Non-chlorinated Analogues Research Articles

Metal-Organic Frameworks Possessing Suitable Pores for Xe/Kr Separation.

Adsorption separation of the Xe/Kr mixture remains a tough issue since Xe and Kr have an inert nature and similar sizes. Here we present a chlorinated metal-organic framework (MOF) [JXNU-19(Cl)] and its nonchlorinated analogue (JXNU-19) for Xe/Kr separation. The two isostructural MOFs constructed from the heptanuclear cobalt-hydroxyl clusters bridged by organic ligands are three-dimensional structures. Detailed contrast of the Xe/Kr adsorption separation properties of the MOF shows that significantly enhanced Xe uptakes and Xe/Kr adsorption selectivity (17.1) are observed for JXNU-19 as compared to JXNU-19(Cl). The main binding sites for Xe in the MOF revealed by computational simulations are far away from the chlorine sites, suggesting that the introduction of the chlorine groups results in the unfavorable Xe adsorption for JXNU-19(Cl). The optimal pores, high surface area, and multiple strong Xe-framework interactions facilitate the effective Xe/Kr separation for JXNU-19.

Design of Chlorinated Indaceno[1,2-b:5,6-b']dithiophene Acceptors toward Efficient Organic Photovoltaics.

Chlorinated modifications have been extensively employed to modulate the optoelectronic properties of π-conjugated materials. Herein, the Cl substitution in designing nonfullerene acceptors (NFAs) with various bandgaps is studied. Four narrow-bandgap electron acceptors (GS-40, GS-41, GS-42, and GS-43) were synthesized by tuning the electrostatic potential distributions of the molecular conjugated backbones. The optical absorption onset of these NFAs ranges from 900 to 1030 nm. Compared to the nonchlorinated analogue, the introduction of Cl atoms on the core of indaceno[1,2-b:5,6-b'] dithiophene (IDT) and π spacer results in an upward shift of the lowest unoccupied molecular orbital levels and induces a blue shift in the absorption spectra of the NFAs. This alteration facilitates achieving appropriate energy-level alignment and favorable bulk heterojunction morphology when blended with the widely used donor PBDB-TF. The PBDB-TF:GS-43-based solar cells show an optimal power conversion efficiency of 13.3%. This work suggests the potential of employing chlorine-modified IDT and thiophene units as fundamental building blocks for developing high-performance photoactive materials.

Chlorinated benzothiadiazole-based donor-acceptor polymers with tunable optoelectronic performances

Chlorinated benzo[c][1,2,5]thiadiazole, a new analogue of benzo[c][1,2,5]thiadiazole (BT), exhibits strong electron-withdrawing ability nature, while also offering advantages of lower cost and easier accessibility compared to its fluorinated analogues. This inspires us to investigate donor-acceptor-type (D-A) conjugated polymers based on chlorinated BT. Therefore, in this work, three D-A-D type monomers (0Cl, 1Cl, and 2Cl) were successfully synthesized with BT and chlorinated BT as acceptor units and EDOT as donor units by Stille coupling reaction. Subsequently, the corresponding D-A polymers (P0Cl, P1Cl, and P2Cl) were obtained via electrochemical polymerization. The results show that the two chlorinated monomers have higher initial oxidation potentials of 1.08 V (1Cl) and 1.09 V (2Cl), which are significantly higher than their non-chlorinated analogue (0.72 V). The two chlorinated polymers demonstrate good redox activity but with relatively poor stability (only 65.7 % and 20.7 % electroactivity are preserved after 100 cycles). Due to the decreased effective conjugation length caused by the deviations from planarity, both absorption spectra of the chlorinated polymers were blue-shifted when compared with P0Cl, leading to an increase in the optical band gap (1.64–1.68 eV). Introducing the Cl atom substitution on the BT unit resulted in the improvement of both the switching time and coloration efficiency. Specifically, the monochlorinated polymer (P1Cl) showed light gray in the neutral state and obvious electrochromic properties in the near-infrared region (optical contrast: 24 %, coloration efficiency: 195.6 cm2 C−1, and quick response time: 0.4 s). This study further expands the selection of chlorinated BT-based acceptor units and the application prospect of D-A electrochromic polymers.

Ultrafast Kinetics of Chlorinated Polymer Donors: A Faster Excitonic Dissociation Path.

Halogen-substituted donor/acceptor materials are widely regarded as a promising strategy toward improved power-conversion efficiencies (PCEs) in polymer solar cells (PSCs). A chlorinated polymer donor, PClBTA-PS, and its non-chlorinated analogue, PBTA-PS, are synthesized. The PClBTA-PS-based devices show significant enhancements in terms of open-circuit voltage (VOC = 0.82 V) and fill factor (FF = 76.20%). In addition, a PCE of 13.20% is obtained, which is significantly higher than that for the PBTA-PS-based devices (PCE = 7.63%). Grazing incident wide-angle X-ray scattering shows that the chlorinated polymer enables better π-π stacking in both pure and blend films. DFT and TD-DFT calculations as well as ultrafast photophysics measurements indicate that chlorinated PClBTA-PS has a smaller bonding energy and a longer spontaneous-emission lifetime. The results also reveal that the charge-transfer-state excitons in PClBTA-PS:IT4Cl blend films split into the charge-separated (CS) state via a faster dissociation path, which produces a higher yield of the CS state. Overall, this study provides a deeper understanding of how a halogen-substituted polymer can improve PSCs in the future.

Effects of subtle change in side chains on the photovoltaic performance of small molecular donors for solar cells

Small-molecule organic solar cells (SMOSCs) have attracted considerable attention owing to the merits of small molecules, such as easy purification, well-defined chemical structure. To achieve high-performance SMOSCs, the rational design of well-matched donor and acceptor materials is extremely essential. In this work, two new small molecular donor materials with subtle change in the conjugated side thiophene rings are synthesized. The subtle change significantly affects the photovoltaic performance of molecular donors. Compared with chlorinated molecule MDJ-Cl, the non-chlorinated analogue MDJ exhibits decreased miscibility with the non-fullerene acceptor Y6, can more efficiently quench the excitons of Y6. As a result, a improved PCE of 11.16% is obtained for MDJ:Y6 based SMOSCs. The results highlight the importance of fine-tuning the molecular structure to achieve high-performance SMOSCs.

Novel Organochlorinated Xerogels: From Microporous Materials to Ordered Domains.

Hybrid silica xerogels combine the properties of organic and inorganic components in the same material, making them highly promising and versatile candidates for multiple applications. They can be tailored for specific purposes through chemical modifications, and the consequent changes in their structures warrant in-depth investigation. We describe the synthesis of three new series of organochlorinated xerogels prepared by co-condensation of tetraethyl orthosilicate (TEOS) and chloroalkyltriethoxysilane (ClRTEOS; R = methyl [M], ethyl [E], or propyl [P]) at different molar ratios. The influence of the precursors on the morphological and textural properties of the xerogels was studied using 29Si NMR (Nuclear Magnetic Resonance), FTIR (Fourier-Transform Infrared Spectroscopy), N2, and CO2 adsorption, XRD (X-ray Diffraction), and FE-SEM (Field-Emission Scanning Electron Microscopy). The structure and morphology of these materials are closely related to the nature and amount of the precursor, and their microporosity increases proportionally to the molar percentage of ClRTEOS. In addition, the influence of the chlorine atom was investigated through comparison with their non-chlorinated analogues (RTEOS, R = M, E, or P) prepared in previous studies. The results showed that a smaller amount of precursor was needed to detect ordered domains (ladders and T8 cages) in the local structure. The possibility of coupling self-organization with tailored porosity opens the way to novel applications for this type of organically modified silicates.

Voltage loss analysis of novel non-fullerene acceptors with chlorinated non-conjugated thienyl chains

Novel A-D-A type non-fullerene acceptors (NFAs) with chlorinated non-conjugated thienyl groups are designed and synthesized for the first time. The effects of chlorinated non-conjugated side thienyl groups on the absorption spectra, energy levels, photovoltaic performance, energy losses are studied. With similar absorption spectra, chlorinated NFA MAL2-sCl exhibited a higher power conversion efficiency compared with the non-chlorinated analogue MAL1. In addition, the chlorinated NFAs exhibit suppressed non-radiative energy loss. This research paves a new way to modify the photovoltaic performance and reduce the non-radiative energy loss.

Degradation of acesulfame in UV/monochloramine process: Kinetics, transformation pathways and toxicity assessment

UV/monochloramine (UV/NH2Cl) is an emerging advanced oxidation process that can generate various reactive species like reactive chlorine species (RCS) and hydroxyl radicals for micropollutant removal. This study investigated the potential toxicity of transformation products resulting from UV/NH2Cl treatment of acesulfame (ACE), as an example of micropollutant, found in worldwide aquatic environment. Compared with UV photolysis and chloramination, the UV/NH2Cl process more effectively degraded ACE. The transformation products of ACE treated with the UV/NH2Cl process were identified and characterized with high resolution mass spectrometry. The formation of chlorinated-TPs indicated the role of RCS in UV/NH2Cl transformation even though UV photolysis was predominantly responsible for the ACE degradation. The Vibrio fischeri bioluminescence inhibition assay revealed a higher toxicity of TPs derived from UV/NH2Cl than from UV photolysis. The increased toxicity could be attributed to most of the generated chlorinated-TPs (Cl-TPs), in particular those halo-alcohols. The ECOSAR program predicts that halo-alcohol TPs are more toxic than their non-chlorinated analogues and other Cl-TPs. This study provides insight into the important role of reactive species in the micropollutants’ transformation of UV/NH2Cl process. It further provides information relevant to the potential risk when applying the process for micropollutant removal in water treatment.

Chlorinated Thiophene End Groups for Highly Crystalline Alkylated Non-Fullerene Acceptors toward Efficient Organic Solar Cells

End group engineering is critical for developing A-D-A-type non-fullerene acceptors with suitable absorption properties and high crystallinity for organic solar cells. Here, we report the synthesis of a novel chlorinated thiophene end group and its application in A-D-A-type acceptors. When combined with a tetraoctyl-substituted indacenodithieno[3,2-b]thiophene core, the resulting C8-ITCC-Cl acceptor exhibited red-shifted absorption and downshifted energy levels relative to those of the nonchlorinated analogue, C8-ITCC, due to the strong electron-withdrawing ability of the chlorine atoms as revealed by theoretical calculations. Moreover, the noncovalent interactions induced by the chlorine atoms enabled improved lamellar and π–π stacking of C8-ITCC-Cl, leading to a higher electron mobility of 6.6 × 10–4 cm2 V–1 s–1 and a fill factor of 73% of the PBDB-TF:C8-ITCC-Cl devices. Consequently, a high power conversion efficiency of 12.7% was achieved by the C8-ITCC-Cl-based devices, which outperformed the C8-ITCC...

Pyridinium Oximes with Ortho-Positioned Chlorine Moiety Exhibit Improved Physicochemical Properties and Efficient Reactivation of Human Acetylcholinesterase Inhibited by Several Nerve Agents.

Six chlorinated bispyridinium mono-oximes, analogous to potent charged reactivators K027, K048, and K203, were synthesized with the aim of improving lipophilicity and reducing the p Ka value of the oxime group, thus resulting in a higher oximate concentration at pH 7.4 compared to nonchlorinated analogues. The nucleophilicity was examined and the p Ka was found to be lower than that of analogous nonchlorinated oximes. All the new compounds efficiently reactivated human AChE inhibited by nerve agents cyclosarin, sarin, and VX. The most potent was the dichlorinated analogue of oxime K027 with significantly improved ability to reactivate the conjugated enzyme due to improved binding affinity and molecular recognition. Its overall reactivation of sarin-, VX-, and cyclosarin-inhibited AChE was, respectively, 3-, 7-, and 8-fold higher than by K027. Its universality, PAMPA permeability, favorable acid dissociation constant coupled with its negligible cytotoxic effect, and successful ex vivo scavenging of nerve agents in whole human blood warrant further analysis of this compound as an antidote for organophosphorus poisoning.

Design, Synthesis and Evaluation of N-pyrazinylbenzamides as Potential Antimycobacterial Agents.

Three series of N-(pyrazin-2-yl)benzamides were designed as retro-amide analogues of previously published N-phenylpyrazine-2-carboxamides with in vitro antimycobacterial activity. The synthesized retro-amides were evaluated for in vitro growth inhibiting activity against Mycobacterium tuberculosis H37Rv (Mtb), three non-tuberculous mycobacterial strains (M. avium, M. kansasii, M. smegmatis) and selected bacterial and fungal strains of clinical importance. Regarding activity against Mtb, most N-pyrazinylbenzamides (retro-amides) possessed lower or no activity compared to the corresponding N-phenylpyrazine-2-carboxamides with the same substitution pattern. However, the active retro-amides tended to have lower HepG2 cytotoxicity and better selectivity. Derivatives with 5-chloro substitution on the pyrazine ring were generally more active compared to their 6-cloro positional isomers or non-chlorinated analogues. The best antimycobacterial activity against Mtb was found in N-(5-chloropyrazin-2-yl)benzamides with short alkyl (2h: R2 = Me; 2i: R2 = Et) in position 4 of the benzene ring (MIC = 6.25 and 3.13 µg/mL, respectively, with SI > 10). N-(5-Chloropyrazin-2-yl)benzamides with hydroxy substitution (2b: R2 = 2-OH; 2d: R2 = 4-OH) on the benzene ring or their acetylated synthetic precursors possessed the broadest spectrum of activity, being active in all three groups of mycobacterial, bacterial and fungal strains. The substantial differences in in silico calculated properties (hydrogen-bond pattern analysis, molecular electrostatic potential, HOMO and LUMO) can justify the differences in biological activities between N-pyrazinylbenzamides and N-phenylpyrazine-2-carboxamides.

A Chlorinated π-Conjugated Polymer Donor for Efficient Organic Solar Cells

Summary We synthesized a chlorinated benzothiadiazole-T4 polymer donor PBT4T-Cl, in which a chlorine atom had been introduced at the 4 position in the middle thiophene unit to fine-tune the energy level of the final polymers. Compared with its non-chlorinated analog, the PBT4T-Cl-based devices exhibited clear increases in open-circuit voltage and fill factor, achieving power conversion efficiencies (PCEs) up to 11.18% with simple synthesis, which is the highest PCE of the chlorinated polymer-based fullerene polymer solar cells (PSCs) reported to date. Grazing incident wide-angle X-ray scattering, atomic force microscopy, and transmission electron microscopy measurements revealed an optimized morphology of the spin-coated PBT4T-Cl blend films, which supported that chlorine substitution could promote the performance of PSCs. More importantly, the PBT4T-Cl-based devices showed superior stability, with a PCE of 8.16% after 50 days' device storage. Through this research, the chlorination of low-band-gap polymers provides new insight into designing π-conjugated polymer semiconductors and realizing further enhancement of polymer solar cell efficiency as well as stability.

Site of Tagging Influences the Ochratoxin Recognition by Peptide NFO4: A Molecular Dynamics Study

Molecular recognition by synthetic peptides is growing in importance in the design of biosensing elements used in the detection and monitoring of a wide variety of hapten bioanlaytes. Conferring specificity via bioimmobilization and subsequent recovery and purification of such sensing elements are aided by the use of affinity tags. However, the tag and its site of placement can potentially compromise the hapten recognition capabilities of the peptide, necessitating a detailed experimental characterization and optimization of the tagged molecular recognition entity. The objective of this study was to assess the impact of site-specific tags on a native peptide's fold and hapten recognition capabilities using an advanced molecular dynamics (MD) simulation approach involving bias-exchange metadynamics and Markov State Models. The in-solution binding preferences of affinity tagged NFO4 (VYMNRKYYKCCK) to chlorinated (OTA) and non-chlorinated (OTB) analogues of ochratoxin were evaluated by appending hexa-histidine tags (6× His-tag) to the peptide's N-terminus (NterNFO4) or C-terminus (CterNFO4), respectively. The untagged NFO4 (NFO4), previously shown to bind with high affinity and selectivity to OTA, served as the control. Results indicate that the addition of site-specific 6× His-tags altered the peptide's native fold and the ochratoxin binding mechanism, with the influence of site-specific affinity tags being most evident on the peptide's interaction with OTA. The tags at the N-terminus of NFO4 preserved the native fold and actively contributed to the nonbonded interactions with OTA. In contrast, the tags at the C-terminus of NFO4 altered the native fold and were agnostic in its nonbonded interactions with OTA. The tags also increased the penalty associated with solvating the peptide-OTA complex. Interestingly, the tags did not significantly influence the nonbonded interactions or the penalty associated with solvating the peptide-OTB complex. Overall, the combined contributions of nonbonded interaction and solvation penalty were responsible for the retention of the native hapten recognition capabilities in NterNFO4 and compromised native recognition capabilities in CterNFO4. Advanced MD approaches can thus provide structural and energetic insights critical to evaluate the impact of site-specific tags and may aid in the selection and optimization of the binding preferences of a specific biosensing element.

Combinatorial Generation of Chemical Diversity by Redox Enzymes in Chaetoviridin Biosynthesis.

Chaetoviridins constitute a large family of structurally related secondary metabolites isolated from Chaetomium fungi. To elucidate the biosynthesis pathway and understand how the chemical diversity of chaetoviridins is generated, gene deletion and in vitro characterization of the four post-PKS modifications enzymes were undertaken. CazL and CazP were identified to have substrate promiscuity that facilitates the formation of nonchlorinated analogues. In addition, enzymatic oxidation and reduction combined with spontaneous dehydration and lactonization of the intermediates further expand the chemical diversity.

NW-G12, a Novel Nonchlorinated Cyclohexapeptide from Streptomyces alboflavus 313

In our continuous investigation of metabolites of Streptomyces alboflavus 313, NW-G12 (1), a novel nonchlorinated analogue of NW-G01, was obtained as a trace constituent in the weak polarity part and a known desertomycin A (2) was also isolated from the fermentation broth in the strong polarity part. The structures of compounds 1 and 2 were established by comprehensive analysis of 1D and 2D NMR spectral data. Moreover, compounds 1 and 2 showed strong antibacterial activities against Bacillus cereus, Staphylococcus aureus, and Bacillus subtilis, with MICs of less than 10 μg/mL, but both show no antibacterial activities against two gram-negative bacteria.

Electrochemical oxidation of electrodialysed reverse osmosis concentrate on Ti/Pt–IrO2, Ti/SnO2–Sb and boron-doped diamond electrodes

Reverse osmosis concentrate from wastewater reclamation contains biorefractory trace organic contaminants that may pose environmental or health hazard. Due to its high conductivity, electrochemical oxidation of brine requires low voltage which is energetically favourable. However, the presence of chloride ions may lead to the formation of chlorinated by-products, which are likely to exert an increased toxicity and persistence to further oxidation than their non-chlorinated analogues. Here, the performance of Ti/Pt–IrO2, Ti/SnO2–Sb and Si/BDD anodes was evaluated for the electrochemical oxidation of ROC in the presence of chloride, nitrate or sulfate ions (0.05 M sodium salts). In order to investigate the electrooxidation of ROC with nitrate and sulfate ions as dominant ion mediators, chloride ion concentration was decreased 10 times by electrodialytic pretreatment. The highest Coulombic efficiency for chemical oxygen demand (COD) removal was observed in the presence of high chloride ions concentration for all anodes tested (8.3–15.9%). Electrooxidation of the electrodialysed concentrate at Ti/SnO2–Sb and Ti/Pt–IrO2 electrodes exhibited low dissolved organic carbon (DOC) (i.e. 23 and 12%, respectively) and COD removal (i.e. 37–43 and 6–22%, respectively), indicating that for these electrodes chlorine-mediated oxidation was the main oxidation mechanism, particularly in the latter case. In contrast, DOC removal for the electrodialysed concentrate stream was enhanced at Si/BDD anode in the presence of SO42− (i.e. 51%) compared to NO32− electrolyte (i.e. 41%), likely due to the contribution of SO4·− and S2O82− species to the oxidative degradation. Furthermore, decreased concentration of chloride ions lead to a lower formation of haloacetic acids and trihalomethanes at all three electrodes tested.

Nine-vertex metallaborane chemistry. Preparation and characterisation of [1,1,1-(PMe3)2H-isocloso-IrB8H7-8-X], where X = H or Cl

The heating of solutions of [(CO)(PMe3)2H-arachno-IrB8H11Cl] 1a or [(CO)(PMe3)2-nido-IrB8H10Cl] 2 in xylene results in the iridanonaborane cluster compound [1,1,1-(PMe3)2H-isocloso-IrB8H7-8-Cl] 3a in yields of up to 42%. Significantly less stable is the non-chlorinated analogue [1,1,1-(PMe3)2H-isocloso-IrB8H8] 3b, prepared via solutions of [(CO)(PMe3)2H-arachno-IrB8H12] 1b and excess nido-B10H14 in refluxing xylene. The structures of the {IrB8} units of 3a and 3b, characterised by multielement NMR spectroscopy and by single-crystal X-ray diffraction analyses, both approximate closely to an idealised C2v symmetry with the {IrH(PMe3)2} moiety capping the six-membered open faces of arachno/nido-shaped {B8} units. This structural geometry differs significantly from the classical nine-vertex closo D3h tricapped trigonal prismatic (ttp) structure of the [closo-B9H9]2− anion. NMR spectroscopy shows that both 3a and 3b are fluxional with regard to the orientation of the {Ir(H(PMe3)} ligand set relative to the {IrB8} unit. Density functional theory (DFT) calculations have been carried out to help rationalise and extend the conclusions from the experimental observations. The calculations suggest that the isocloso cluster structure for chloro-substituted 3a may be both the kinetically and the thermodynamically favoured one, whereas for unsubstituted 3b a ttp structure would be thermodynamically the more stable and so the observed isocloso structure may well be the favoured kinetic product. However, the differences in these relative stabilities are marginal, and both compounds are unstable in solution relative to a general decomposition, 3b much more so than 3a, so there may be little significance in the relative stabilities of the ttp structures: the calculations suggest that the energy barrier to an isocloso-to-ttp conversion would preclude a decomposition pathway for 3a or 3b via a ttp structure at room temperature.

Immunomagnetic microbeads for screening with flow cytometry and identification with nano-liquid chromatography mass spectrometry of ochratoxins in wheat and cereal

Multi-analyte binding assays for rapid screening of food contaminants require mass spectrometric identification of compound(s) in suspect samples. An optimal combination is obtained when the same bioreagents are used in both methods; moreover, miniaturisation is important because of the high costs of bioreagents. A concept is demonstrated using superparamagnetic microbeads coated with monoclonal antibodies (Mabs) in a novel direct inhibition flow cytometric immunoassay (FCIA) plus immunoaffinity isolation prior to identification by nano-liquid chromatography–quadrupole time-of-flight-mass spectrometry (nano-LC-Q-ToF-MS). As a model system, the mycotoxin ochratoxin A (OTA) and cross-reacting mycotoxin analogues were analysed in wheat and cereal samples, after a simple extraction, using the FCIA with anti-OTA Mabs. The limit of detection for OTA was 0.15 ng/g, which is far below the lowest maximum level of 3 ng/g established by the European Union. In the immunomagnetic isolation method, a 350-times-higher amount of beads was used to trap ochratoxins from sample extracts. Following a wash step, bound ochratoxins were dissociated from the Mabs using a small volume of acidified acetonitrile/water (2/8 v/v) prior to separation plus identification with nano-LC-Q-ToF-MS. In screened suspect naturally contaminated samples, OTA and its non-chlorinated analogue ochratoxin B were successfully identified by full scan accurate mass spectrometry as a proof of concept for identification of unknown but cross-reacting emerging mycotoxins. Due to the miniaturisation and bioaffinity isolation, this concept might be applicable for the use of other and more expensive bioreagents such as transport proteins and receptors for screening and identification of known and unknown (or masked) emerging food contaminants. FigureMicrobead coated with antibody

Identification of wastewater bacteria involved in the degradation of triclocarban and its non-chlorinated congener

Triclocarban (TCC) is an antimicrobial additive of personal care products that is only partially degraded during wastewater treatment. Bacteria responsible for its transformation are unknown. We obtained wastewater bacteria capable of using as the sole carbon source TCC or its non-chlorinated analog, carbanilide (NCC). Enrichments established using activated sludge amended with TCC and NCC, respectively, were maintained for 1 year through successive transfers. Enrichments displayed exponential growth after 2 weeks, reaching stationary phase after 1 month. The NCC enrichment was shown to accumulate aniline. Denaturing gradient gel electrophoresis of amplified 16S rRNA genes indicated markedly reduced community richness compared to the inoculum and a single, prominent taxonomic unit emerged in both chlorinated and non-chlorinated carbanilide enrichment cultures. Cloned 16S rRNA genes showed both enrichments were dominated by a single genotype related to uncharacterized organisms within the Alcaligenaceae. Of ∼30 sequences from each enrichment, no other organisms were detected in the TCC enrichment while, a small, flanking community of alpha proteobacteria was detected in the NCC enrichment. Study results demonstrate that growth of wastewater bacteria on TCC and its lower chlorinated analog can be linked to bacteria within the family Alcaligenaceae. These organisms are promising agents for the bioremediation of hazardous phenylurea pollutants.

Ochratoxin A in Roasted Coffee from French Supermarkets and Transfer in Coffee Beverages: Comparison of Analysis Methods

The OTA content of 30 roasted coffees purchased in French supermarkets was evaluated by two validated different methods: one using immunoaffinity column (IAC) clean-up after alkaline extraction; the second using toluene extraction under acidic conditions. OTA recoveries (0.5 to 5 µg/kg) ranged from 16–49% with the alkaline extraction method and 55–60% with the acidic method. OTA recoveries from prepared beverages were similar with all methods (75–80%). All samples containing OTA ranged from trace (<LOQ) to 11.9 µg/kg. About 20 to 140% of OTA passed through the beverages. Recoveries of over 100% of OTA in beverages were due to three types of interferences: (i) formation of open-ring OTA (OP-OA) during alkaline extraction, (ii) isomerization of OTA during roasting, and (iii) presence of the nonchlorinated analogue OTB. The first two types of interference generate OTA derivatives that are not recognized by OTA antibodies, while OTB cross-reacts with OTA-antibodies. These analytical problems will seriously impact the amount of OTA detected, especially at the levels close to the limits from the EU legislation. Underestimation of OTA could be highly dangerous for health.