Phosphate Diester Research Articles

A Hexanuclear Gallium(III) Complex with a {GaIII6(μ‐OH)10} Core Supported by two Naphthalenediolate‐Based Ligands

We have developed a family of 2,7‐disubstituted 1,8‐naphthalenediol ligands to pre‐organize two metal ions to the distance of two neighboring phosphate diesters of 6‐7 Å in the DNA backbone by a rigid backbone. As complexes with divalent ions (CuII and NiII) bind to DNA, interferes DNA synthesis via PCR, and kills human cancer cells more efficiently than human stem cells of the same proliferation rate, we intended to increase the binding affinity by going from divalent to trivalent ions ‐ especially FeIII. Here, we apply GaIII as redox inactive model for FeIII and obtain for the first time a complex with trivalent ions. However, the structural characterization provides not a dinuclear GaIII complex, but a hexanuclear GaIII complex with a central {GaIII6(m‐OH)10} core, that is yet unprecedented.

Perfluoroalkyl acid precursor or weakly fluorinated organic compound? A proof of concept for oxidative fractionation of PFAS and organofluorines.

Organofluorine mass balance approaches are increasingly applied to investigate the occurrence of per- and polyfluoroalkyl substances (PFAS) and other organofluorines in environmental samples more comprehensively. Usually, complex samples prevent the identification and quantification of every fluorine-containing molecule. Consequently, large unidentified fractions between fluorine sum parameters such as extractable organic fluorine (EOF) and the sum of quantified analytes are frequently reported. We propose using oxidative conversion to separate (unidentified) weakly fluorinated compounds (e.g., pesticides, pharmaceuticals) from PFAA-precursors (perfluoroalkyl chain lengths ≥ C6). We show with three organofluorine model substances (flufenamic acid, diflufenican, pantoprazole) that CF3-groups or aromatic fluorine can be quantitatively converted to inorganic fluoride and trifluoroacetic acid (TFA) by applying PhotoTOP oxidation (UV/TiO2). The principle of fluorine separation in mixtures is demonstrated by the oxidation of the three weakly fluorinated compounds together with the PFAA-precursor 6:2/6:2 fluorotelomer mercaptoalkyl phosphate diester (FTMAP). After oxidation, the products F- and TFA were separated from PFCAs (> C4) by SPE, and the fractions were analyzed individually. Closed mass balances both with and without the addition of organic matrix were achieved. Eventually, the fluorine balance was verified by total fluorine measurements with combustion ion chromatography (CIC). The proposed methods should be considered a proof of concept to potentially explain unidentified fractions of the EOF, especially if compounds with low fluorine content such as pesticides, pharmaceuticals, and their transformation products contribute largely to the EOF. Future studies are needed to show the applicability to the complexity of environmental samples.

6669 Association Between Serum Levels of Thyroid Function and Per- and Polyfluoroalkyl Compounds Concentrations in Central Precocious Puberty in Girls

Abstract Disclosure: Y. Li: None. Y. Xing: None. X. Yin: None. J. Yang: None. S. Zang: None. T. Dong: None. Y. Pan: None. J. Dai: None. P. Li: None. Background: Exposure to per- and polyfluoroalkyl substances (PFASs) may interfere with thyroid function in the general population and disturb the timing of puberty onset. Objectives: We investigated the possible relationship between PFASs and thyroid hormone (THs) exposure in girls with central precocious puberty (CPP). Methods: In a prospective study initially established for assessing CPP, 627 serum samples were collected with (n = 226) and without (n = 401) CPP. The concentrations of 25 PFASs, thyroxin (T4), 3,5,3’-triiodothyronine (T3), and 3,3’,5’-triiodothyronine (rT3) were measured. We used logistic regression to examine the association of THs with the odds of having CPP and multiple linear regression to analyze the associations between THs and various PFASs in the CPP and control groups. Results: The levels of T4 in the CPP group were significantly lower than those in the control group, and the levels of T3 and rT3 were significantly higher than those in the control group. After adjusting for confounders, T3 concentrations were associated with 1.526-fold increased odds of having CPP [odds ratio (OR) = 1.526, 95% confidence interval (CI):1.216-1.914]. In the CPP cohort, perfluoroheptanoic acid (PFHpA), perfluoro (2-ethoxyethane) sulphonic acid (PFEESA), and fluorotelomer phosphate diester (6:2/8:2 diPAP) were inversely associated with T3; perfluorobutanoic acid (PFBA) was inversely associated with T4, and PFEESA and 6:2/8:2 diPAP positively associated with T4; PFBA was positively associated with rT3, and perfluorooctane sulfonic acid (PFOS) was inversely associated with rT. In the control cohort, perfluorobutanesulfonic acid (PFBS) was positively associated with T3, and PFEESA and 6:2/8:2 diPAP were inversely associated with T3, and these PFASs had an adverse association with T4. Perfluorohexanoic acid (PFHxA) was positively associated with rT3, and 6:2/8:2 diPAP was negatively associated with rT3. Conclusion: In this study, different measurements of PFASs and THs were observed in the CPP and control groups. Discrepancies in exposure to PFASs were associated with THs in the CPP cohort and healthy girls. Further research is necessary to investigate the mechanism by which PFASs affect the timing of puberty onset and thyroid function. Presentation: 6/1/2024

Impacts of rapidly urbanizing watershed comprehensive management on per- and polyfluoroalkyl substances pollution: Based on PFAS “diversity” assessment

The impact of watershed comprehensive management (WCM) on per- and polyfluoroalkyl substances (PFAS) pollution in rapidly urbanizing areas remains unclear. In a typical rapidly urbanizing watershed of Shenzhen, China, we investigated temporal variations in contamination level, primary source and ecological risk of 50 emerging and legacy PFAS, as well as the replacement trends of emerging PFAS before and after WCM during a six-year sampling campaign. We found that large-scale dredging was a non-negligible factor in abnormally increased PFAS concentrations (6.43 %–456.16 %) during WCM through their release from river sediments. To better characterize the diverse and complex PFAS contamination, a novel pollution assessment method, PFAS “diversity”, was adopted based on a modified Shannon–Weiner diversity index and Pielou evenness index, reflecting numbers of PFAS detected and how evenly each PFAS contributed to the total PFAS concentrations at specific sampling sites. Importantly, we found that the Pielou evenness index can indicate and quantify abnormal pollution sources (especially point sources) along the river. The results revealed that WCM did not effectively reduce total PFAS concentrations and diversity in the rapidly urbanizing watershed but obviously improved point source pollution. Furthermore, 6:2 polyfluorinated phosphate diesters and hexafluoropropylene oxide dimer acid (GenX) that posed high ecological risks emerged and the number of sampling sites with high risk increased from 16 to 20 after WCM. Finally, we summarize several important issues related to PFAS contamination during WCM and propose specific countermeasures, such as adopting environmental dredging and reducing the proportion of ecological water replenished by wastewater treatment plant effluent for better control of PFAS pollution. Our study highlighted the limited effectiveness of WCM in mitigating PFAS pollution and the importance of emerging contaminant regulation in rapidly urbanizing watersheds during WCM.

Non-targeted analysis of per- and polyfluorinated substances in consumer food packaging

This study sought to develop a non-targeted workflow using high-resolution mass spectrometry (HRMS) to investigate previously unknown PFAS in consumer food packaging samples. Samples composed of various materials for different food types were subjected to methanolic extraction, controlled migration with food simulants and total oxidizable precursor (TOP) assay. The developed HRMS workflow utilized many signatures unique to PFAS compounds: negative mass defect, diagnostic breakdown structures, as well as retention time prediction. Potential PFAS features were identified in all packaging studied, regardless of food and material types. Five tentatively identified compounds were confirmed with analytical standards: 6:2 fluorotelomer phosphate diester (6:2 diPAP) and one of its intermediate breakdown products 2H-perfluoro-2-octenoic acid (6:2 FTUCA), perfluoropentadecanoic acid (PFPeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA). Longer perfluorocarboxylic acids including C17 and C19 to C24 were also found present within a foil sample. Concentrations of 6:2 FTUCA ranged from 0.78 to 127 ng g−1 in methanolic extracts and up to 6 ng g−1 in food simulant after 240 h migration test. These results demonstrate the prevalence of both emerging and legacy PFAS in food packaging samples and highlight the usefulness of non-targeted tools to identify PFAS not included in targeted methods.

Effects and Mechanism of Hyperbranched Phosphate Polycarboxylate Superplasticizers on Reducing Viscosity of Cement Paste.

The adsorption behavior and dispersing capability of hyperbranched phosphated polycarboxylate superplasticizers (PCEs) containing phosphate monoester and phosphate diester were investigated. The hyperbranched structures were constructed using a special monomer dimethylaminoethyl methacrylate (DMAMEA) to create the branches during the polymerization. Meanwhile, the polymer architectures were tailored by varying the content of phosphate monoester and phosphate diester in the backbone via free radical solution polymerization. In contrast to comb-like PCE, hyperbranched PCEs presented a weaker dispersion capability at w/c = 0.29, but with a lower water-to-cement ratio (w/c), the hyperbranched PCEs exhibited a better dispersion capability than the comb-like PCEs. The dynamic light scattering (DLS) and transmission electron microscope (TEM) analysis showed that the adsorption layer of hyperbranched PCEs were thicker than that of comb-like PCEs. A thicker adsorption layer thickness generated thinner diffusion water layer thickness. The increase of the free water amount due to the thinner water diffusion layer is the key mechanism for improving the dispersibility and decreasing the viscosity of cement paste.

Investigating the sources and fate of per- and polyfluoroalkyl substances (PFAS) in food waste compost

Composting municipal food waste is a key strategy for beneficially reusing methane-producing waste that would otherwise occupy landfill space. However, land-applied compost can cycle per- and polyfluoroalkyl substances (PFAS) back into the food supply and the environment. We partnered with a pilot-scale windrow composting facility to investigate the sources and fate of 40 PFAS in food waste compost. A comparison of feedstock materials yielded concentrations of ∑PFAS under 1 ng g−1 in mulch and food waste and at 1380 ng g−1 in leachate from used compostable food contact materials. Concentrations of targeted ∑PFAS increased with compost maturity along the windrow (1.85–23.1 ng g−1) and in mature stockpiles of increasing curing age (12.6–84.3 ng g−1). Among 15 PFAS quantified in compost, short-chain perfluorocarboxylic acids (PFCAs) – C5 and C6 PFCAs in particular – led the increasing trend, suggesting biotransformation of precursor PFAS into these terminal PFAS through aerobic decomposition. Several precursor PFAS were also measured, including fluorotelomer carboxylic acids (FTCAs) and polyfluorinated phosphate diesters (PAPs). However, since most targeted analytical methods and proposed regulations prioritize terminal PFAS, testing fully matured compost would provide the most relevant snapshot of PFAS that could be land applied. In addition, removing co-disposed food contact materials from the FW feedstock onsite yielded only a 37 % reduction of PFAS loads in subsequent compost, likely due to PFAS leaching during co-disposal. Source-separation of food contact materials is currently the best management practice for meaningful reduction of PFAS in food waste composts intended for land application.

Transformation, leaching and plant uptake simulations of 6:2 and 8:2 polyfluoroalkyl phosphate diesters (diPAPs) and related transformation products under near-natural conditions

In response to the growing concern over PFAS contamination, employing models to simulate PFAS behavior in the environment becomes necessary. This facilitates evaluating risks tied to leaching into groundwater, adsorption in soil, plant uptake, entry into the food chain, and the conversion of precursors into persistent PFAS. We utilized the MACRO model to simulate the behavior of the precursors 6:2 diPAP and 8:2 diPAP using data from a 2-year lysimeter experiment, key compound parameters were optimized via the caRamel evolutionary algorithm. We assumed that the transformation of both diPAP precursors into stable PFAAs is influenced by temperature and soil moisture, similar to pesticide degradation by microorganisms. Results reveal that the model accurately represents transformation, leaching, soil retention, and plant uptake of diPAP and transformation products. A comparison with a lab-based soil column study supports the slower natural degradation of precursors, affirming our modeling approach. Temperature and soil moisture could indicate that a worst-case scenario for transformation product leaching into groundwater could occur during a mild summer with moderate evapotranspiration and heavy rainfall. Plant uptake involves multiple elements: PFAS availability in the root zone depends on prior degradation or presence. Increased moisture in the root zone favors PFAS uptake combined with temperatures high enough for prior biotransformation. The calculation of temperature and moisture-based conversion rates was adopted directly from MACRO. It is recommended to further investigate these effects to validate and possibly modify them.

Mechanism of organic phosphorus transformation and its impact on the primary production in a deep oligotrophic plateau lake during stratification

Global warming is leading to extended stratification in deep lakes, which may exacerbate phosphorus (P) limitation in the upper waters. Conversion of labile dissolved organic P (DOP) is a possible adaptive strategy to maintain primary production. To test this, the spatiotemporal distributions of various soluble P fractions and phosphomonesterase (PME)/phosphodiesterase (PDE) activities were investigated in Lake Fuxian during the stratification period and the transition capacity of organic P and its impact on primary productivity were evaluated. The results indicated that the DOP concentration (mean 0.20 ± 0.05 μmol L−1) was significantly higher than that of dissolved inorganic P (DIP) (mean 0.08 ± 0.03 μmol L−1) in the epilimnion and metalimnion, which were predominantly composed of orthophosphate monoester (monoester-P) and orthophosphate diesters (diester-P). The low ratio of diester-P / monoester-P and high activities of PME and PDE indicate DOP mineralization in the epilimnion and metalimnion. We detected a DIP threshold of approximately 0.19 μmol L−1, corresponding to the highest total PME activity in the lake. Meta-analysis further demonstrated that DIP thresholds of PME activities were prevalent in oligotrophic (0.19 μmol L−1) and mesotrophic (0.74 μmol L−1) inland waters. In contrast to the phosphate-sensitive phosphatase PME, dissolved PDE was expressed independent of phosphate availability and its activity invariably correlated with chlorophyll a, suggesting the involvement of phytoplankton in DOP utilization. This study provides important field evidence for the DOP transformation processes and the strategy for maintaining primary productivity in P-deficient scenarios, which contributes to the understanding of P cycles and the mechanisms of system adaptation to future long-term P limitations in stratified waters.

Hepatotoxicity and lipid metabolism disorders of 8:2 polyfluoroalkyl phosphate diester in zebrafish: In vivo and in silico evidence

8:2 polyfluoroalkyl phosphate diester (8:2 diPAP) has been shown to accumulate in the liver, but whether it induces hepatotoxicity and lipid metabolism disorders remains largely unknown. In this study, zebrafish embryos were exposed to 8:2 diPAP for 7 d. Hepatocellular hypertrophy and karyolysis were noted after exposure to 0.5 ng/L 8:2 diPAP, suggesting suppressed liver development. Compared to the water control, 8:2 diPAP led to significantly higher triglyceride and total cholesterol levels, but markedly lower levels of low-density lipoprotein, implying disturbed lipid homeostasis. The levels of two peroxisome proliferator activated receptor (PPAR) subtypes (pparα and pparγ) involved in hepatotoxicity and lipid metabolism were significantly upregulated by 8:2 diPAP, consistent with their overexpression as determined by immunohistochemistry. In silico results showed that 8:2 diPAP formed hydrogen bonds with PPARα and PPARγ. Among seven machine learning models, Adaptive Boosting performed the best in predicting the binding affinities of PPARα and PPARγ on the test set. The predicted binding affinity of 8:2 diPAP to PPARα (7.12) was higher than that to PPARγ (6.97) by Adaptive Boosting, which matched well with the experimental results. Our results revealed PPAR - mediated adverse effects of 8:2 diPAP on the liver and lipid metabolism of zebrafish larvae.

Intensive agricultural management-induced subsurface accumulation of water-extractable colloidal P in a Vertisol

Abstract. Long-term excessive application of mineral fertilizer leads to phosphorus (P) accumulation, increasing the risk of P migration and loss from the soil profile. The colloids in the soil profile are important carriers for P migration due to their high P adsorption and transport capacity. It is not clearly understood how colloidal P (CP) is distributed in subsoils (<1.2 m) of a Vertisol, contributing to subsurface P loss. Understanding the depth sequence distribution and speciation of colloidal P in the soil profile is critical for a comprehensive assessment of P loss. In this study, water-extractable colloids (WECs) with the size of 0.35–2 µm were obtained from a 0–120 cm soil profile by a sedimentation and centrifugation scheme. The dissolved reactive P (DRP) and dissolved total P (DTP) in soil supernatant with particle sizes <0.35 µm were measured by molybdate blue colorimetry. Solution 31P nuclear magnetic resonance (NMR) and P K-edge XANES (X-ray absorption near-edge structure) were used to characterize the species and distribution of CP in the soil profile of fertilized farmland. Total and available P in bulk soil and colloids decreased with soil depth. The organic P (OP) contained 97–344 mg kg−1 per bulk soil and 110–630 mg kg−1 per WEC. The OP in soil profile consists of orthophosphate mono-esters and diesters primarily according to NMR results. It suggested that OP in WECs from subsoils might be affected by the translocation of CP from surface soils, probably due to soil acidification and preferential flow caused by swelling–shrinkage clays, including montmorillonite and nontronite detected by X-ray powder diffractometer (XRD) results. Additionally, the more negative zeta potential of surface soil colloids suggests the high mobility of colloidal P towards the subsoils. The CP concentration for <2 µm was about 38–93 mg P kg−1 per bulk soil, which is 6–37 times that of DRP, suggesting that CP plays a dominant role in P transport within the soil profile. The relatively small fraction of orthophosphate diesters suggests limited P assimilation by microorganisms for the accumulation of WECs containing organically bound P in subsoils. The P K-edge XANES results indicated that the proportions of Al-P, Fe-P, and inositol hexakisphosphate (IHP) of WECs decreased, but hydroxyapatite (HAP) increased with soil depth. This study showed that inorganic and organic P migrated from the surface to deeper layers along the soil profile, with soil colloids having a significant effect on P migration from both surface and subsurface layers. The findings have an important significance for soil P migration evaluation and agricultural non-point source pollution control in Vertisols.

Genomics and metabolic characteristics of simultaneous heterotrophic nitrification aerobic denitrification and aerobic phosphorus removal by Acinetobacter indicus CZH-5

This study provides for the first time a systematic understanding of Acinetobacter indicus CZH-5 performance, metabolic pathway and genomic characteristics for aerobic nitrogen (N) and phosphorus (P) removal. Acinetobacter indicus CZH-5 showed promising performance in heterotrophic nitrification aerobic denitrification and aerobic phosphorus removal. Under optimal conditions, the maximum ammonia-N, total nitrogen and orthophosphate-P removal efficiencies were 90.17%, 86.33%, and 99.89%, respectively. The wide tolerance range suggests the strong environmental adaptability of the bacteria. The complete genome of this strain was reconstructed. Whole genome annotation was used to re-construct the N and P metabolic pathways, and related intracellular substance metabolic pathways were proposed. The transcription levels of related functional genes and enzyme activities further confirmed these metabolic mechanisms. N removal was achieved via the nitrification–denitrification pathway. Furthermore, CZH-5 exhibited significant aerobic P uptake, with phosphate diesters as the main species of intracellular P.

Modelling the Binding of Cytotoxic Dinuclear Copper Complexes to two Neighboring Phosphate Esters of DNA Using Glutarate: A Tetranuclear Metallo‐Macrocycle vs a Dinuclear Model

AbstractA family of dinuclear complexes was rationally designed to bind to two neighboring phosphate diesters of DNA by molecular recognition. Although these complexes bind strongly and irreversibly to DNA and induce apoptosis in cancer cells, a direct proof of the intended binding mode is missing. To mimic two neighboring phosphate diesters of DNA, we use here the dicarboxylate glutarate as a difunctional ligand. Starting from the acetate‐bound CuII2 complex, protonation results in the de‐coordination of acetate and allows the synthesis of the glutarate‐bound complex. Instead of bridging two CuII ions of one dinuclear complex, two glutarates bridge two dinuclear complexes resulting in a tetranuclear metallo‐macrocycle. The molecular structures of two different salts differ in the square‐pyramidal coordination to the CuII ions. The carboxylate stretching modes, the d‐d and the CT transtitions are not sensitive enough to resolve these differences. The exchange coupling is weakly antiferromagnetic between the CuII ions in the dinuclear subunits and negligible between the subunits via the glutarates. The consequences for suited ligands to model the binding to two neighboring phosphate diesters in the DNA backbone is discussed.

Efficient phenyl phosphate ester extractant synthesis and solvent extraction performance evaluation for transition metals

The extraction performance of traditional acidic phosphate ester extractants (P204 and P507) will decrease sharply as the aqueous-phaseacidity increases. Although saponification pretreatment can maintain the stability of aqueous-phase acidity during solvent extraction, allowing for the efficient extraction of target metals, it also generates a large amount of salt-contaminated wastewater. Thus, an acid-resistant phenyl phosphate ester extractant was synthesized based on the conjugated effect of the benzene ring, and the impact of synthesis temperature on its structural composition and extraction performance was studied. The molecular structures of the synthesized products were determined as [(CH3)3CCH2C(CH3)2C6H4O]2P(=O)OH (phosphate di-ester, DAP) and (CH3)3CCH2C(CH3)2C6H4OP(=O)(OH)2 (phosphate mono-ester, MAP) through FT-IR, NMR, and HRMS characterization. The extraction rates of Ni2+, Co2+, and Mn2+ by DAP/MAP synthesized at 75 °C were 57.58 %, 69.42 %, and 75.70 %, respectively, without saponification pretreatment. Under the same conditions, the extraction rates of Ni2+, Co2+, and Mn2+ by P204 were 21.16 %, 16.11 %, and 19.31 %, while those by P507 were 22.79 %, 9.05 %, and 11.31 %, respectively. The density functional theory (DFT) calculations indicate that P = O and P-OH groups are the active centers of the DAP/MAP coordination reaction with metal ions. The Gibbs free energy changes during extraction reveal the performance difference between DAP and MAP (sequence: DAP > MAP). The order of coordination ability of the three transition metal ions with DAP and MAP is Mn2+ > Co2+ > Ni2+, consistent with the experimental data.

Crops use inorganic and labile organic phosphorus from both high‐ and low‐availability layers in no‐till compost‐amended soils

AbstractOrganic fertilization in no‐till soils increases soil organic matter and nutrient pools primarily in surface soils. However, little is known about how microbial activity affects crop access to phosphorus (P) forms at the surface, where the organic fertilizer is applied, and the subsurface, the main rooting zone. We aimed to study the changes in organic and inorganic P (Po; Pi) forms and compounds in no‐till compost amended surface (0–5 cm) and subsurface (5–15 cm) soils growing a crop rotation for 2 years in pots. Crops were grown in pots with compost amended to the soil surface, while unamended and compost‐amended pots without crops were used as controls. We measured changes in microbial C (carbon), soluble C, total Po and Pi forms, the moderately accessible EDTA‐NaOH‐Pi (‐Po), and labile NaHCO3‐Pi (‐Po). P compounds in the EDTA‐NaOH extract were measured by 31P‐NMR. Compost addition increased the levels of total Pi and although it had no effect on total Po, increases of inositol, other phosphate monoesters and orthophosphate diesters could be observed. After the application of compost, the amount of total organic C, soluble carbon and all P forms increased in surface soil, while in the subsurface soil, there was a reduction in organic C and an increase in soluble C, total Pi, EDTA‐NaOH‐Pi and NaHCO3‐Pi and the EDTA‐NaOH‐Po and labile NaHCO3‐Po. Growing crops reduced all measured Pi forms and labile NaHCO3‐Po, increased EDTA‐NaOH‐Po in surface soils and had no observable impact on total Po in either organic C‐enriched surface or organic C‐reduced subsurface soils. Crops mostly used Pi from the low P availability C‐reduced subsurface layer, where NaHCO3‐Po pools also decreased. Large reductions in NaHCO3‐Po and increased levels of IHP and other‐monoesters in crop‐growing organic C‐enriched surface layers may suggest microbial formation of monoesters Po and crop use of labile Po pools. In summary, Po formation in C‐enriched surface layers and the mobilization of all Pi forms throughout the soil profile are particularly important findings for the understanding of P dynamics in compost‐amended no‐till systems.

Chemical Dephosphorylation of Phosphorylated Polysaccharide.

In exocellular polysaccharides produced from lactic acid bacteria with bioactivity, phosphate groups in polysaccharide have been found to act as an active factor. This chapter introduces chemical dephosphorylation using HF by cleaving phosphate diester bonds in extracellular polysaccharides to clarify phosphorus group functions. After this operation, the purified dephospho-polysaccharide can be used for evaluation of bioactivity.

Hydrolysis of phosphate diester catalyzed by new mononuclear copper(II) complexes containing selenium ligands

AbstractThree new copper(II) mononuclear complexes containing different organoselenium groups (1–3) were synthesized and characterized by the following techniques: elemental analysis, IR and UV‐Vis spectroscopies, electrochemical and conductimetric analysis, and mass spectrometry. Three new complexes, with substituents made in the para position of the aromatic portion of the N,N‐bis(2‐(phenylselanyl)ethyl)amine ligand: p‐OCH3 (1), p‐CH3 (2), and p‐Cl (3), were synthetized to compare with the already published complex (4), with no substituents. The ligand coordinates to the copper(II) center in a tridentate way with Se, N, Se as donor atoms. The hydrolytic activity in phosphate diester cleavage of the complexes was investigated using 2,4‐BDNPP as substrate. The modifications in the ligand are reflected in the difference between the catalytic and activation parameters, where the kcat values follow the order: 4 > 2 > 3 > 1.

Simultaneous inorganic nitrogen and phosphate removal by aerobic-heterotrophic fungus Fusarium keratoplasticum FSP1: Performance, pathway and application

Fungi with multiple contaminant removal function have rarely been studied. Here, a novel fungal strain Fusarium keratoplasticum FSP1, which was isolated from halophilic granular sludge, is reported for first time to perform simultaneous nitrogen and phosphate removal. The strain showed wide adaptability under C/N ratios of 30–35, salinities of 0 %–3 % (m/v), and pH of 7.5–9.5. The maximum removal rates of ammonium, nitrate and nitrite were 4.43, 4.01 and 2.97 mg N/L/h. The nitrogen balance, enzyme activity and substrate conversion experiments demonstrated a single strain FSP1 can assimilate inorganic nitrogen and convert inorganic nitrogen to gaseous nitrogen through heterotrophic nitrification or aerobic denitrification. About 39 %–42 % of the degraded phosphorus was in the extracellular polymeric substances (EPS). Orthophosphate was the main phosphorus species in the cell, whereas phosphate monoester and diester were in the EPS. The novel strain FSP1 is a potential candidate for wastewater treatment.

The Hydrolytic Activity of Copper(II) Complexes with 1,4,7-Triazacyclononane Derivatives for the Hydrolysis of Phosphate Diesters.

A set of substituted 1,4,7-triazacyclononane ligands was synthesised, including a wide series of novel derivatives bearing a thiazole or thiophene side group, with the potential to incorporate these derivatives into a polymeric material; some previously known/studied ligands were also synthesised for comparative purposes. The corresponding copper(II) complexes were prepared, and their ability to mediate the hydrolysis of phosphate ester bonds was studied via UV-Vis spectrophotometry, using bis(p-nitrophenyl)phosphate as a model substrate. Some of the prepared complexes showed a considerable enhancement of the phosphate ester hydrolysis in comparison with previously studied systems, which makes them some of the most effective complexes ever tested for this purpose. Therefore, these novel, potentially bifunctional systems could provide the possibility of creating new coating materials for medicinal devices that could prevent biofilm formation.

Analysis of per- and polyfluoroalkyl substances in plastic food storage bags by different analytical approaches

In this study, consumer and lab grade plastic food storage bags were subjected to a variety of analytical techniques to investigate the presence and levels of per- and polyfluoroalkyl substances (PFAS). Samples were extracted and analyzed by both targeted and non-targeted analyses using liquid chromatography tandem mass spectrometry and Orbitrap high resolution mass spectrometry. Of the 18 bags tested, 57 % had detectable levels of PFAS ranging from 0.5 – 26.6 ng/g. Perflurorobutane sulfonic acid (PFBS) was detected at the highest concentration while 6:2 fluorotelomer phosphate diester (6:2 diPAP) was the most frequently detected. No other PFAS were found in the targeted method. Non-targeted analysis resulted in six potential new PFAS candidates not found within the targeted method, however the lack of available analytical standards did not allow for confirmation. Eight samples with detectable PFAS were chosen for both migration and total oxidizable precursor (TOP) assay experiments to understand the potential impact to dietary exposure. No 6:2 diPAP was found to migrate however migration of PFBS was found to be rapid (2 h) and with relatively high migration efficiencies (22 – 75 %). To estimate potential exposure to PFBS migrating from food storage bags, tolerable weekly intake (TWI) values were calculated at 2.12 ng/kg body weight/week, and were below the regulatory TWI value of 4.4 ng/kg established by the European Food Safety Authority (EFSA).