Quaternary Ammonium Research Articles

Trypsin Digestion Conditions of Human Plasma for Observation of Peptides and Proteins from Tandem Mass Spectrometry.

Previous meta-analysis indicated that plasma or serum proteome groups using various experimental conditions detected different peptides from the same plasma proteins, which is strong evidence for the veracity of blood fluid LC-ESI-MS/MS but also evidences that the trypsin digestion step is a key source of variation in plasma proteomics. Agreement between different digestion conditions and MS/MS algorithms may serve as an independent confirmation of the validity of the LC-ESI-MS/MS analysis of plasma peptides. Plasma contains a high percentage of albumin held together by multiple disulfide bonds; hence, reduction and/or alkylation may greatly enhance the digestion efficiency of albumin. Plasma proteins were precipitated in 90% acetonitrile, collected over quaternary amine resin, and eluted in NaCl prior to digestion treatments. To determine the effect of trypsin digestion methods, the plasma proteins were digested in 600 mM urea and 5% acetonitrile with trypsin alone, or reduced with 2 mM DTT followed by trypsin, or DTT followed by 15 mM iodoacetamide and then trypsin. The resulting peptides were analyzed by LC-ESI-MS/MS with a linear quadrupole ion trap (LIT). The MS/MS spectra were directly fit to peptides by the X!TANDEM and SEQUEST algorithms. Blank noise injections served as the analytical control, and 30 million random MS/MS served as the statistical control. Digesting human plasma with DTT reduction, or reduction and alkylation, resulted in a dramatic increase in the number and observation frequency of albumin peptides. In contrast, digestion with trypsin alone suppressed the observation of albumin, and instead, many low abundance plasma and cellular proteins showed higher observation frequency. Digestion with trypsin alone increased the observation frequency of APOC1, ACAN, ATRN, CPB2, GP2, GPX3, HBA1, PAPD5, PKD1, and many cellular proteins. After correction against noise and random controls, SEQUEST showed good agreement with the true positive plasma proteins identified by X!TANDEM and resulted in an R-squared of 0.5238 with an F-statistic of 10,930 on 9,935 protein gene symbols with a p-value < 2.2e-16. Digestion of plasma with trypsin alone avoids the complete digestion of albumin and permits the enhanced detection of some other cellular proteins from plasma. Different digestion approaches were complimentary and together resulted in a more comprehensive plasma proteome. The protein FDR q-values, the modest effect of background and Monte Carlo correction, and the significant STRING analysis were all consistent with the high fidelity of the rigorous X!TANDEM algorithm. In contrast, SEQUEST required significant correction against noise and statistical controls and selection of high cross correlation (XCorr) scores to show good agreement with X!TANDEM. There was qualitative and quantitative agreement between plasma proteins digested without alkylation from the orbital ion trap (OIT) versus the LIT instrument that showed highly significant regression against the X!TANDEM OIT monoisotopic results, those from heavy isotopes and other masses from X!TANDEM, and with those from MaxQuant. There was significant qualitative and quantitative agreement between the complementary digestion conditions consistent with the good fidelity of plasma analysis by LC-ESI-MS/MS with a sensitive linear ion trap.

Photo-crosslinking injectable Photothermal antibacterial hydrogel based on quaternary ammonium grafted chitosan and hyaluronic acid for infected wound healing

Antibacterial hydrogels not only provide a better environment for skin wounds to avoid infection but also accelerate wound healing. Herein, chitosan modified by a quaternary ammonium salt (CQ), and hyaluronic acid grafted with methacrylate (HM) were designed and synthesized to prepare an injectable photo-crosslinking hydrogel for wound dressing with inherent antibacterial and photothermal properties. CQ and HM exhibited excellent biocompatibility, improved water retention, and antibacterial activity, illustrating vast potential as an antibacterial material in various applications. MXene, a type of 2D nanomaterial, has been widely researched due to its photothermal properties. The CQ and HM polymer precursor could be mixed with Mxene and then crosslinked with 395 nm UV radiation under mild conditions to form a 3D network structure CQ-HM/MXene hydrogel. This hydrogel displayed an appropriate swelling ratio, elastic modulus, photothermal property and excellent biocompatibility. The injectable property of the hydrogel allowed it to easily cover the wound. In vitro and in vivo studies showed that the injectable hydrogel had low cytotoxicity and excellent antibacterial properties, which could help promote wound healing. In summary, this novel CQ-HA/MXene hydrogel has the potential for application in skin wound healing due to inherent antibacterial activity and photothermal effect.

Henkel‐like Decarboxylation Produces Mononuclear Arylalkalis, [4‐(CH3)3N(C6H4)M]+ which Hydrolyse and Undergo Surprising SN2 Reactions Between Alkali Hydroxides and (CH3)3NC6H5+

AbstractBenzoate substituted with a cationic quaternary ammonium group at the para‐position, [4‐(CH3)3N(C6H4)CO2], forms mononuclear alkali metal ion complexes, [4‐(CH3)3N(C6H4)CO2M]+ (M=Li, Na, K, Rb and Cs), which are observed by electrospray‐ionisation mass spectrometry. When mass selected and subjected to collision‐induced dissociation each of these complexes undergoes decarboxylation to produce the mononuclear arylalkali complex cations, [4‐(CH3)3N(C6H4)M]+, which subsequently react with water via hydrolysis to yield the quaternary ammonium cation, (CH3)3NC6H5+. The unexpected product ions, [M((CH3)2NC6H5)]+, [M(CH3OH)]+, and M+, which are associated with the hydrolysis pathway, suggest an unusual reaction occurring within the exit channel ion‐molecule complex, [(CH3)3NC6H5+MOH]+. DFT calculations were used to examine the: decarboxylation reaction of [4‐(CH3)3N(C6H4)CO2M]+, which readily proceeds via a four‐centred transition state; the hydrolysis and SN2 reactions accounting for formation of products in the exit channel, which are connected via a roaming mechanism in which the metal hydroxide moiety migrates from the para‐hydrogen of (CH3)3NC6H5+ to one of the methyl groups.

Dialdehyde cellulose nanofibrils/polyquaternium stabilized ultra-fine silver nanoparticles for synergistic antibacterial therapy

Dialdehyde cellulose nanofibrils (DACNF) and Polyquaternium-10 (PQ: chloro-2-hydroxy-3-(trimethylamino) propyl polyethylene glycol cellulose) have become increasingly favored as antibacterial substances due to their advantageous characteristics. DACNF exhibits exceptional mechanical properties and biocompatibility, whereas PQ demonstrates a positive charge that enhances its antibacterial activity. Combined in a DACNF/PQ mixture, they provide an excellent template material for preparing and stabilizing ultra-fine (~ 10.3 nm) silver nanoparticles (AgNPs) at room temperature. Here, the dialdehyde group of DACNF functions as a reducing agent, while the quaternary ammonium of PQ and carboxylate groups of DACNF synergistically helped in-situ generation of AgNPs uniformly. The synthesized nanocomposites, namely PQ@AgNPs, AgNPs@DACNF, and AgNPs@DACNF/PQ, were subjected to comprehensive characterization using various advanced analytical techniques. The films containing AgNPs@DACNF and AgNPs@DACNF/PQ, fabricated via vacuum filtration, exhibited excellent mechanical properties of 9.78 ± 0.21 MPa, and demonstrated superior antibacterial activity against both Escherichia coli and Staphylococcus aureus. Additionally, the silver ion leaching from the prepared composite films was well controlled. The fabricated nanocomposites also effectively inhibited bacterial biofilm formation. It was also found to be highly biocompatible and non-toxic to human skin fibroblast cells. Furthermore, the nanocomposites exhibited enhanced migration of human dermal fibroblasts, suggesting their potential in facilitating wound healing processes.

Mass loading, removal and emission of 27 quaternary ammonium compounds, including metabolites of benzalkonium, in a wastewater treatment plant in New York state, USA

Benzylalkyldimethylammonium (BACs), dialkyldimethylammonium (DDACs), and alkyltrimethylammonium compounds (ATMACs) are quaternary ammonium compounds (QACs) widely used in industrial and consumer products. Nevertheless, little is known about their fates in wastewater treatment plants (WWTPs). We detected 7 BACs, 6 DDACs, 6 ATMACs, and 8 hydroxy- and carboxyl- metabolites of BACs (BACm) in wastewater collected from a WWTP in New York State. The median concentrations of ∑All (sum concentration of all 27 analytes) in influent and final effluent were 31900 and 545 ng/L, respectively, which corresponded to a removal efficiency of 98 %. C14-BAC, C10-DDAC, C18-DDAC, and C16-ATMAC were the major compounds found in influent (collectively accounting for 62 % of ∑All), suggestive of their prevalent usage in consumer products. BACm were detected for the first time in wastewater (median: 1720 ng/L in influent), and they comprised 8–11 % of ∑All in wastewater, which highlighted the importance of monitoring QAC metabolites in wastewater. The mass loadings of QACs into the WWTP were in the range of 1480–10700 mg/d/1000 inhabitants, whereas the corresponding emission rates were in the range of 119–7720 mg/d/1000 inhabitants. QACs present in final effluents may exert low to moderate risks on aquatic organisms, which warrants more attention.

Exploring the reaction mechanistic pathway for the sensing of G-Series nerve agent with Kemp's triacid derivative: A computational study

Kemp's triacid derivative have been reported as a candidate for sensing of nerve agents employing the photoinduced electron transfer (PET) processes. The sensor probe molecules were prepared with primary alcohol in very close proximity to a tertiary amine to acylate the alcohol with rapid intramolecular N-alkylation to produce quaternary ammonium salt. The reaction pathways for the formation of quaternary ammonium salt and isomethyl propyl phosphonate remain unexplored. In this report, the mechanistic pathways of G-series nerve agents sarin and its simulant diethylcholorophosphate (DCP) with Kemp's triacid derivatives has been explored computationally. The calculations performed with B3LYP-D3/6-311+G(d,p) level of theory in DCM solvent revealed that the reaction proceeds via intermolecular and intramolecular SN2 pathways. The probe molecule is sterically hindered, therefore, the frontside and backside SN2 reaction pathways have been examined. The computed results suggest that the first intermolecular SN2 reaction of Kemp's triacid derivatives (I &II) with sarin for the backside attack is energetically favored compared to the frontside attack and the following intramolecular SN2 reaction is a barrierless process. The calculations performed with simulant diethylcholorophosphate (DCP) and Kemp's triacid derivatives (I &II) show that the reactions are energetically more facile compared to the nerve agent sarin molecule. The Distortion-Interaction model and ΔNBOSteric analysis showed that the back side is energetically favored over the front side attack in such SN2 reactions. The designed Kemp's triacid derivative (II) with phosphorus center for sensing sarin and (DCP) suggests that the size of the hetero centers are important to facilitate the reaction in the probe molecule.

Physysichemical Properties of Quaternary Ammonium Salts Formed by Undecanoic and Tetradecanoic Acids with Trietanolamine

Abstract The article presents the results of the study of the oil collecting and oil dispersing properties of the quaternary ammonium salts formed by undecanoic and tetradecanoic acids, which are monobasic carboxylic acids, with triethanolamine (TEA) in distilled, drinking, and sea waters contaminated with Balakhani Oil. The surface activity property of the products of different concentrations of these complexes was calculated using a tensiometer, and the elemental composition was calculated using the calculation method. A comparative study of the element composition of the salts of both acids formed with TEA shows that the mass fraction of carbon in the complex formed by tetradecanoic acid with TEA is higher than in the other complex. Comparison of the surface activity property of the complexes formed by undecane and tetradecanoic acid with TEA shows that the complex compound formed by tetradecanoic acid with TEA shows more surface activity property. Therefore, as the mass fraction of carbon element increases in the complexes formed by undecane and tetradecanoic acid with TEA, the complex compound shows more surface activity properties.

Filovirus outbreak responses and occupational health effects of chlorine spraying in healthcare workers: a systematic review and meta-analysis of alternative disinfectants and application methods.

In the context of filovirus outbreaks, chlorine spraying has been the standard for infection prevention and control. Due to potential occupational health risks, public health institutions now recommend wiping, which is labor-intensive and may increase the risk of heat stress for healthcare workers wearing personal protective equipment. This systematic review and meta-analysis quantified the health effects of occupational exposure to chlorine-based products compared to other disinfectants, and the effects of spraying compared to general disinfection tasks (GDTs) like wiping and mopping, in healthcare settings. MEDLINE, Scopus, and ScienceDirect were searched for studies addressing the association between exposure to disinfectants applied by different application methods and occupational diseases in healthcare settings. Risk of bias was assessed by two independent reviewers using a validated tool. Two reviewers independently screened and performed data extraction and synthesis. A third reviewer resolved disagreements. Meta-analyses were conducted using fixed- and random-effects models based on the Higgins I2 statistic. 30 studies investigating chlorine-based products (7,123 participants), glutaraldehyde (6,256 participants), peracetic acid, acetic acid and hydrogen peroxide (4,728 participants), quaternary ammonium compounds (QACs) (9,270 participants), use of spray (4,568 participants) and GDTs (3,480 participants) were included. Most had a cross-sectional design and high risk of bias. Meta-analysis indicates a significant association between respiratory conditions and exposure to chlorine-based products (OR 1.71, 95%CI 1.41-2.08), glutaraldehyde (OR 1.44, 95%CI 1.14-1.81), QACs (OR 1.30, 95%CI 1.06-1.60), use of spray (OR 2.25, 95%CI 1.61-3.14) and GDTs (OR 2.20, 95%CI 1.66-2.90). The relative odds ratio (ROR) of respiratory conditions for chlorine-based products compared to QACs was 0.76 (95%CI 0.62-0.94). The ROR for the use of spray compared to GDTs was 0.98 (95%CI 0.74-1.29). Strengths include evaluating respiratory health risks of disinfectants, applying a validated tool, using both fixed- and random-effects models, and comparing pooled effect sizes. Limitations include high risk of bias for the majority of included articles, varying confounder adjustments, underreported non-respiratory outcomes, and unspecified disinfectants and PPE use for spray and GDTs articles. Chlorine-based disinfectants significantly increase respiratory risk compared to QACs. Sprays and general disinfection tasks present similar risks. Our findings advocate for using less hazardous products like QACs, rather than banning sprays in filovirus outbreak responses to enhance disinfection safety. CRD42023479363.

Lysine and valine weaken antibiotic resistance in Salmonella Typhimurium induced by disinfectant stress

Disinfectants are widely used in food production and environmental sanitation to prevent illness, but bacteria resistance to these disinfectants and co-resistance to antibiotics pose a threat to public health. This study investigated the impact of commonly used disinfectants on the resistance of Salmonella Typhimurium (ST) to disinfectants and antibiotics, and explored the metabolic mechanisms underlying the resistance changes. The results showed that subinhibitory concentrations of disinfectants had a minor impact on the resistance of ST to four disinfectants. However, chlorine-containing disinfectants stress enhanced bacteria resistance to ampicillin, while quaternary ammonium compounds stress increased resistance to tetracycline and gentamicin. Untargeted metabolomics analysis revealed significant changes in glutathione metabolism and lysine and valine degradation pathways after disinfectant exposure. Specifically, ST activated lysine decarboxylation, leading to a significant decrease in lysine levels after benzalkonium chloride exposure, while valine and leucine degradation pathways were activated by sodium hypochlorite stress. The addition of downregulated L-lysine and L-valine increased the sensitivity of ST to antibiotics, providing further evidence for the findings of metabolomics. This study provides guidance for the proper use of disinfectants in food processing and establishes a strategy based on metabolomics to control antibiotic-resistant bacteria.

Study on the synthesis of nanosheets petal-shaped ZSM-5 Zeolites

In this work, a novel strategy for hydrothermal synthesis of nanosheets petal-shaped ZSM-5 zeolites was introduced. The experimental results indicated that the nanosheets petal-shaped ZSM-5 zeolites exhibited a higher specific surface area and more abundant acid sites. Under the synergistic crystallization effect of ethanol and seeds, the addition of CTAB promoted the growth of the layered structure, and the introduction of trace amounts of seeds effectively inhibited the growth of mordenite in a high alkalinity environment, reducing the crystallization time to 48 hours. More importantly, the petal-shaped ZSM-5 zeolites exhibited excellent MTP (Methanol-to-Propylene) catalytic performance, with methanol conversion maintained above 97.8 % for 80 hours and a maximum propylene selectivity of 49.1 %. This paper proposes an Ethanol-Seed-CTAB synthesis method for producing petal-shaped ZSM-5 zeolite with a unique morphology. This approach does not require the use of complex gemini quaternary ammonium surfactants in the synthesis process, greatly promoting the application and dissemination of nanosheets zeolites.

Development of a QuEChERS-based method for the determination of quaternary ammonium compounds in different food matrices by LC-MS/MS

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) - based method was developed and validated for the determination of six benzalkonium chloride (BAC) homologues (C8-C18) and four didecyldimethylammonium chloride (DDAC) homologues (C8-C14) in various food commodities. Quaternary ammonium compounds (QACs) are cationic surfactants and biocides commonly found in cleaning and disinfecting products widely used in industrial applications, households, agriculture, hospitals, and healthcare facilities and their usage has increased since the COVID-19 pandemic. The method was validated in terms of specificity, selectivity, linearity, limit of quantification (LOQ), accuracy (recovery percentage), precision (CV %) and matrix effect (ME %). %). Intraday and interday precision were evaluated at two levels. Mean recoveries for all matrices fell within 70–120 %, with CV% below 20 %. All calibration curves demonstrated excellent linearity (R² ≥ 0.998). The LOQ was set and verified at 0.01 mg/kg for each analyte. The results were satisfactory according to the SANTE/2021/11312 guidelines. In addition, the method included the elimination of water at each stage of sample preparation and throughout the chromatographic system to minimize background noise. The method was successfully applied to analyse 46 samples of animal origin. BAC C14 was the most frequently detected compound (76 % of the samples) and in two samples, the sum of BACs was above the MRL set by EU the Regulation. These findings, coupled with limited data on QAC levels in meat and seafood products, underscore the necessity for further investigation into these matrices.

Berberine Targets PKM2 to Activate the t-PA-Induced Fibrinolytic System and Improves Thrombosis.

Arterial thrombosis, a condition in which thrombi form in arteries, can lead to various acute cardiovascular diseases and impact the quality of life and survival of patients. Berberine (BBR), a quaternary ammonium alkaloid, has been shown to treat these diseases. However, further exploration is needed to understand underlying mechanisms of BBR. Rats were administered BBR via intramuscular injection. Then, an FeCl3-coated filter paper was applied to a carotid artery to induce thrombosis. The size of the thrombus and the blood flow velocity were evaluated by carotid ultrasound. The shape of the thrombus was observed using staining and microscopy. The expression levels of mRNA and proteins were verified. Additionally, mass spectrometry and single-cell RNA sequencing analysis were conducted. The administration of BBR resulted in a significant reduction in the thrombus area and an extension of the thrombus-clogging time. Furthermore, BBR administration effectively reversed the decreasing tissue-plasminogen activator (t-PA) expression and alterations in fibrinolysis system of model group. Additionally, the expression of PKM2 was suppressed following BBR administration, and the overexpression of PKM2 inhibited t-PA expression. BBR ameliorates thrombosis by modulating expression of PKM2, subsequently impacting the expression of t-PA within fibrinolytic system. These preliminary findings suggest that BBR could be a potential preventive and therapeutic strategy for arterial thromboembolic diseases.

Dimerization of perfluoropropyl vinyl ether during the pyrolysis of hexafluoropropylene oxide dimer

Dimerization of perfluoropropyl vinyl ether (PPVE) generally reduces its yield and selectivity during the pyrolysis of hexafluoropropylene oxide dimer ((HFPO)2). However, the mechanism of PPVE dimerization is not well understood. In this paper, the PPVE dimer was obtained during the pyrolysis of (HFPO)2. Subsequently, the chemical structure of PPVE dimer was further determined by gas chromatography-mass spectrometry (GC–MS) and nuclear magnetic resonance (NMR). The results showed that the concentration of PPVE dimer rises in proportion to the extended reflux time of PPVE in the reaction system. Based on the experimental phenomenon, a possible generation mechanism of PPVE dimer was then proposed, and the possibility of the generation pathway was further verified in combination with density functional theory (DFT). In addition, to effectively reduce the production of PPVE dimer, crown ethers and quaternary ammonium salts were added to the reaction system as phase transfer catalysts. Among them, the phase transfer catalyst (15-crown-5) was more effective and reduced the PPVE dimer content from 1.34 % to 0.31 %. This work provides an idea to inhibit the dimerization of PPVE and increase the yield and selectivity of PPVE.

The use of in vitro bioassays and chemical screening to assess the impact of a minimally processed vegetable facility on wastewater quality.

Fruit- and vegetable-processing facilities may contaminate wastewater via contaminants found in the produce and disinfecting chemicals used. These contaminants may include agrochemicals, pesticides, and disinfectants such as chlorine and quaternary ammonium compounds (QACs). Some compounds may exhibit harmful endocrine-disrupting activity. This study investigated the impact of a minimally processed vegetable facility on wastewater quality via in vitro bioassays and chemical screening. Estrogen activity was assessed via a yeast estrogen screen (YES), and (anti-)androgenic and glucocorticoid activities were evaluated via an MDA-kb2 reporter gene assay. The samples were screened via gas and liquid chromatography-tandem mass spectrometry (GC-MS/MS and LC-MS/MS) to identify target compounds, and GC coupled with time-of-flight mass spectrometry (GC-TOFMS) was used for non-targeted screening. Sample complexity and chemical profiles were assessed using GC-TOFMS. Estrogenic activity was detected in 16 samples (n = 24) with an upper limit of 595 ± 37ng/L estradiol equivalents (EEqs). The final wastewater before discharge had an EEq of 0.23ng/L, which is within the ecological effect-based trigger value range for the estrogenic activity of wastewater (0.2-0.4ng/L EEq). Androgenic activity was detected in one sample with a dihydrotestosterone equivalent (DHTEq) value of 10 ± 2.7ng/L. No antiandrogenic activity was detected. The GC-MS/MS and LC-MS/MS results indicated the presence of multiple pesticides, nonylphenols, triclocarban, and triclosan. Many of these compounds exhibit estrogenic activity, which may explain the positive YES assay findings. These findings showed that wastewater from the facility contained detergents, disinfectants, and pesticides and displayed hormonal activity. Food-processing facilities release large volumes of wastewater, which may affect the quality of the water eventually being discharged into the environment. We recommend expanding conventional water quality monitoring efforts to include additional factors like endocrine activity and disinfectant byproducts.

Systematic Study on Swelling/Delamination of Layered Metal Oxides with Quaternary Ammonium Ions: Production of Well-Shaped/Oversized Unilamellar Nanosheets.

Enormous swelling of layered host compounds in an aqueous solution of various amines has been investigated as an important step in the synthesis of molecularly thin 2D nanosheets. However, a complete understanding of the reaction process has not been attained, which is the barrier for producing high-quality unilamellar nanosheets. Here, the swelling and delamination behaviors of platelet single crystals of protonated layered metal oxides are systematically examined with a series of tetraalkylammonium (TAA) hydroxide solutions. Upon contact with the solutions, the crystals immediately underwent massive expansion by several tens to hundreds of times. The swollen crystals can be delaminated into elementary layers by the application of external shear force. The exfoliation behavior is dependent on TAA ions, especially in terms of yield and lateral size/shape of the delaminated nanosheets. The swollen crystals with TAA ions with longer alkyl chains are delaminated almost completely, but irregular and fractured small sheets are yielded. Such long alkyl chains become entangled on the oxide layer and resulting hydrophobic interactions may be responsible for the lateral fragmentation. It is found that replacement of aqueous solutions with organic solvents to suppress the hydrophobic interactions is effective to produce oversized nanosheets in rectangular shape with sharp edges.

Adaptations to cationic biocide exposure differentially influence virulence factors and pathogenicity in Pseudomonas aeruginosa

ABSTRACT Cationic biocides (CBs), which include quaternary ammonium compounds (QACs), are employed to mitigate the spread of infectious bacteria, but resistance to such surface disinfectants is rising. CB exposure can have profound phenotypic implications that extend beyond allowing microorganisms to persist on surfaces. Pseudomonas aeruginosa is a deadly bacterial pathogen that is intrinsically tolerant to a wide variety of antimicrobials and is commonly spread in healthcare settings. In this study, we pursued resistance selection assays to the QAC benzalkonium chloride and quaternary phosphonium compound P6P–10,10 to assess the phenotypic effects of CB exposure in P. aeruginosa PAO1 and four genetically diverse, drug-resistant clinical isolates. In particular, we sought to examine how CB exposure affects defensive strategies and the virulence-associated “offensive” strategies in P. aeruginosa. We demonstrated that development of resistance to BAC is associated with increased production of virulence-associated pigments and alginate as well as pellicle formation. In an in vivo infection model, CB-resistant PAO1 exhibited a decreased level of virulence compared to wild type, potentially due to an observed fitness cost in these strains. Taken together, these results illustrate the significant consequence CB resistance exerts on the virulence-associated phenotypes of P. aeruginosa.

The effect of alkyl chain on the corrosion inhibition of benzyldimethylammonium chloride in acidic environments

Incorporating quaternary ammonium salts (QAS) during pickling is an efficient and eco-friendly approach to mitigating metal corrosion. This study investigated the effectiveness of Benzyldimethylhexadecylammonium chloride (HDBAC) and Benzyldimethyltetradecylammonium chloride (TDBAC) in inhibiting the corrosion of Q235 steel in H2SO4, utilizing electrochemical methods, atomic force microscopy (AFM), scanning electron microscopy (SEM), and theoretical calculations. The electrochemical results demonstrated that compared with the blank impedance value of 40.68Ω cm2, HDBAC and TDBAC at 5 mM concentration showed impedance values of 997.69Ω cm2 and 676.17 Ω cm2 at 298 K, indicating that they can effectively prevent the corrosion of Q235. SEM and AFM further showed the formation of a protective barrier film by HDBAC and TDBAC on the steel surface, effectively isolating it from the corrosive medium. Theoretical calculations further elucidated the mechanism by which these inhibitors create this protective barrier. The experiment also verified the hypothesis that the length of the hydrophobic chain of surfactants affects the adsorption behavior and the inhibition efficiency. When comparing their inhibitory effects at 5 mM concentrations, HDBAC exhibited superior performance (95.92 %) against Q235 in 0.5 M H2SO4, compared to TDBAC (94.09 %). These findings provide valuable insights for developing more effective and sustainable corrosion inhibitors for industrial applications.

High-throughput screening of green amino acid and surfactant mixtures with high corrosion inhibition efficiency: Experimental and modelling perspectives

A high-throughput screening method is developed for rapid evaluation of corrosion inhibitors. By employing a fluorometric technique, this method quickly assesses the concentration of iron ions converted from corrosion products in the reaction pool to rapidly evaluate the corrosion inhibition performance of amino acid and surfactants. Utilizing this high-throughput screening platform, the corrosion inhibition effects of L-cysteine mixed with quaternary ammonium salts of different alkyl chain length were evaluated, and their optimal mixing ratios were determined. Through corrosion experiments and molecular simulations, the synergistic mechanisms of the inhibitor mixtures are revealed.

PPS-reinforced poly(terphenylene) anion-exchange membranes with different quaternary ammonium groups for use in water electrolysers

The nature, concentration and spatial distribution of quaternary ammonium (QA) groups is instrumental for the performance of anion exchange membranes, primarily by augmenting the ion exchange capacity (IEC). This study compares a series of poly(meta-terphenylene)-based ion exchange membranes (mTPN), which vary in the attached quaternary ammonium group. The IEC of the membranes is 1.97, 2.20 and 3.70 mmol OH− g−1 for membranes functionalized with 1,4-diazabicyclo[2.2.2]octane (DABCO), trimethylamine (TMA), and methylated DABCO (DABCO-Me), respectively. The latter is obtained by methylation of the DABCO-functionalized membrane.To control swelling, all membranes are reinforced with a poly(phenylene sulfide) (PPS) fiber mat. The highest conductivity, achieved by PPS/mTPN/DABCO-Me, is 140 mS cm−1 in 1 M KOH and 237 mS cm−1 in 4 M KOH. An alkaline stability test over 2 months revealed that membranes with TMA and DABCO have a stable in-plane conductivity, measured in pure water, while the membrane with DABCO-Me showed a strongly increased resistance. On the other hand, a 1 month stability test showed that the through-plane conductivity of the membrane with DABCO-Me in 1 M KOH hardly changed. This indicates that conductivity by absorbed KOH solution is more relevant than the conductivity provided by the quaternary ammonium groups, and promises stable operation in the electrolyser. This is supported by an electrolyser test, where a stable voltage of 1.9 V at 0.25 A cm−2 was achieved, with no observed change in membrane resistance over a test duration of 100 h (60 °C, 4 M KOH, PGM-free catalyst).

Determination of dimethyl sulfate genotoxic impurity in pantoprazole sodium sesquihydrate by derivatization method and UPLC/MS

In this study, a new method has been developed and, the method has been validated to analyze dimethyl sulfate (DMS) which known as a genotoxic impurity. DMS has been detected in trace levels within the drug substance pantoprazole sodium sesquihydrate using the derivatization method. Triethylamine has been used as derivatization reagent. Due to the highly polar nature of the derivatization product, which is a quaternary ammonium ion, a polar retention Hilic column has been used for chromatographic separation. The Waters QDA detector has been used in the single ion recording (SIR) mode at m/z 116 for the detection of the quaternary ammonium ion. In this study, the recovery rates have been achieved within the range of 96.46–105.98%. The LOD has been determined as 1.94E-07 mg/mL, and the LOQ has been determined as 6.46E-07 mg/mL. From the results, it can be said that the improved method in this study, would enables fast and reliable solutions for routine quality control analyses for DMS in API companies that especially is producing PSS.