
- Haiba, E., et al.
(author)
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Degradation of diclofenac and triclosan residues in sewage sludge compost
- 2017
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In: Agronomy Research. - : Eesti Pollumajandusulikool. - 1406-894X. ; 15:2, s. 395-405
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Journal article (peer-reviewed)abstract
- Land application of sewage sludge compost is an important and efficient tool in the remediation of industrial landscapes and agricultural soils in Estonia. A number of studies have shown that, as a rule, pharmaceuticals and personal care products (PPCPs) are neither completely removed by sewage treatment, nor completely degraded in the environment. In this study, degradation rates of diclofenac sodium (DFC) and triclosan (TCS) were determined during sewage sludge composting. Anaerobically digested and dewatered sewage sludge was mixed with sawdust at two different ratios (1:2 and 1:3 sludge/sawdust, v:v). Then aerobic composting was carried out. These ratios were chosen on the basis of previous studies on sewage sludge composting with different bulking agents. The initial concentration of DFC and TCS was 2 mg kg-1 in relation to dry weight (dw). Low quantities of the studied pharmaceuticals were present in sewage sludge that was used for preparing the compost mixtures used in our experiments. The background concentrations of DFC and TCS were never equal to zero. The results showed that the difference between sewage sludge and bulking agent ratios (1:2 vs 1:3) in compost samples did not significantly affect temperature profiles during the experiment. The degradation of pharmaceuticals was more complete in the compost samples where the ratio of bulking agent was higher (1:3 by volume). The average degradation level (in all compost mixtures) was 95% for DFC and 68% for TCS. Pharmaceuticals entering into the soil may affect microbial activity, plant growth and development, and may have adverse effects on living organisms.
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| 16. |
- Hecht, Max, et al.
(author)
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Sponge Spray-Reaching New Dimensions of Direct Sampling and Analysis by MS
- 2017
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 89:21, s. 11592-11597
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Journal article (peer-reviewed)abstract
- Sample preparation for the analysis of clinical samples with the mass spectrometer (MS) can be extensive and expensive. Simplifying and speeding up the process would be very beneficial. This paper reports sponge spray-a novel sampling and direct MS analysis approach-attempting exactly that. It enables direct analysis without any sample preparation from dried blood, plasma, and urine. The tip of a volumetric absorptive microsampling device is used to collect an exact amount of sample and from that same tip an electrospray can be directed into a mass spectrometer. We demonstrate here that, although with significant matrix effects, quantitation of penicillin G, a common antimicrobial, is, possible in plasma and in urine, with essentially no sample preparation.
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| 17. |
- Kaiser, Andreas-Marius, et al.
(author)
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Comparison of extraction methods for per- and polyfluoroalkyl substances (PFAS) in human serum and placenta samples-insights into extractable organic fluorine (EOF)
- 2021
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In: Analytical and Bioanalytical Chemistry. - : Springer. - 1618-2642 .- 1618-2650. ; 413, s. 865-876
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Journal article (peer-reviewed)abstract
- Since the detection of per- and polyfluoroalkyl substances (PFAS) in humans and different environmental media in the last two decades, this substance group has attracted a lot of attention as well as increasing concerns. The fluorine mass balance approach, by comparing the levels of targeted PFAS after conversion to fluorine equivalents with those of extractable organic fluorine (EOF), showed the presence of unidentified organofluorine in different environmental samples. Out of the thousands of PFAS in existence, only a very small fraction is included in routine analysis. In recent years, liquid chromatography coupled with tandem-mass spectrometry (LC-MS/MS) has demonstrated the ability to analytically cover a wide spectrum of PFAS. In contrast, conventional extraction methods developed 10 to 15 years ago were only evaluated for a limited number of PFAS. The aim of the present study was to evaluate the advantages and disadvantages of three different extraction methods, adapted from the literatures without further optimization (ion-pair liquid-liquid extraction, solid-phase extraction (SPE), using hydrophilic-lipophilic (HLB) or weak anion exchange (WAX) sorbents), for human biomonitoring of 61 PFAS in serum and placental tissue samples. In addition, levels of EOF were compared among these extraction methods via spiked samples. Results showed that performance, in terms of recovery, differed between the extraction methods for different PFAS; different extraction methods resulted in different EOF concentrations indicating that the choice of extraction method is important for target PFAS and EOF analysis. Results of maternal serum samples, analyzed in two different laboratories using two different extraction methods, showed an accordance of 107.6% (± 21.3); the detected perfluoroalkyl acids (PFAAs) in maternal and cord serum samples were in the range of 0.076 to 2.9 ng/mL.Graphical abstract.
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| 18. |
- Kaiser, Andreas-Marius, et al.
(author)
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Extractable Organofluorine Analysis in Pooled Human Serum and Placental Tissue Samples from an Austrian Subpopulation : A Mass Balance Analysis Approach
- 2021
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:13, s. 9033-9042
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Journal article (peer-reviewed)abstract
- Embryos and fetuses are of major concern due to their high vulnerability. Previous studies demonstrated that human exposure to per- and polyfluoroalkyl substances (PFAS) may be underestimated because only a limited number of known PFAS can be measured. This investigation studied the total PFAS exposure by measuring the extractable organofluorine (EOF) in pooled maternal serum, placental tissue, and cord serum samples (total number of pooled samples: n = 45). The EOF was analyzed using combustion ion chromatography, and the concentrations of known PFAS were determined using ultraperformance liquid chromatography coupled with a tandem mass spectrometer. Using a mass balance analysis approach, the amount of unknown PFAS was estimated between the levels of known PFAS and EOF. The EOF levels ranged from 2.85 to 7.17 ng F/mL (21 PFAS were quantified) in the maternal serum, from 1.02 to 1.85 ng F/g (23 PFAS were quantified) in the placental tissue, and from 1.2 to 2.10 ng F/mL (18 PFAS were quantified) in the cord serum. An average of 24, 51, and 9% of EOF is unidentified in the maternal serum, placental tissue, and cord serum, respectively. The results show that the levels of unidentified EOF are higher in the placental tissue, suggesting accumulation or potential transformation of precursors in the placenta.
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| 19. |
- Koch, Alina, 1990-, et al.
(author)
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Towards a comprehensive analytical workflow for the chemical characterisation of organofluorine in consumer products and environmental samples
- 2020
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In: TrAC. Trends in analytical chemistry. - : Elsevier. - 0165-9936 .- 1879-3142. ; 123
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Research review (peer-reviewed)abstract
- This review summarizes and discusses eight analytical methods for organofluorine (OF) analysis, which offer detection limits suitable for consumer products and environmental samples. Direct sample analysis of OF only applies to some techniques on consumer products, whereas others require sample pretreatment or concentration before measurements. Comparison between methods for OF analysis were found to be difficult because of different selectivity (between OF and fluoride), sensitivity and type of samples (bulk, extract, surface) analysed. Neither inter-laboratory comparison on OF analysis nor suitable certified reference materials have been used for method validation, which makes data comparability between studies challenging. A top down approach for the comprehensive assessment of OF is proposed, where OF/extractable OF is first measured, followed by target analysis to obtain unquantifiable OF concentrations using the mass balance approach. For further identification of unquantifiable OF, approaches such as total oxidizable precursor assay, suspect and non-target screening are briefly discussed.
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| 20. |
- Kärrman, Anna, 1975-, et al.
(author)
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PFASs in the Nordic environment : Screening of Poly- and Perfluoroalkyl Substances (PFASs) and Extractable Organic Fluorine (EOF) in the Nordic Environment
- 2019
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Reports (peer-reviewed)abstract
- This report describes a screening study of in all ninety-nine conventional and emerging per- and polyfluoroalkyl substances (PFASs) in the Nordic environment. In addition, extractable organic fluorine (EOF) was analysed. The latter can provide the amount, but not identity, of organofluorine in the samples, which in turn can be used to assess the mass balance between known and unknown PFASs. The study was initiated by the Nordic Screening Group and funded by these and the Nordic Council of Ministers through the Chemicals Group. A total of 102 samples were analyzed in this study, including bird eggs, fish, marine mammals, terrestrial mammals, surface water, WWTP effluents and sludge, and air. Samples were collected by institutes from the participating countries and self-governing areas; Denmark, Faroe Islands, Finland, Greenland, Iceland, Norway, and Sweden.
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| 21. |
- Takkis, Kalev, et al.
(author)
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Signal Enhancement in the HPLC-ESI-MS/MS analysis of spironolactone and its metabolites using HFIP and NH4F as eluent additives
- 2017
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In: Analytical and Bioanalytical Chemistry. - : Springer. - 1618-2642 .- 1618-2650. ; 409:12, s. 3145-3151
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Journal article (peer-reviewed)abstract
- This paper describes an LC-MS/MS method to determine the concentration of spironolactone and its metabolites 7-alpha-methylthiospironolactone and canrenone in blood plasma samples. The resulting assay is simple (using protein precipitation for sample preparation) and sensitive (the lower limit of quantification is close to 0.5 ng/ml) while requiring only 50 mu l of plasma, making it especially suitable for analyzing samples obtained from pediatric and neonatal patients where sample sizes are limited. The sensitivity is achieved by using ammonium fluoride as an eluent additive, which in our case amplifies the signal from our analytes in the plasma solution on average about 70 times. The method is fully validated according to the European Medicines Agency's guideline and used for the measurement of pediatric patients' samples in clinical trials for evaluating oral spironolactone's and its metabolites' pharmacokinetics in children up to 2 years of age.
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| 22. |
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