Amine Research Articles

Direct Electron Transfer-Driven Nontoxic Oligomeric Deposition of Sulfonamide Antibiotics onto Carbon Materials for In Situ Water Remediation.

The rising in situ chemical oxidation (ISCO) technologies based on polymerization reactions have advanced the removal of emerging contaminants in the aquatic environment. However, despite their promise, uncertainties persist regarding their effectiveness in eliminating structurally complex contaminants, such as sulfonamide antibiotics (SAs). This study elucidated that oligomerization, rather than mineralization, predominantly governs the removal of SAs in the carbon materials/periodate system. The amine groups in SAs played a crucial role in forming organic radicals and subsequent coupling reactions due to their high f- index and low bond orders. Moreover, the study highlighted the robust adhesion of oligomers to the catalyst surface, facilitated by enhanced van der Waals forces and hydrophobic interactions. Importantly, plant and animal toxicity assessments confirmed the nontoxic nature of oligomers deposited on the carbon material surface, affirming the efficacy of carbon material-based ISCO in treating contaminated surface water and groundwater. Additionally, a novel classification approach, Δlog k, was proposed to differentiate SAs based on their kinetic control steps, providing deeper insights into the quantitative structure-activity relationship (QSAR) and facilitating the selection of optimal descriptors during the oligomerization processes. Overall, these insights significantly enhance our understanding of SAs removal via oligomerization and demonstrate the superiority of C-ISCO based on polymerization in water decontamination.

A simple and effective method for smartphone-based detection of polyamines in oral cancer

Oral cancer accounts for 50%–70% of all cancer-related deaths in India and ranks sixth among the most frequent cancers globally. Roughly 90% of oral malignancies are histologically arise from squamous cells and are therefore called oral squamous cell carcinoma. Organic polycations known as biogenic polyamines, for example, putrescine (Put), spermidine (Spd), and spermine (Spm), are vital for cell proliferation, including gene expression control, regulation of endonuclease-mediated fragmentation of DNA, and DNA damage inhibition. Higher Spm and Spd levels have been identified as cancer biomarkers for detecting tumour development in various cancers. The current study utilises tannic acid, a polyphenolic compound, as a reducing and capping agent to fabricate AuNPs via a one-step microwave-assisted synthesis. The fabricated TA@AuNPs were utilised as a nanoprobe for colourimetric sensing of polyamines in PBS. When TA@AuNPs are added to the polyamine, the amine groups in polyamines interact with the phenolic groups of TA@AuNPs via hydrogen bonding or electrostatic interactions. These interactions cause the aggregation of TA@AuNPs, resulting in a red shift of the Surface Plasmon Resonance band of TA@AuNPs from 530 nm to 560 nm. The nanoprobe was found to be highly specific for Spm at low concentrations. TA@AuNPs were able to detect Spm successfully in artificial saliva samples. On recording the RGB values of the sensing process using a smartphone app, it was found that as the nanoparticles aggregated due to the presence of Spm, the intensity of the R-value decreased, indicating the aggregation of TA@AuNPs due to interaction with the polyamine.

Low-temperature plasma-treated polyethylene oxide for hemostasis and skin wound healing

The development of a hemostatic material capable of controlling substantial blood loss in wound healing scenarios remains a critical challenge in clinical practice. Herein, we treated polyethylene oxide (PEO) with low-temperature plasma irradiation (LTPI) technology in the air, and the modified PEO (CAPEO) was obtained with carboxyl (–COOH) and amine (–NH2) groups. Notably, CAPEO exhibited excellent hydrophilicity, great cytocompatibility, and blood compatibility. Platelets could be activated more and clotting time could be shorter with the treatment of CAPEO than with PEO. More importantly, in the rat liver hemorrhage model, the blood loss in CAPEO (95.8 mg) was less than in PEO (144.2 mg). Moreover, in vivo investigation of skin wound repair, CAPEO could promote epidermal regeneration and collagen deposition, thereby accelerating wound healing. These findings disclose that CAPEO holds great potential for hemostasis and wound healing.

Enhancement of Tricyclazole Analysis Efficiency in Rice Samples Using an Improved QuEChERS and Its Application in Residue: A Study from Unmanned Arial Spraying

Enhancements to the analytical method for the determination of tricyclazole in rice samples have been applied to monitor residues during unmanned aerial spraying. The acetonitrile extraction technique QuEChERS was improved by the incorporation of ethyl acetate and 0.1% formic acid, which significantly elevated the recovery rates. Furthermore, the purification process was refined by integrating both primary–secondary amine (PSA) and C18 in the dSPE method, achieving a substantial improvement in reducing matrix effects (MEs) and increasing recovery efficiency. The optimized method demonstrated an impressive % ME value at −3.1%, with a limit of quantitation (LOQ) established at 0.01 mg/kg, and recovery rates between 94.7 and 95.6% at 0.01, 0.1, and 2 mg/kg. Using two types of adjuvants (stickers) during multi-copter spraying markedly improved the initial tricyclazole deposition on rice panicles, with residue levels initially increasing from 0.35 mg/kg to between 0.68 and 1.60 mg/kg. Residues in hulled rice at harvest (10 days post-application) remained well below the maximum residue limit (MRL) of 0.7 mg/kg, ranging from 0.02 to 0.11 mg/kg, thus affirming the safety and efficacy of adjuvants in residue management.

Self-Neutralizing Melamine-Urea-Formaldehyde-Citric Acid Resins for Wood Panel Adhesives.

In this study, we used a self-neutralizing system to counteract too acidic a pH, unsuitable for wood adhesives, and tested it on MUF resins augmented by the addition of citric acid or other organic acids, based on the addition of small percentages of hexamine or another suitable organic base to form an acid-base buffer. In this manner, the pH of the adhesive was maintained above the minimum allowed value of 4, and the strength results of wood particleboard and plywood bonded with this adhesive system increased due to the additional cross-linking imparted by the citric acid. Thus, the wood constituents at the wood/adhesive interface were not damaged/degraded by too low a pH, thus avoiding longer-term service failure of the bonded joints. The addition of the buffering system increased the strength of the bondline in both the plywood and particleboard, both when dry and after hot water and boiling water tests. The IB strength of the particleboard was then increased by 15-17% when dry but by 82% after boiling. For the plywood, the shear strengths when dry and after 3 h in hot water at 63 °C were, respectively, 37% and 90% higher than for the control. The improvement in the bonded panel strength is ascribed to multiple reasons: (i) the slower, more regular cross-linking rate due to the action of the buffer; (ii) the shift in the polycondensation-degradation equilibrium to the left induced by the higher pH and the long-term stability of the organic buffer; (iii) the additional cross-linking by citric acid of some of the MUF resin amine groups; (iv) the already known direct linking of citric acid with the carbohydrates and lignin constituents at the interface of the wood substrate; and (v) the likely covalent linking to the interfacial wood constituents of the prelinked MUF-citric acid resin by some of the unreacted citric acid carboxyl groups.

Advanced properties of gold nanoparticles obtained by using long-chain secondary amine for phase transfer from water to chloroform

We have conducted a new comparison of gold nanoparticles functionalized by primary- and secondary amine with the same chain length. Our hypothesis suggests that the adaptive steric conformation of the secondary amine molecular branches makes a marked additional contribution to the well-established role of the ligand chain length. We characterize the importance of this factor based on diOctadecylamine (diODA) and Octadecylamine (ODA) passivated gold nanoparticles by using high-resolution transmission electron microscopy (HR-TEM) and selective area electron diffraction (SAED). The results evidenced that the diODA coordination to the inorganic core forms a more efficient and impenetrable protective coating. The SAED patterns show a more homogeneous distribution of the small crystalline domains in the gold core. TEM images show a smooth spherical shape of the diODA nanoparticles and a lack of interparticle coalescence cases. The diODA-passivation provides nanoparticles with nearly twice the effective ligand length than its ODA equivalent. This results in their spontaneous arrangement in domains with expressed crystal-like order despite the relatively large size-dispersity before passivation. The surface free energy of coatings, formed by diODA passivated gold nanoparticles, is twice as small as measured on the ODA-nanoparticle-coated surfaces.

Silver@copper-polyaniline nanotubes: Synthesis, characterization and biosensor analytical study

We introduce silver-copper nanoparticles incorporated into polyaniline (PANI) nanotubes using a straightforward and efficient reduction process. In this regard, PANI nanotubes with amine groups were fabricated through oxidation polymerization, followed by the attachment of Ag and Cu precursors to enable the synthesis of Ag-Cu bimetallic nanoparticles (NPs) on the pre-formed PANI nanotubes with the use of hydrazine as a reducing agent. The structural characterization of the synthesized NPs was investigated by UV–Vis spectrophotometer (UV–Vis), Dark-field emission, (EDX), X-ray diffraction (XRD) and field emission (FESEM), while the electrochemical properties were estimated by (CV) and differential pulse voltammetry (DPV). The findings indicated that the Ag-Cu NPs were present in the nanoscale range, well-dispersed, and attached to the surface of PANI nanotubes. Electrochemical investigations revealed that the Ag-Cu@PANI nanotube electrode demonstrated efficient electrooxidation of dopamine and hydroquinone without any interfering reactions, suggesting its potential use as an electrochemical biosensor for simultaneous detection of dopamine and hydroquinone. The proposed NPs-based biosensor was connected to concurrently identify dopamine and hydroquinone, illustrating moo distinguish Confinements of 0.46 µM for dopamine and 0.23 mM for hydroquinone, separately. Additionally, the manufactured sensor identified on a wide direct run the dopamine (5–25 µM), and hydroquinone (0.5–2.5 mM). Alongside these promising comes about, the Ag-Cu@PANI nanotube actualized great solidness and reproducibility, making it a favorable stage for electrochemical biosensing of dopamine and hydroquinone.

Improving the removal rate of bisphenol A and Cu2+ from water using P/N coexisting β-cyclodextrin-based adsorbents by enhancing adsorbents-pollutants interactions

Bisphenol A (BPA), a prominent endocrine-disrupting compound, has garnered considerable attention due to its urgent need for rapid removal from water. Herein, we first used a novel reactive phosphine oxide containing tertiary amines as crosslinker to prepare water-insoluble crosslinked β-cyclodextrin (β-CD) adsorbent via radical-mediated thiol–ene polymerization. Owing to the synergistic hydrogen-bond (H-bond) interactions of functional groups (tertiary amine and PO groups) toward BPA, the resulted adsorbents showed fast adsorption kinetics to BPA with an adsorption equilibrium time of 5 min. After six adsorption–desorption cycles, the removal efficiency of BPA was 92.5 %, indicating its excellent reusability. Due to the presence of the CS bonds, the β-CD -derived bio-adsorbents offered binding sites for Cu2+ ions, resulting in a maximum adsorption capacity of 113.89 mg g−1.

Effects of surface wettability and density change during solidification of paraffin phase change materials

Phase change materials (PCMs) are widely used for thermal energy storage and other applications. During the solidification of a PCM, a volume change occurs due to thermal expansion and structural change of the molecules. A concave shape may be created during the solidification shrinkage. This paper investigates the shrinkage profile formed during the solidification of paraffin wax and its relationship with the surface wettability (contact angle), considering the effect of density changes. The contact angle of a paraffin droplet on a surface indicates the extent of adhesion between the solid surface and paraffin. The experimental study examines a mixture of wax with nanoparticles, wax with surfactants, different coatings on the container surface, and different solidification temperatures. Enhanced adhesion and increased shrinkage height are observed due to the non-polar interaction between coated surfaces and paraffin, facilitated by induced dipole-induced dipole forces. The addition of 3% octadecylamine enhances adhesion between paraffin and the container, as driven by dipole–dipole forces between the hydroxyl group on epoxy resin-container surfaces and the hydrophilic amine group of octadecylamine. The shrinkage height increases with a decrease in the contact angle of paraffin on the surface. The shrinkage profile also changes with the solidification temperature. The highest shrinkage profile is achieved for the highest solidification temperature.

L-cysteine modified N-doped carbon quantum dots derived from peach palm (Bactris gasipaes) peels for detection of mercury ions

Establishing an effective strategy for Hg2+ determination with good sensitivity and high selectivity is of particular concern. In this work, N-doped carbon quantum dots (NCQDs) were obtained for the first time from peels of peach palm fruit (Bactris gasipaes) through microwave-assisted one-pot synthesis. Surface NCQDs was modified with l-cysteine (NCQDs/CYS) by a chemical reaction (known as amide coupling) between the nitrogen-containing groups (amine group) of l-cysteine ligand and the carboxyl groups of NCQDs. The chemical bonding was examined by Fourier Transform Infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). NCQDs/CYS nanoparticles exhibited a quantum yield of fluorescence (ΦFL) of 25.4%, high solubility in water, and a surface with thiol groups from l-cysteine. Mercury ions induced quenching of fluorescence of NCQDs/CYS at low concentrations (Limit of Detection, LOD = 0.19 μM) with great sensitivity. A significant preference for Hg2+ ions was found because of the high affinity between the thiolate groups of NCQDs/CYS and the analyte. Time-resolved fluorescence measurements were done to study the way that led to fluorescence quenching when Hg2+ ions were present, evidencing a static quenching fluorescence mechanism. The new NCQDs/CYS material could be applied to accurately measure the concentration of Hg2+ ions in water samples in a fast and cost-effective way.

The modified pomegranate peel as an economical and highly effective adsorbent for malachite green dye removal from wastewater

This research investigated the ability of acid-modified pomegranate peel to remove malachite green (MG) dye from aqueous solutions. Pomegranate peel, an abundant agricultural byproduct, was modified using hydrochloric acid to enhance its adsorption capacity. The effects of parameters like particle size, pH, initial MG concentration, contact time, temperature and adsorbent dosage on the dye removal efficiency were studied. Under optimized conditions of pH 8, 40 min contact time, 25°C temperature and 0.01 g/ml adsorbent dose with 5 mg/L MG solution, about 96.8 % dye removal was achieved. Kinetic data fitted well to the pseudo-second order model, indicating chemisorption with electrostatic interactions governing the adsorption. Equilibrium data were best described by the Temkin isotherm model, suggesting a heterogeneous binding energy distribution. Thermodynamic calculations revealed the exothermic and spontaneous nature of MG adsorption. FTIR analysis confirmed introduction of functional groups like carboxyl, amine and alkyl groups on the adsorbent surface after acid modification, enabling interactions with dye cations. SEM images displayed increased surface roughness and porosity for the modified biosorbent relative to the raw form. The acid-modified pomegranate peel proved to be an economical, eco-friendly and effective adsorbent for removing the hazardous cationic dye MG from wastewater. The findings support agricultural waste valorization for environmental remediation applications.

Effect of lubricant functional groups on tribological properties of epoxy/graphene composites

AbstractThe functional group in the molecular chain of lubricants is a key factor for a boundary lubricating film, which can further enhance the friction performance by interfacial tribochemistry. In this paper, the tribological behavior of epoxy/graphene (EP/Gra) composites was investigated through varying lubrication conditions, including dry friction, or different lubricants (such as water, hexadecane, oleylamine, and oleic acid). The porosity and Shore hardness (SHD) of the EP composites were significantly improved by the addition of graphene. Results showed that the porosity of the EP/0.75 wt.% Gra composites was reduced by 75.6% and their SHD increased by 5.4 compared with the EP/0.05 wt.% Gra composites. The average coefficient of friction (COF) of the composites was reduced by at least 27.3% under dry friction conditions. For water as lubricant, the EP/0.5 wt.% Gra composite exhibited the lowest COF (0.0455). The EP/0.75 wt.% Gra composite displayed the lowest COF (0.0466) when hexadecane acted as lubricant. By contrast, EP/0.05 wt.% Gra showed the lowest COF (0.0389) with oleylamine as lubricant, and the EP/0.25 wt.% Gra composites gave the lowest COF (0.0433) under oleic acid. The amine group of oleylamine reacted with the EP group to form a hydroxyl group, resulting in a polymer with low friction adhered to the friction interface. Simultaneously, the EP group reacted with the carboxyl group, forming a network of hydrogen bonds with graphene, which reduced the shear stress on the friction interface. Therefore, the functional groups of lubricants have a vital influence on the tribological properties of frictional composites, which may provide a new approach to solving the problem of wear.

Cross-linking of mesoporous bioactive glass nanoparticle incorporated gelatin hydrogels by tannic acid with enhanced mechanical performance and stability

Gelatin-based hydrogels are used in diverse biomedical applications, such as wound dressings, tissue regeneration, and cell culture models. However, gelatin requires additional cross-linking to form a stable hydrogel. Tannic acid (TA), a polyphenolic compound, can undergo the Michael addition reaction and Schiff's base reaction with primary amine groups in neutral aqueous solutions. In this work, TA was selected as a cross-linker of gelatin to fabricate hydrogels reacting with primary amine groups in the gelatin molecular chain. Primary amine-modified mesoporous bioactive glass nanoparticles (AMBGNs) were added to further enhance the cross-linking of the system. The swelling ratios and weight losses showed that the most stable hydrogels retain approximately 53 % of their mass after 28 days of immersion in PBS solution. Young's modulus increased significantly with the increase in the content of TA and AMBGNs. The addition of TA and AMBGNs also resulted in a substantial reduction of gelation time. The prepared hydrogels possessed adequate stability and mechanical properties and showed potential for customized application in a variety of clinical service settings, such as wound healing, bone regeneration, and soft tissue regeneration.

Copper-Based Bio-MOF/GO with Lewis Basic Sites for CO2 Fixation into Cyclic Carbonates and C-C Bond-Forming Reactions.

Several measures, including crude oil recovery improvement and carbon dioxide (CO2) conversion into valuable chemicals, have been considered to decrease the greenhouse effect and ensure a sustainable low-carbon future. The Knoevenagel condensation and CO2 fixation have been introduced as two principal solutions to these challenges. In the present study for the first time, bio-metal-organic frameworks (MOF)(Cu)/graphene oxide (GO) nanocomposites have been used as catalytic agents for these two reactions. In view of the attendance of amine groups, biological MOFs with NH2 functional groups as Lewis base sites protruding on the channels' internal surface were used. The bio-MOF(Cu)/20%GO performs efficaciously in CO2 fixation, leading to more than 99.9% conversion with TON = 525 via a solvent-free reaction under a 1 bar CO2 atmosphere. It has been shown that these frameworks are highly catalytic due to the Lewis basic sites, i.e., NH2, pyrimidine, and C═O groups. Besides, the Lewis base active sites exert synergistic effects and render bio-MOF(Cu)/10%GO nanostructures as highly efficient catalysts, significantly accelerating Knoevenagel condensation reactions of aldehydes and malononitrile as substrates, thanks to the high TOF (1327 h-1) and acceptable reusability. Bio-MOFs can be stabilized in reactions using GO with oxygen-containing functional groups that contribute as efficient substitutes, leading to an expeditious reaction speed and facilitating substrate absorption.

Gold nanoclusters cure implant infections by targeting biofilm

The biofilm-mediated implant infections pose a huge threat to human health. It is urgent to explore strategies to reverse this situation. Herein, we design 3-amino-1,2,4-triazole-5-thiol (ATT)-modified gold nanoclusters (AGNCs) to realize biofilm-targeting and near-infrared (NIR)-II light-responsive antibiofilm therapy. The AGNCs can interact with the bacterial extracellular DNA through the formation of hydrogen bonds between the amine groups on the ATT and the hydroxyl groups on the DNA. The AGNCs show photothermal properties even at a low power density (0.5 W/cm2) for a short-time (5 min) irradiation, making them highly effective in eradicating the biofilm with a dispersion rate up to 90 %. In vivo infected catheter implantation model demonstrates an exceptional high ability of the AGNCs to eradicate approximately 90 % of the bacteria encased within the biofilms. Moreover, the AGNCs show no detectable toxicity or systemic effects in mice. Our study suggests the great potential of the AGNCs for long-term prevention and elimination of the biofilm-mediated infections.

Discovery of Novel (+)-Nootkatone-Based Amine Derivatives as Potential Insecticide Candidates.

To discover novel natural product-based insecticides, a series of (+)-nootkatone-based amine derivatives 3a-t were prepared and evaluated for their insecticidal activities against Mythimna separata Walker, Myzus persicae Sulzer, and Plutella xylostella Linnaeus. Insecticidal assays showed that most of the title (+)-nootkatone derivatives exhibited stronger insecticidal activities against three insect pests than the precursor (+)-nootkatone after the introduction of amine groups on the parent (+)-nootkatone. Compounds 3a, 3d, 3h, 3m, 3n, 3p, and 3r displayed more promising growth inhibitory (GI) effect against M. separata than the commercially available botanical insecticide toosendanin. Compound 3o exhibited the most potent aphicidal activity with an LD50 value of 0.011 μg/larvae, which was 2.09-fold higher than the positive control rotenone. Additionally, compounds 3g and 3n showed more promising larvicidal activity against P. xylostella with LC50 values of 260 and 230 mg/L, respectively, superior to that of rotenone (460 mg/L). Moreover, derivatives 3g and 3n exhibited better control efficacy toward P. xylostella than rotenone under greenhouse conditions. Preliminary mechanistic studies revealed that derivative 3n could inhibit the activity of glutathione S-transferase (GST) in P. xylostella and thus exerted larvicidal activity, and molecular docking further demonstrated that 3n could interact well with some amino acid residues of GST. Finally, the toxicity assay suggested that derivatives 3g and 3n were relatively less toxic to nontarget organisms. These findings will provide insights into the development of (+)-nootkatone derivatives as green pesticides.

Antimicrobial properties of hindered amine light stabilizers in polymer coating materials and their mechanism of action.

UV-stabilizers are a class of additives that provide extended polymer resistance to UV-degradation, but have also been suggested to have antimicrobial activity, potentially preventing the spread of pathogens, and inhibiting microbial-induced biodegradation. In this work, we incorporated different UV-stabilizers, a hindered amine light stabilizer (HALS), Tinuvin 770 DF and Tinuvin PA 123, or a hybrid HALS/UV-absorber, Tinuvin 5151, in polyurethane formulations to produce lacquer-films, and tested their antimicrobial activity against Staphylococcus aureus (methicillin-resistant and -sensitive strains), Escherichia coli and Candida albicans. Lacquer-films incorporated with Tinuvin 770 DF showed strong antimicrobial performance against bacteria and fungi, while maintaining cytocompatibility. The mechanism of action revealed a positive relationship between Tinuvin 770 DF concentration, microbial death, and reactive nitrogen species (RNS), suggesting that RNS produced during autoxidation of Tinuvin 770 DF is responsible for the antimicrobial properties of this UV-stabilizer. Conversely, lacquer-films incorporated with Tinuvin 5151 or Tinuvin PA 123 exhibited no antimicrobial properties. Collectively, these results highlight the commercial potential of Tinuvin 770 DF to prevent photo- and biodegradation of polymers, while also inhibiting the spread of potentially harmful pathogens. Furthermore, we provide a better understanding of the mechanism underlying the biocidal activity of HALS associated to autooxidation of the amine group.

Chitosan Properties: A Preliminary Review

The content of amino groups in chitosan becomes the main cause of its differences from chitin in the context of structures and properties such as their chelation, flocculation, and biological functions. Furthermore, the random distribution of chitosan makes it easier to generate intra-and inter-molecular hydrogen bonds. Also, the existence of two hydroxyl groups and one primary amine group in chitosan, which can donate a free pair of electrons, make it soluble in diluted aqueous acetic solvents, and allow the formation of the coordination bonds that increase the possibilities for chemical modification. Its modification includes the incorporation of hydrophobic groups. Therefore, this paper reviews the properties of chitosan.

Removal of ionic and colloidal 110 mAg from radioactive wastewater using radiografted chelating adsorbents

This research investigates the performance of new radiografted materials as adsorbents for ionic and colloidal 110 mAg, a prominent pollutant in pressurized water reactor (PWR) wastewater. A comparative analysis was conducted to evaluate their effectiveness against commercially available resins. Due to the increasing demand for new nuclear power plants and the growing global dependence on nuclear energy, it is crucial to minimize radioactive waste production. The study was conducted on simulated inactive and radioactive waste samples with trace amounts of 110 mAg that are hard or impossible to detect by standard analytic techniques. The synthesized materials were labeled PGE (amine functional groups) and PGM (sulfhydryl and amine functional groups). Functionalization with amine and sulfhydryl groups was chosen since it is well known that these groups strongly interact with Ag in both ionic and colloidal form. The tested materials demonstrate exceptional performance as adsorbents by completely removing (100 %) both ionic (PGM) and colloidal (PGE) forms of 110 mAg. Additionally, depending on the adsorbed species excellent elution of 110 mAg was achieved (>94 % for ions and >50 % for colloids) implying possible material reusability. Manufacturing cost of such adsorbents is orders of magnitude lower per kg (10 – 50 $/kg), compared to prices of commercial resins (100 – 10000 $/kg). These results indicate that such inexpensive materials could potentially be used in an efficient and selective way to treat PWR wastewater for 110 mAg contamination while reducing the operating cost and minimizing resulting solid waste.

Mass Spectrometry Imaging of Coniine and Other Hemlock Alkaloids after On-Tissue Derivatization Reveals Distinct Alkaloid Distributions in the Plant.

Specialized metabolites play important roles in plants and can, for example, protect plants from predators or pathogens. Alkaloids, due to their pronounced biological activity on higher animals, are one of the most intriguing groups of specialized metabolites, and many of them are known as plant defense compounds. Poison hemlock, Conium maculatum, is well-known for its high content of piperidine alkaloids, of which coniine is the most famous. The distribution, localization, and diversity of these compounds in C. maculatum tissues have not yet been studied in detail. The hemlock alkaloids are low molecular weight compounds with relatively high volatility. They are thus difficult to analyze on-tissue by MALDI mass spectrometry imaging due to delocalization, which occurs even when using an atmospheric pressure ion source. In this manuscript, we describe an on-tissue derivatization method that allows the subsequent determination of the spatial distribution of hemlock alkaloids in different plant tissues by mass spectrometry imaging. Coniferyl aldehyde was found to be a suitable reagent for derivatization of the secondary amine alkaloids. The imaging analysis revealed that even chemically closely related hemlock alkaloids are discretely distributed in different plant tissues. Additionally, we detected a yet undescribed hemlock alkaloid in Conium maculatum seeds.