Main Degradation Products Research Articles

Non-target metabolomics approach for the investigation of the hidden effects induced by atrazine and its degradation products on plant metabolism

Japanese radish (Raphanus sativus var. longipinnatus) plants grown under laboratory conditions were individually exposed to the same doses of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine, ATR) or its main degradation products: either 2-amino-4-chloro-6-isopropylamino-1,3,5-triazine (DEA) or 2-amino-4-chloro-6-ethylamino-1,3,5-triazine (DIA) or desethyl-desisopropyl-atrazine (DEDIA) or 4-(ethylamino)-2-hydroxy-6-(isopropylamino)-1,3,5-triazine (HA), respectively. One week after treatment in plants exposed to ATR, DIA, and DEA, their concentrations were 7.8 μg/g, 9.7 μg/g, and 14.5 μg/g, respectively, while those treated with DEDIA and HA did not contain these compounds. These results were correlated with plant amino acid profile obtained by suspect screening analysis and metabolomic “fingerprint” based on non-target analysis, obtained by liquid chromatography coupled with QTRAP triple quadrupole mass spectrometer. In all cases, both ATR and its by-products were found to interfere with the plant's amino acid profile and modify its metabolic “fingerprint”. Therefore, we proved that the non-target metabolomics approach is an effective tool for investigating the hidden effects of pesticides and their transformation products, which is particularly important as these compounds may reduce the quality of edible plants.

Environmentally safe chemometric evaluation and data analysis for the kinetic investigation of mirabegron stability

The physicochemical characteristics of different pharmaceuticals may change with transportation, storage, and usage which directly affect their efficacy, quality, and other features. It is crucial to investigate the kinetic action of pharmaceutical compounds to produce predictive data that aid in the computation of their shelf lives. Several conventional analytical methods introduce unwanted dangerous risks, like employing unsafe solvents, that harm both the analyst and the environment. This created the motive for analysts to apply green approaches that consider using safe chemicals and producing as little waste as possible. In this study, powerful green assessment methods were investigated to study the kinetic process of Mirabegron (MIR) in different hydrolytic conditions giving its main degradation product. First, the optimal solvent was identified for the given kinetic procedures with the aid of Principal Component Analysis. Then two advanced chemometric methods were applied to estimate the kinetic parameters of the MIR degradation process namely: Multivariate Curve Resolution-Alternating Least Squares and Artificial Neural Networks. By data manipulation, both algorithms could provide an explanation of the MIR kinetic process in different hydrolytic conditions. Moreover, modified National Environmental Methods Index (NEMI), eco-scale, Hexagon algorithm, Complementary Green Analytical Procedure Index (Complex GAPI), and analytical greenness metric for sample preparation (AGREEprep) were adopted to ensure the greenness of the proposed study. Eventually, the presented investigation could successfully present an eco-friendly chemometric approach for monitoring the different kinetic processes of pharmaceutical compounds with minimum effort and solvent consumption and maximum time saving and analyst safety compared to other traditional methods.

Supported heterogeneous catalyst of the copper oxide nanoparticles and nanozeolite for binary dyes mixture degradation: Machine learning and experimental design

The present work aims to evaluate the photocatalytic activity of an alternative supported nanocatalyst (nANA@CuO-NPs) for a binary dye mixture (Crystal Violet and Methylene Blue, labeled CV:MB) under visible light and study to propose a model to predict the reaction pathway for the process. An experimental design (Central Composite Rotational Design with 3 factors and 2 levels – CCRD 23) was proposed to evaluate the ideal condition of the CV/MB photodegradation and four machine learning algorithms (Decision Tree, Random Forest, Xtreme Gradient Boosting and Artificial Neural Network-Multilayer Perceptron) were used to predict the main degradation products. The supported nanocatalyst was characterized by X-ray diffraction (XRD), Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, N2 porosimetry, Diffuse Reflectance Spectroscopy (DRS), Field Emission Gun – Scanning Electron Microscope (FEG-SEM), Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), zeta potential (ZP) and zero charge point (pHZCP). XRD diffractogram of the nANA@CuO-NPs showed the tenorite and analcime phases with crystallite size and microstrain ranging from 0.319 to 22.35 nm and 6.48–454 × 10−3. ATR-FTIR spectra indicated the presence of functional groups characteristic of copper oxide nanoparticles (CuO-NPs) and nanozeolite analcime (nANA) on the supported catalyst, confirming the impregnation method. SEM micrographs indicated a heterogeneous surface with clusters (CuO-NPs and nANA@CuO-NPs) and homogenous surface for nANA, while the EDX showed the nANA with Si/Al < 2 (low-silica nanozeolite) and nANA@CuO-NPs with the presence in the elemental composition of the catalytic support (nANA) and the photoactive phase (CuO-NPs). Supported nanocatalyst showed physio-chemical stability due to the electrostatic interactions (ZP = 51.5 ± 0.5 mV) and band gap energy (Eg) of the 1.67 eV allowing its applicability under visible radiation. XGB algorithm resulted in the best predictive model (R2 equals 0.8106 and 0.9880 for training and testing, RMSE < 6.0), confirming the obtention of carbon dioxide (m/z = 44), water (m/z = 18) and low-molar mass compounds at the final of the binary dye mixture degradation reaction. The ideal condition for the by CCRD 23 for the degradation of the dye mixture was [CV:MB] = 135 mg/L, [nANA@CuO-NPs] = 1 g/L and pH = 7 with 82.84 % (k = 0.0089 min−1). Therefore, the synthesized nanocatalyst proved its good photocatalytic activity toward a cationic dye mixture of CV and MB dyes. Furthermore, this work confirms the potentiality of machine learning algorithms to develop predictive models for the elucidation of the degradation reaction pathway of organic dyes.

Development of a stability indicating high-performance liquid chromatography method for determination of cenobamate: study of basic degradation kinetics

This study presents a stability indicating high-performance liquid chromatography HPLC method for the determination of cenobamate (CNB) in presence of its main impurity (CNB H-impurity) and degradation products. The chromatographic separation was carried out on a Thermo BDS Hypersil-C18 column (150 × 4.6 mm; 5 μm) with a mobile phase consisting of a 50:50 (%v/v) ratio of methanol and purified water. The flow rate was maintained at 1.0 mL. min− 1. CNB was detected at 210 nm using a PDA detector. The column temperature was held at 40 °C.The retention time of the drug was found to be 3.2 min. Furthermore, the study investigates the degradation behavior of CNB under various stress conditions, including acidic, basic, oxidative, and light-induced degradation. The results indicate that CNB is particularly susceptible to basic degradation. Consequently, a comprehensive study of the basic degradation kinetics was conducted. The method was also successfully applied for the determination of CNB in its dosage form. The results also show that there is no co-elution from degradation products or excipients as indicated by the mass balance and peak purity values confirming the specificity of the proposed method and its applicability for routine analysis of CNB.

Synergistic detoxification efficiency and mechanism of triclocarban degradation by a bacterial consortium in the liver-gut-microbiota axis of zebrafish (Danio rerio)

Triclocarban (TCC), an emerging organic contaminant, poses a potential threat to human health with long-term exposure. Here, Rhodococcus rhodochrous BX2 and Pseudomonas sp. LY-1 were utilized to degrade TCC at environmental related concentrations for enhancing TCC biodegradation and investigating whether the toxicity of intermediate metabolites is lower than that of the parent compound. The results demonstrated that the bacterial consortium could degrade TCC by 82.0% within 7 days. The calculated 96 h LC50 for TCC, as well as its main degradation product 3,4-Dichloroaniline (DCA) were 0.134 mg/L and 1.318 mg/L respectively. Biodegradation also alleviated histopathological lesions induced by TCC in zebrafish liver and gut tissues. Liver transcriptome analysis revealed that biodegradation weakened differential expression of genes involved in disrupted immune regulation and lipid metabolism caused by TCC, verified through RT-qPCR analysis and measurement of related enzyme activities and protein contents. 16 S rRNA sequencing indicated that exposure to TCC led to gut microbial dysbiosis, which was efficiently improved through TCC biodegradation, resulting in decreased relative abundances of major pathogens. Overall, this study evaluated potential environmental risks associated with biodegradation of TCC and explored possible biodetoxification mechanisms, providing a theoretical foundation for efficient and harmless bioremediation of environmental pollutants.

Reverse Phase HPLC Methodology for the Determination of Bay K8644.

Following ICH guidelines for analytical validation, we report a common C18 column stability indicating isocratic reverse phase high performance liquid chromatography method for the determination of the ion channel modulator Bay K8644. Two main forced degradation products and a minor impurity were also tentatively identified by Mass Spectrometry. The mobile phase consisted of a 50/50 acetonitrile/buffer mixture at a flow rate of 2mL/min. Mean retention time for Bay K8644 was 3.030minutes. Excellent linearity (r = 0.9998) was achieved in the range 0.10-1.40μg/mL at 274nm wavelength. Analytical limits were 16.56 ± 1.04ng/mL for detection and 55.21 ± 3.48ng/mL for quantitation respectively. Accuracy and precision studies showed good results (95-105%). Robustness was assessed by varying ±3%, both temperature and flow rate. Five different stress conditions were applied to assess Bay K8644's stability. Only basic and photolytic treatments yielded degradation products, both correctly resolved in a total runtime of 4minutes. In conclusion, we developed a fast, simple, sensitive, accurate, precise, reliable and stability indicating method for detecting/quantifying Bay K8644, and tentatively characterized its main impurities/forced degradation products.

Development and Validation of an Analytical Method for the Determination of Fipronil and its Degradation Products in 28 Organic and Regular Honey Samples by GC-ECD

Recently, there has been a worldwide problem of increased bee mortality (Colony Collapse Disorder) and the intensive use of pesticides is suspected as one of the causes. Honey samples are one of many indicators to assess bee exposure to pesticides. In this work, a method for the simultaneous analysis of the pesticide Fipronil and its degradation products in honey samples by gas chromatography with electron capture detector (GC-ECD) is presented and validated. The extraction procedure was investigated using C18-SPE with different solvents and methanol showed the best performance. The analytical quantification was performed by internal standard matrix-matched calibration, which resulted in analytical curves presenting correlation coefficients higher than 0.99. The proposed method was validated with good results, such as recoveries around 70 - 99%, limits of detection and quantification bellow 0.014 and 0.072 μg mL-1, respectively, and relative standard deviations below 7%. The method is simple, effective and was successfully applied to 28 commercial honey samples, regular and organic, from different floral sources. The results showed the presence of fipronil desulfinyl, the main degradation product of fipronil, in some samples, even among the organic ones.

Studies on the Application of PGM Nanocatalysts from Spent Automotive Converters for Degradation of Ibuprofen in Aqueous Solutions.

There is an increasing concern about the presence of various types of pharmaceuticals in drinking water, as long-term exposure of people to even low concentrations of drugs can lead to many problems, such as endocrine disorders or drug resistance. As the removal in sewage treatment plants is not effective enough, as indicated, among others, by the EC and OECD reports, it is justified to search for new materials that will allow for an effective and rapid reduction of these pollutants in water. Therefore, in our work, catalytically active nanomaterials containing platinum group metals (PGMs) were synthesized from model and real multicomponent solutions and examined in reactions of organic compounds. The nanoparticles (NPs) were obtained from real solutions from the hydrometallurgical processing of spent automotive converters (SACs), and to the best of our knowledge, the novelty of the proposed paper is the application of solutions from SAC processing as precursors for PGM-NPs. The synthesized PGM-NPs were deposited on a support (TiO2), characterized and, finally, examined as nanocatalysts in a degradation reaction of ibuprofen (IB) from model aqueous solutions. The degree of IB degradation reached more than 90%. The main products of IB degradation were p-isobutylphenol and CO2.

Removal of enrofloxacin using Eichhornia crassipes in microcosm wetlands.

The global consumption of antibiotics leads to their possible occurrence in the environment. In this context, nature-based solutions (NBS) can be used to sustainably manage and restore natural and modified ecosystems. In this work, we studied the efficiency of the NBS free-water surface wetlands (FWSWs) using Eichhornia crassipes in microcosm for enrofloxacin removal. We also explored the behavior of enrofloxacin in the system, its accumulation and distribution in plant tissues, the detoxification mechanisms, and the possible effects on plant growth. Enrofloxacin was initially taken up by E. crassipes (first 100h). Notably, it accumulated in the sediment at the end of the experimental time. Removal rates above 94% were obtained in systems with sediment and sediment + E. crassipes. In addition, enrofloxacin was found in leaves, petioles, and roots (8.8-23.6µg, 11-78.3µg, and 10.2-70.7µg, respectively). Furthermore, enrofloxacin, the main degradation product (ciprofloxacin), and other degradation products were quantified in the tissues and chlorosis was observed on days 5 and 9. Finally, the degradation products of enrofloxacin were analyzed, and four possible metabolic pathways of enrofloxacin in E. crassipes were described.

Metabolism of novel potential syntrophic acetate-oxidizing bacteria in thermophilic methanogenic chemostats.

Acetate is a major intermediate in the anaerobic digestion of organic waste to produce CH4. In methanogenic systems, acetate degradation is carried out by either acetoclastic methanogenesis or syntrophic degradation by acetate oxidizers and hydrogenotrophic methanogens. Due to challenges in the isolation of syntrophic acetate-oxidizing bacteria (SAOB), the diversity and metabolism of SAOB and the mechanisms of their interactions with methanogenic partners are not fully characterized. In this study, the in situ activity and metabolic characteristics of potential SAOB and their interactions with methanogens were elucidated through metagenomics and metatranscriptomics. In addition to the reported SAOB classified in the genera Tepidanaerobacter, Desulfotomaculum, and Thermodesulfovibrio, we identified a number of potential SAOB that are affiliated with Clostridia, Thermoanaerobacteraceae, Anaerolineae, and Gemmatimonadetes. The potential SAOB possessing the glycine-mediated acetate oxidation pathway dominates SAOB communities. Moreover, formate appeared to be the main product of the acetate degradation by the most active potential SAOB. We identified the methanogen partner of these potential SAOB in the acetate-fed chemostat as Methanosarcina thermophila. The dominated potential SAOB in each chemostat had similar metabolic characteristics, even though they were in different fatty-acid-fed chemostats. These novel syntrophic lineages are prevalent and may play critical roles in thermophilic methanogenic reactors. This study expands our understanding of the phylogenetic diversity and in situ biological functions of uncultured syntrophic acetate degraders and presents novel insights into how they interact with methanogens.IMPORTANCECombining reactor operation with omics provides insights into novel uncultured syntrophic acetate degraders and how they perform in thermophilic anaerobic digesters. This improves our understanding of syntrophic acetate degradation and contributes to the background knowledge necessary to better control and optimize anaerobic digestion processes.

Enzymatic characterization and application of soybean hull peroxidase as an efficient and renewable biocatalyst for degradation of zearalenone

Zearalenone (ZEN) is a notorious mycotoxin commonly found in Fusarium-contaminated crops, which causes great loss in livestock farming and serious health problems to humans. In the present work, we found that crude peroxidase extraction from soybean hulls could use H2O2 as a co-substate to oxidize ZEN. Molecular docking and dynamic simulation also supported that ZEN could bind to the active site of soybean hull peroxidase (SHP). Subsequently, SHP extracted from soybean hulls was purified using a combined purification protocol involving ammonium sulfate precipitation, ion exchange chromatography and size exclusion chromatography. The purified SHP showed wide pH resistance and high thermal stability. This peroxidase could degrade 95 % of ZEN in buffer with stepwise addition of 100 μM H2O2 in 1 h. The two main ZEN degradation products were identified as 13-OH-ZEN and 13-OH-ZEN-quinone. Moreover, SHP-catalyzed ZEN degradation products displayed much less cytotoxicity to human liver cells than ZEN. The application of SHP in various food matrices obtained 54 % to 85 % ZEN degradation. The findings in this study will promote the utilization of SHP as a cheap and renewable biocatalyst for degrading ZEN in food.

Degradation kinetics of sugars (glucose and xylose), amino acids (proline and aspartic acid) and their binary mixtures in subcritical water: Effect of Maillard reaction

A systematic kinetic study was conducted in subcritical water medium in the temperature range from 150 to 200 °C for pure glucose, xylose, proline and aspartic acid as well as binary mixtures of sugars + amino acids to understand the reaction kinetics and interactions among biomass components and to discern the influence of Maillard reaction (MR) on the overall reaction kinetics.The main degradation products identified for glucose and xylose were the respective dehydration products, hydroxymethyl furfural and furfural, yielding an increasing solid residue with temperature (15.9 wt% at 200 °C) with an augmented heating value. The degradation of sugars and amino acids in binary systems was faster compared to pure compounds due to MR and the production of dehydration products was delayed when considering total sugar conversion. Higher relative reactivity in MR was observed for xylose over glucose showing also higher antioxidant activity.

Pyrite-activated persulfate to degrade 3,5,6-trichloro-2-pyridyl in water: Degradation and Fe release mechanism

TCP (3,5,6-trichloro-2-pyridinol), the main recalcitrant degradation product of chlorpyrifos, poses a high risk to human health and ecological systems. This study provided a comprehensive exploration of the pyrite-activated persulfate (PS) system for the removal of TCP in water and placed particular emphasis on the pyrite oxidation process that releases Fe. The results showed that the pyrite-activated PS system can completely degrade TCP within 300 min at 5.0 mmol/L PS and 1000 mg/L pyrite at 25 °C, wherein small amounts of PS (1 mmol/L) can effectively facilitate TCP removal and the oxidation of pyrite elements, while excessive PS (>20 mmol/L) can lead to competitive inhibitory effects, especially in the Fe release process. Aimed at the dual effects, the evident positive correlation (R2 > 0.90) between TCP degradation (kTCP) and Fe element release (kFe), but the value of k (0.00237) in the pyrite addition variable experiment was less than that in the PS experiment (k = 0.00729), further indicating that the inhibition effect of excessive addition consists of PS but not notably pyrite. Moreover, the predominant free radicals and non-free radicals produced in the pyrite/PS system were tested, with the order of significance being •OH < Fe (Ⅳ) < SO4•- < •O2− < 1O2, wherein 1O2 emerged as the principal player in both TCP degradation and Fe release from the pyrite oxidation process. Additionally, CO32− can finitely activate PS but generally slows TCP degradation and inhibit pyrite oxidation releasing Fe process. This study provides a theoretical basis for the degradation of TCP using pyrite-activated PS.

Synthesis of bio‐based poly(butylene carbonate‐co‐glycolic acid) with tunable degradation rate and mechanical properties

AbstractBio‐based copolymers with excellent mechanical properties and biodegradability are highly desired for packaging and agricultural applications. In this work, a series of high molecular weight bio‐based poly(ester‐carbonate)s are synthesized using glycolic acid (GA), dimethyl carbonate (DMC), and 1,4‐butanediol (BDO). The intrinsic viscosity ([η]) of these copolymers ranges from 0.70 to 1.11 dL/g. The tensile strength, elastic modulus, and elongation at break of PBCGA10 are 19.69 ± 2.40 MPa, 151.20 ± 37.17 MPa, and 1173 ± 142%, respectively, which are superior to the mechanical properties of PBAT. The degradation weight loss of PBCGA10 and PBCGA20 after 30 days can reach 8% and 40%, respectively, indicating excellent degradation performance of the copolymers. Moreover, copolymers undergo degradation through a surface degradation mechanism. The main products of copolymer degradation are BDO, CO2, and H2O, which do not cause harm to organisms and the environment.

Tolerability of silica microparticle gels as drug delivery vehicles

Aims/Purpose: Over the past decades, polymeric particles have become widespread in the field of drug delivery. Silica microparticles (SiMPs) are biodegradable—silicic acid being the main degradation product—and can release medication sustainably for a long period of time. Our aim was to determine the effects of soluble silicic acid on in vitro models of human epithelial cells.Methods: HCE‐2 and ARPE‐19 cells were exposed to serial dilutions of silicic acid produced by dissolving silica hydrogel in PBS, and cell viability was assessed after 24, 48 and 72 h of incubation. Cell viability data were provided by AlamarBlue assay, while membrane integrity was analysed through LDH release. For more information on the silicic acid impact on cellular stress, we assayed biochemical markers, such as IL‐6, IL‐8, MCP‐1, Caspase‐3 and Hsp‐70, using specific ELISAs.Results: AlamarBlue assay did not show any statistical differences in survival rate between the control group and maximum 30 μg/mL silicic acid in all timepoints in ARPE‐19 cells (24 h 95.42 ± 4.81%, 48 h 87.55 ± 6.48% and 72 h 97.64 ± 6.38%) and HCE‐2 cells (24 h 97.38 ± 5.97%, 48 h 100.81 ± 8.32% and 72 h 101.73 ± 2.62%). Additionally, we did not detect any toxic changes in LDH release test in ARPE‐19 cells in 24, 48 and 72 h time points (30 μg/mL silicic acid: 24 h 9.0 ± 11.5%, 48 h 10.4 ± 13.4% and 72 h 13.8 ± 16.6%). The LDH release data in treated (max. 30 μg/mL) HCE‐2 cells were comparable to control cells. Assessed inflammatory markers mostly were similar as well when comparing control and treatment groups, although IL‐6, MCP‐1, Caspase‐3 and Hsp‐70 showed increased values with time.Conclusions: Our results do not show major cytotoxicity of silicic acid on the two different epithelial cell lines, nor did not induce stress or inflammatory markers. Therefore, these findings support the use of our novel SiMPs as drug delivery vehicles in the treatment of ophthalmic diseases.

Sustainable fabrication of biogenic Fe–Zn nano core-shell and their photocatalytic efficiency against third generation antibiotics

The photocatalysis of third generation antibiotics was deliberated using biogenic iron oxide (FeO NPs) and iron-zinc (Fe–Zn) nano core-shell. Photocatalysts were prepared from aqueous extract of Adiantum incisum (Ai) by reacting with apposite salt solutions. FeO NPs were synthesized by mixing 5 % Ai extract with 5 mM FeSO4.7H2O at alkaline pH (50 °C). While Fe–Zn nano core-shell were synthesized by coating ZnO NPs on FeO NPs using successive reduction method. Synthesis and stabilization of nanoparticles were substantiated by diverse surface plasmonic resonance peak of FeO NPs and Fe–Zn nano core-shell at explicit wavelength ranges. Band gap energy values, Thermogravimetric analysis (TGA), X-Ray Diffraction (XRD), Raman and Scanning Electron Microscope (SEM) analysis validates that coating was done efficaciously. Fourier Transform Infrared Spectroscopy (FTIR) recognized the role of plant phytochemicals in NPs reduction and stabilization. SEM-Energy Dispersive X-Ray analysis (EDX) analysis unveiled that FeO NPs and core-shell aggregates are orbicular in shape. Average crystalline size of FeO NPs and Fe–Zn nano core-shell obtained from XRD was 15.64 nm and 22.94 nm respectively. The photocatalytic degradation of Ampicillin, Levofloxacin and Ceftriaxone under UV and Sunlight displayed that Fe–Zn nano core-shell have high degradation capability than FeO NPs. Degradation potential was higher in UV than in sunlight. Maximum degradation of Ampicillin (74.4 %) was attained under UV light and (60.31 %) in sunlight followed by Levofloxacin. Degradation was further confirmed by conducting FTIR analysis and antimicrobial studies. Gas Chromatography-Mass Spectrometry detected Hexadecenoic acid as the main degradation product in nano treated Ampicillin and Levofloxacin.

Assessing the effect of organic amendments on the degradation of profoxydim in paddy soils: Kinetic modeling and identification of degradation products

The fate and behavior of herbicides can be altered in an unpredictable way when organic amendments are added to soil as a beneficial management tool. The objective of this work was to investigate the effect exerted by the addition of two different organic amendments (alperujo compost and biochar) to soil in the degradation of one of the most relevant new generation rice herbicides, profoxydim. In unamended soils, the degradation of profoxydim was quite fast and was governed by both chemical (DT50steril soil = from 1.52 to 9.21 days) and microbial (DT50nonsterile soil = from 0.47 to 0.53 days) processes.Alperujo- and biochar-amended soils significantly increased the persistence of the herbicide in both soils, especially in the presence of biochar, due to the high capacity absorption of this amendment, increasing DT90 from 1.92 to 3.54 days for DT90unamended to 41.02–48.41 days for DT90biochar amended. Different kinetics models applied to fit the observed dissipation datasets showed that a HS biphasic model fits well with the dissipation of profoxydim in amended and unamended soils.For the first time, five degradation products (DPs) were identified by HPLC-QTOF-MS/MS in soil and a degradation pathway was described. Main DP was generated via oxidation of the sulfur atom to give rise to the corresponding sulfoxide derivative, with this DP being more persistent than the active substance.These outcomes can be very useful for the assessment of the environmental risk associated with the use of profoxydim in rice crops and the application of organic amendments as potential measures for minimizing the risk of contamination of natural water resources.

Size exclusion chromatography as green support for forced degradation study of adalimumab.

Size exclusion chromatography (SEC) has become a powerful tool for analysing size variants of biologic drugs in their native form. Modern SEC can be defined by the use of chromatographic columns packed with sub-3 µm particles, allowing an increase in method throughput compared to that of conventional SEC. We performed the forced degradation study of adalimumab, the first genetically engineered fully humanised immunoglobulin G1 monoclonal antibody, and evaluated tha possibilities of an advanced SEC column packed with sub-3 µm particles for elucidation of the degradation pathway. Our results revealed the main adalimumab degradation products to be antibody fragments. Acidic and basic conditions had the most intensive effect on the degradation of the adalimumab while the drug exhibits relative stability under thermal and photolytic stress conditions. The AGREE and AGREEprep calculators were used for the evaluation of the environmental performance of the forced degradation procedure. The results of the green score evaluation are presented as round pictograms with a circle in the centre that shows the overall score of 0.81 and 0.61, respectively. Both pictograms are highlighted in green, indicating the eco-friendly conditions.

Degradation of roxarsone and simultaneous immobilization of inorganic arsenic by L-cys modified FeMnNi-LDH activated persulfate system

A series of novel L-cysteine (L-cys) modified iron-manganic-nickel hydrotalcite (L-cys-LDH) were synthesized and used for heterogeneous catalytic activation of monopersulfate (PMS) to degrade roxarsone (ROX) and adsorption of released inorganic arsenic. The catalyst was characterized by TEM, XRD, FTIR, XPS, and other characterization techniques to analyze its structure and functional properties. The degradation experiment results showed that the activity of the catalyst was effectively improved after L-cys loading on LDH. In the pH range of 3–9, 0.2 g/L L-cys-LDH and 0.2 mM PMS could degrade more than 90 % of ROX in 20 min, three times higher than that of ordinary FeMnNi-LDH. Besides, the residual amount of inorganic arsenic in the solution was less than 0.01 mg/L. The electron paramagnetic resonance (EPR) test and quenching investigation identified surface-bound SO4-· and surface-bound ·OH as the main contributors to organic degradation. Mechanism studies have shown that cysteine embedded in LDH accelerated the conversion rate of Fe(III)/Mn(III) to Fe(II)/Mn(II) by self-oxidation to cystine, thereby improving the efficiency of catalyst activation of PMS. In addition, the main degradation products were obtained by LC-MS analysis, and the possible pathway of ROX degradation was given in L-cys-LDH/PMS system combined with DFT theoretical calculation. The work showed that L-cys-LDH exhibited excellent catalytic performance and inorganic arsenic adsorption capacity. It provides an idea for the improvement of hydrotalcite-based catalysts. It also sheds some light on the degrade of novel hydrotalcite-based catalysts for the one step degradation and adsorption of ROX.

Synergistic effect and removal mechanism of trichloroethylene (TCE) by nano scale zero-valent iron (nZVI) supported on biological calcium carbonate (CaCO3)

Microbial induced calcium carbonate precipitation (MICP) is a green and environmentally friendly technology. Herein, porous biological CaCO3 was prepared by MICP technology and then used as the carrier material for nZVI to prepare CaCO3@nZVI composite. Afterwards, the various properties of the CaCO3@nZVI composite were methodically characterized. Subsequently, the adsorption kinetic equation and adsorption isotherm model of TCE were carefully investigated, and the CaCO3@nZVI composite dosage, initial pH, temperature, aging time and the number of cycles on the TCE removal efficiency were examined. Finally, the degradation mechanism of TCE by CaCO3@nZVI composite was revealed. The results showed that nZVI particles were successfully supported on the biological CaCO3 surface, and the specific surface area of the CaCO3@nZVI composite was 52.641 m2/g, which was much higher than that of bare nZVI (8.757 m2/g). The adsorption kinetics of CaCO3@nZVI composite for TCE removal was conformed to the pseudo-second-order kinetic equation, and Freundlich model was more appropriate as the adsorption isotherm model. The optimal conditions for the TCE removal were obtained to be 0.24 g/L CaCO3@nZVI composite dosage, 25 ℃, and initial pH of 7.0, respectively. Furthermore, the CaCO3@nZVI composite exhibited good stability and reusability. The main degradation products of TCE by CaCO3@nZVI composite were acetylene, ethylene, and ethane, and the synergistic effects of adsorption and degradation were the main mechanisms of TCE removal. Generally, this paper provides experimental support for the selection of nZVI carrier materials, which is useful for promoting the development and advancement of green repair materials.