Didecyldimethylammonium Research Articles

Seed germination responses of broomrape species (Phelipanche ramosa and Phelipanche aegyptiaca) to various sanitation chemicals

AbstractBranched broomrape, an obligate root parasitic weed, has recently re-emerged in tomato fields in several California counties. California produces more tomato than any other state, and the outbreak of this noxious weed could potentially wreak havoc on the industry’s economy. Preventive measures must be taken to stop or reduce the spread of branched broomrape seeds to other areas. Branched broomrape can produce thousands of tiny seeds, which can easily spread with farm machinery over short and long distances. To prevent branched broomrape seed dispersal, sanitation and disinfection of farm equipment are necessary before entering a new farm. We tested the effectiveness of various ammonium compounds, including didecyl dimethyl ammonium chloride (DDAC), alkyl dimethyl benzyl ammonium chloride (ADBC), didecyl dimethyl ammonium bromide (DDAB), ammonium bromide (AB), and ammonium chloride (AC) on prevention of branched broomrape seed germination. Dose-response analysis showed that three chemical products, ADBC, DDAB, and DDAC, could completely inhibit branched broomrape seeds (potentially making them nonviable) at 1%, 1%, and 10% wt/vol concentrations, respectively. These three compounds were further tested in an exposure duration experiment that additionally included Egyptian broomrape. Only 10 min of exposure to these compounds was needed to prevent germination of both branched and Egyptian broomrape seeds at 1% (ADBC, DDAB) and 10% wt/vol (DDAC). Lower concentrations can provide similar inhibition effects when combined with longer exposure times. Egyptian broomrape seeds were more sensitive than branched broomrape seeds. Findings suggest that quaternary ammonium compounds could be used as potential sanitation agents to disinfect agriculture machinery from branched and Egyptian broomrape seeds.

Efektivitas Didecyldimethylammonium Chloride 2.5% dan Chlorine 0.5% terhadap Pertumbuhan Staphylococcus aureus dan Klebsiella pneumoniae di Ruang Operasi

This study aims to determine the effectiveness of the disinfection of 0.5% chlorine and 2.5% didecyldimethylammonium chloride against Staphylococcus aureus and Klebsiella pneumoniae in the operating room. The method used is a quasi-experimental post-only group design with a total sample of 40 samples of the operating room environment. The results showed no difference between the two types of disinfectants, namely didecyldimethylammonium chloride 2.5% and chlorine 0.5% in reducing the number of bacteria (p-value 0.373) and both were able to reduce the number of Staphylococcus aureus and Klebsiella pneumoniae. In conclusion, both disinfectants effectively reduced Staphylococcus aureus and Klebsiella pneumoniae on operating room surfaces.
 Keywords: Didecyldimethylammonium Chloride Disinfection, Chlorine, Bacterial Growth, Operating Room

Didecyldimethylammonium Chloride- and Polyhexamethylene Guanidine-Resistant Bacteria Isolated from Fecal Sludge and Their Potential Use in Biological Products for the Detoxification of Biocide-Contaminated Wastewater Prior to Conventional Biological Treatment.

Simple SummaryEvery year, more than a million tons of fecal sludge (FS) containing biocides based on quaternary ammonium compounds and guanidine derivatives, which are widely used for FS deodorization and control of microbial activity, are generated in the environmentally safe toilet complexes of Russian Railways trains. Higher disposal costs for such biocide-contaminated FS due to activated sludge toxicity increases pressure on sanitary equipment servicing companies («Ecotol Service» LLC) to more efficiently discharge FS to wastewater treatment plants. In this work, we have developed a new environmentally friendly approach to reducing the toxicity of FS, based on the use of biological products from biocide-resistant bacterial strains isolated from FS. Our approach has proven to be effective in a series of FS biodegradation experiments, biological oxygen demand tests, and a newly developed disk-diffusion bioassay.Toxic shock caused by the discharge of biocide-contaminated fecal sludge (FS) from chemical toilets to conventional wastewater treatment plants (WWTP) can be a major problem in activated sludge operation. It is necessary to develop new environmental approaches to mitigate the toxicity of biocides in order to avoid degrading the performance of WWTP. “Latrina”, a chemical toilet additive containing didecyldimethylammonium chloride and polyhexamethylene guanidine, is widely used in environmentally safe toilet complexes (ESTC) on Russian railway trains to deodorize FS and control microbial activity. In this work, seven biocide-resistant bacterial strains were isolated and identified from the FS of ESTC. The values of the minimum inhibitory and bactericidal concentrations of biocides for the isolated strains were 4.5–10 times higher than for the collection microorganisms. The bacterium Alcaligenes faecalis DOS7 was found to be particularly resistant to “Latrina”, the minimum inhibitory concentration of which was almost 30 times higher than recommended for ESTC. Biological products based on isolated bacterial strains proved to be effective for FS biodegradation under both aerobic and anaerobic conditions. The results of the biochemical oxygen demand test and the newly developed disk-diffusion bioassay confirmed that isolated strains contribute to reducing toxicity of biocidal agents in FS. Hyper-resistance, non-pathogenicity, and potential plant growth-promoting ability make A. faecalis DOS7 promising for use in various biological products for wastewater treatment and bioremediation of soils contaminated with biocides, as well as in agriculture to increase plant productivity.

Reducing the biogenic corrosion of concrete in a pigsty by using disinfectants

The object of this study is the regularity of changes in the biogenic destructive effect of microorganisms on the concrete structural elements of livestock facilities due to the use of the original liquid phase mixture of disinfectant based on aldehyde and surfactant. Microorganisms use construction materials as a substrate for growth and nutrition; they produce citric acid, which leads to a change in the composition and morphology of hydrated cement new formations. The composition of the microflora of the pigsty has been determined, and the minimum concentration of disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride was found. By the TPD MS method, a decrease in the intensity of carbon dioxide (CO2) release in concrete samples during the heating of the sample to 900 °C was proved, compared to the control intact corrosion sample. Electron microscopy of concrete samples shows the presence of destructive changes and colonies of micromycetes. It was established that calcite was intensively released in the control sample of concrete, which retained its integrity and was not subjected to corrosion when heated to a temperature of 600 °C. Electron microscopy confirms the preservation of the homogeneous structure of concrete. The use of a disinfectant based on glutaraldehyde and didecyl dimethyl ammonium chloride at a concentration of 1 % destroys colonies of micromycetes, 2 % – the shell of microorganisms, and 3 % – biofilm. Treatment of concrete with a disinfectant at a concentration of 3 % destroys microorganisms Aspergillus fumigatus and Penicillium oxalicum, inhibits the process of biological corrosion of concrete, and strengthens the structure of concrete. The results of the experiment can be applied to inhibit the corrosion of concrete and extend the life of building structures made of concrete through the use of a disinfectant based on aldehyde and didecyl dimethyl ammonium chloride at a concentration of 3 %.

Biocides used as material preservatives modify rates of de novo mutation and horizontal gene transfer in bacteria

Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution and transmission of AMR. Previous studies showed that de-novo mutagenesis and horizontal gene transfer (HGT) by conjugation or transformation – important processes underlying resistance evolution and spread - are affected by antibiotics, metals and pesticides. However, natural microbial communities are also frequently exposed to biocides used as material preservatives, but it is unknown if these substances induce mutagenesis and HGT. Here, we show that active substances used in material preservatives can increase rates of mutation and conjugation in a species- and substance-dependent manner, while rates of transformation are not increased. The bisbiguanide chlorhexidine digluconate, the quaternary ammonium compound didecyldimethylammonium chloride, the metal copper, the pyrethroid-insecticide permethrin, and the azole-fungicide propiconazole increase mutation rates in Escherichia coli, whereas no increases were identified for Bacillus subtilis and Acinetobacter baylyi. Benzalkonium chloride, chlorhexidine and permethrin increased conjugation in E. coli. Moreover, our results show a connection between the RpoS-mediated general stress and the RecA-linked SOS response with increased rates of mutation and conjugation, but not for all biocides. Taken together, our data show the importance of assessing the contribution of material preservatives on AMR evolution and spread.

Effect of the medium composition on the extraction of chromium, aluminium and iron hydroxides from wastewater by electroflotation

The process of electroflotation is used for treatment of wastewaters carrying heavy and non-ferrous metals in the form of poorly soluble compounds if the concentrations of contaminants are too high to be handled by adsorption process. The problem of raising the efficiency of electroflotation process is currently of relevance. This paper examines how the composition of the medium, i.e. the nature of the electrolyte, surfactants and hardness salts, can influence the extraction of iron, aluminum and chromium hydroxides from aqueous solutions by electroflotation. It was found that the electrolyte (NaCl, Na2SO4) nature has no significant effect on the process. The hydroxide extraction performance can be impacted by the presence of calcium ions regardless of the electrolyte nature. It happens due to the adsorption of Ca2+ on the hydroxide surface, which makes it more hydrophilic. The degree of dispersed phase extraction can be increased due to the introduction of surfactants: didecyldimethylammonium chloride, sodium dodecyl sulfate and a mixture of primary oxyethylated synthetic alcohols. Sodium dodecyl sulfate, which is an anionic surfactant, proved to deliver the best result. The high process efficiency in terms of dispersed phase extraction is due to the hydrophobization of the particle surface by adsorbed sodium dodecyl sulfate and the stabilization of gas bubbles. The particle sizes of iron and chromium hydroxides vary in the range of 0.04 to 4 microns. At the same time, most of the aluminum hydroxide particles are bigger than 10 microns, which can be attributed to the high polymerization ability of aluminum ions and subsequent particle coagulation. The efficiency of electroflotation extraction of chromium, aluminum and iron hydroxides in the presence of calcium ions using anionic surfactant is at least 90%. Additional filtration is recommended to ensure the treated wastewater is in compliance with applicable standard.

FepR as a Central Genetic Target in the Adaptation to Quaternary Ammonium Compounds and Cross-Resistance to Ciprofloxacin in Listeria monocytogenes.

The foodborne pathogen, Listeria monocytogenes, (Lm), frequently undergoes selection pressure associated with the extensive use of disinfectants, such as quaternary ammonium compounds, which are widely used in food processing plants. The repeated exposure to sub-inhibitory biocide concentrations can induce increased tolerance to these compounds, but can also trigger the development of antibiotic resistance, and both increase the risk of food contamination and persistence in food production environments. Although the acquisition of genes can explain biocide tolerance, the genetic mechanisms underlying the adaptive cross-resistance to antibiotics remain unclear. We previously showed that repeated exposure to benzalkonium chloride (BC) and didecyldimethyl ammonium chloride (DDAC) led to reduced susceptibility to ciprofloxacin in Lm strains from diverse sources. Here, we compared the genomes of 16 biocide-adapted and 10 parental strains to identify the molecular mechanisms of fluoroquinolone cross-resistance. A core genome SNP analysis identified various mutations in the transcriptional regulator fepR (lmo2088) for 94% of the adapted strains and mutations in other effectors at a lower frequency. FepR is a local repressor of the MATE fluoroquinolone efflux pump FepA. The impact of the mutations on the structure and function of the protein was assessed by performing in silico prediction and protein homology modeling. Our results show that 75% of the missense mutations observed in fepR are located in the HTH domain of the protein, within the DNA interaction site. These mutations are predicted to reduce the activity of the regulator, leading to the overexpression of the efflux pump responsible for the ciprofloxacin-enhanced resistance.

Ovocidal action of disinfectants against eggs of Passalurus ambiguus

Successful elimination of helminthic diseases, as well as their further prevention, is possible only under the condition of carrying out a complex of organizational and economic, veterinary and sanitary, and special anti-parasitic measures, which must necessarily include disinfestation of places where animals are kept, as well as environmental objects. It is necessary to establish the ability of modern chemical agents to harm certain types of parasites. The research aimed to determine the ovocidal efficiency of disinfectants in different concentrations and exposures against Passalurus ambiguus eggs isolated from domestic rabbits. An experimental test was carried out in laboratory conditions on chemical products of domestic production “Virosan”. (AS – alkyldimethylbenzylammonium chloride, glutaraldehyde) and “Hermecid-VS” (AS – didecyldimethylammonium chloride, glutaraldehyde, benzalkonium chloride). The leading indicator of the effect of disinfectants on the eggs of pasaluris was the value of their disinfestation efficiency. The results of the conducted studies established a high level of ovocidal efficiency of “Virosan” (OE – 100 %) against P. ambiguus eggs at 0.25 % concentration for exposures of 30–60 minutes and 0.5 % concentration for exposures of 10–60 minutes. A satisfactory level of the ovocidal efficiency of “Virosan” was established when using the agent in 0.1 % (30–60 min exposure) and 0.25 % (10 min exposure) concentrations, OE ranges from 62.36 to 82.20 %. An unsatisfactory level of the ovocidal efficiency of “Virosan” was established at 0.1 % of the concentration after exposure for 10 minutes (AS – 47.30 %). Disinfectant “Hermecid-VS” showed a high level of ovocidal efficiency concerning the eggs of pasaluris in 0.1 % concentration for 60 min exposure (OE – 91.45 %) and in 0.25–0.5 % concentration for 10–60 min exposure (AS – 100 %). A satisfactory ovocidal efficiency of “Hermecid-VS” was established when using the product at a concentration of 0.1 % (10 and 30-minute exposures), where OE indicators were 76.25 and 81.91 %, respectively. The obtained data make it possible to recommend disinfectants of domestic production “Virosan” and “Hermecid-VS” in specified concentrations and exposures to control and prevent pasalurosis in rabbits in order to effectively carry out the deinvasion of environmental objects and places where animals are kept.

Assessing the efficacy of novel and conventional disinfectants on Salmonella cross contamination during washing of fresh-cut lettuce and their impact on product shelf life

The effect of the application of different disinfectants on the microbial load and sensory quality of fresh-cut lettuce was evaluated during washing, and after subsequent storage at 4 °C under modified atmosphere packaging (MAP). Different families of potential alternative sanitizers were tested: quaternary ammonium compounds (QACs) as benzalkonium chloride (BZK), and didecyldimethylammonium chloride (DDAC); isothiazolinones (mixture of chloromethylisothiazolinone and methylisothiazolinone, CMIT:MIT 3:1); and, essential oils (carvacrol, CAR). All these disinfectants were effective to inactivate Salmonella (103 CFU/mL) present in wash water. In addition, all tested chemicals could reduce Salmonella on produce to levels >95%, with chlorine and BZK-CAR reaching maximum reductions of 99.0%. These disinfectants also enhanced a reduction in natural microbiota present on the produce. The highest reduction corresponded to free chlorine (50 mg/L) (95.1%), CMIT:MIT (50 mg/L) (Kathon®) (94.5%), and BZK (300 mg/L) (91.3%). However, only free chlorine (50 mg/L), CMIT:MIT (50 mg/L) (Kathon®), and DDAC (100 mg/L) resulted in minimal negative impact on end-product quality during 14-day storage. On the contrary, an adequate sensory quality could be only maintained up to 7 days for produce treated with BZK (300 mg/L).

Impact of material properties in determining quaternary ammonium compound adsorption and wipe product efficacy against biofilms

Disinfectant wipes containing quaternary ammonium compounds (QACs) are widely used within health care. Viscose remains a popular material for these products, although limited information is available concerning its impact on performance against biofilms when compared with alternatives. To identify disinfectant wipe materials and surface properties which optimize product performance against biofilms. Biofilm eradication performance of two commercial viscose-QAC wipes was determined against Staphylococcus aureus and Acinetobacter baumannii dry surface biofilms (DSBs) using an ASTM E2967-based procedure. Additionally, five materials were impregnated with a commercial liquid formulation containing didecyldimethylammonium chloride (DDAC). Following 24h of storage, eradication performance and DDAC content of extracted liquid were determined and compared with material properties, including zeta potential, hydrophobicity and surface area. Under stringent test conditions, eradication of DSBs by commercial products was no greater than equivalent materials impregnated with water. Extract from one viscose-based product contained 89% less DDAC than the impregnation solution, indicating extensive adsorption. Of the other tested materials, viscose performed worst; nearly 70% of DDAC had depleted from material extracts within 24h. In contrast, DDAC depletion from polypropylene extracts was only 25%, and DSB eradication was >100 times greater than viscose. Biofilm eradication performance against both species correlated with the DDAC content of extracts, which, in turn, correlated with zeta potential and hydrophobicity. Biofilm eradication performance of QAC-based wipes was significantly greater when selecting thermoplastic substrates over viscose. However, these materials are non-sustainably sourced and non-biodegradable. This study highlights a need to develop new wipe products that are more effective against biofilms.

Kinetics of Bacterial Adaptation, Growth, and Death at Didecyldimethylammonium Chloride sub-MIC Concentrations.

Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) are standard indexes for determining disinfection effectiveness. Nevertheless, they are static values disregarding the kinetics at sub-MIC concentrations where adaptation, growth, stationary, and death phases can be observed. The understanding of these dynamic mechanisms is crucial to designing effective disinfection strategies. In this study, we studied the 48 h kinetics of Bacillus cereus and Escherichia coli cells exposed to sub-MIC concentrations of didecyldimethylammonium chloride (DDAC). Two mathematical models were employed to reproduce the experiments: the only-growth classical logistic model and a mechanistic model including growth and death dynamics. Although both models reproduce the lag, exponential and stationary phases, only the mechanistic model is able to reproduce the death phase and reveals the concentration dependence of the bactericidal/bacteriostatic activity of DDAC. This model could potentially be extended to study other antimicrobials and reproduce changes in optical density (OD) and colony-forming units (CFUs) with the same parameters and mechanisms of action.

Molecular mechanism of antibiotic resistance induced by mono- and twin-chained quaternary ammonium compounds

The usage of quaternary ammonium compounds (QACs) as disinfectants has increased dramatically since the outbreak of COVID-19 pandemic, leading to potentially accelerated emergence of antibiotic resistance. Long-term exposure to subinhibitory level QACs can lead to multidrug resistance, but the contribution of mutagenesis to resistance evolution is obscure. In this study, we subcultured E. coli K-12 under subinhibitory (0.25 × and 0.5 × Minimum Inhibitory Concentration, MIC) or inhibitory (1 × and 2 × MIC) concentrations of benzalkonium chloride (BAC, mono-chained) or didecyldimethylammonium chloride (DDAC, twin-chained) for 60 days. The sensitivity of QAC-adapted cells to five typical antibiotics decreased significantly, and in particular, the MIC of rifampicin increased by 85 times. E. coli adapted faster to BAC but developed 20–167% higher antibiotic resistance with 56% more mutations under DDAC exposure. The broader mutations induced by QACs, including negative regulators (acrR, marR, soxR, and crp), outer membrane proteins and transporters (mipA and sbmA), and RNA polymerase (rpoB and rpoC), potentially contributed to the high multi-drug resistance. After QACs stresses were removed, the phenotypic resistance induced by subinhibitory concentrations of QACs was reversible, whereas that induced by inhibitory concentrations of QACs was irreversible. The different patterns and molecular mechanism of antibiotic resistance induced by BAC and DDAC is informative to estimating the risks of broader QACs present at varied concentrations in the environment.

Thermal fogging with disinfectants and antifreezes enables effective industrial disinfection in subzero cold-chain environment.

During several local COVID-19 outbreaks in China in 2020, SARS-CoV-2 or its RNA was isolated or detected from frozen food or packages, revealing the lack of effective disinfection measures in the frozen food chain and risk of transmission. We explored the possibility that disinfectant plus antifreeze could be delivered as thermal fog to realize effective disinfection at subzero temperatures. We selected two disinfectant-antifreeze combinations, didecyl dimethyl ammonium bromide (DDAB) - propylene glycol (PPG) and peracetic acid (PAA) - triethylene glycol (TEG), and each combination is used with a custom-optimized thermal fogging machine. The two fogs were tested in -20°C freezer warehouses for their disinfection efficacy against a coronavirus porcine epidemic diarrhoea virus (PEDV) field strain, a swine influenza virus (SIV) field strain, and three indicator bacteria, Escherichia coli, Staphylococcus aureus and Bacillus subtilis endospores. At -20°C, the DDAB-PPG or PAA-TEG thermal fogs settle within 3.5 to 4.5h and effectively inactivated PEDV with median tissue culture infective dose of 10-3.5 0.1ml-1 and SIV-H1N1 with hemagglutination titre of 26 ml-1 within 15-60min. DDAB-PPG could inactivate S. aureus and E. coli vegetative cells (106 cfuml-1 ) within 15-60min but not effective on B. subtilis spores, while PAA-TEG could disinfect B. subtilis spores more effectively than for S. aureus and E. coli. We showed that a practical subzero temperature disinfection technology was effective in killing enveloped viruses and vegetative bacteria or bacterial spores. DDAB-PPG or PAA-TEG thermal fogging may be a practical technology for cold-chain disinfection. This subzero temperature disinfection technology could help to meet the urgent public health need of environmental disinfection in frozen food logistics against pandemic and other potential pathogens and to enhance national and international biosecurity.

Spring poisoning hazards for pets

Warmer weather in the spring may encourage owners and their animals to spend more time outdoors where pets may be exposed to garden products and spring plants. Ingestion of common spring flowering plants, such as tulips, primrose, hyacinth, snowdrops, grape hyacinth, spring crocus, bluebells and daffodil, often cause gastrointestinal signs in pets. Severe poisoning is uncommon but there is a risk of more pronounced clinical signs in some cases and ingestion of plant bulbs may cause gastrointestinal obstruction. Similarly, ingestion of fertiliser may cause gastrointestinal signs and ingestion of bone meal is a potential obstruction risk. Plants containing grayanotoxins, such as Rhododendron and Pieris species cause gastrointestinal and potentially cardiac effects. Patio cleaners and disinfectants containing cationic detergents such as benzalkonium chloride or didecyldimethylammonium chloride, are a particular risk to pets, especially cats. They are usually exposed after walking over a treated surface and then grooming, presenting hours later with salivation, hyperthermia and oral injury. Treatment of pets with clinical signs after exposure to a spring poisoning hazard is supportive.

Adverse Outcome Pathway for Antimicrobial Quaternary Ammonium Compounds

ABSTRACT Quaternary ammonium compounds (QACs) or quats are a large class of antimicrobial chemicals used in households and institutions as sanitizers and disinfectants. These chemicals are utilized as food processing sanitizers, algicides, in the process of water treatment, and preservatives in cosmetics. The aim of this study was to determine an Adverse Outcome Pathway (AOP) whereby two widely used QACs, alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC), may result in respiratory tract and gastrointestinal tract effects. When inhaled or ingested, these QACs are incorporated into the epithelial cell membrane at the point of contact. With sufficient dosage, the epithelial membrane is disrupted, reducing its fluidity, and releasing cellular contents. Further, ADBAC and DDAC might disrupt mitochondrial functions leading to decreased ATP production. Both events might lead to cell death, either attributed to direct lysis, necrosis, or apoptosis. Pro-inflammatory mediators are recruited to the tissue, inducing inflammation, edema, and excess mucus production. The primary tissue-level adverse outcome is epithelial degeneration and dysplasia. Most important, no apparent metabolism or distribution is involved in QAC action. Based upon this knowledge, it is suggested to replace default Uncertainty Factors for risk assessments with a set of Data Derived Extrapolation Factors.

Air Disinfection-From Medical Areas to Vehicle.

Cars with air conditioning systems have become the norm, but these systems can be dangerous for human health as a result of the accumulation of different microorganisms, including pathogenic ones, causing severe allergy or inflammation problems. The novel purpose of this study is 2-fold: on the one hand, to test different disinfection agents on a new area, that is, automobile cabins, and on the other, to compare activity in the gas phase of these agents for disinfection of car air conditioning and cabin surfaces. This study shown that tested disinfectant agents dedicated for decontamination medical areas (agent based on peracetic acid and an agent containing didecyldimethylammonium chloride, 2-phenoxyethanol with cinnamaldehyde) can be successfully used for disinfection car air conditioning and cabin surfaces. Both disinfectants were examined in comparison to a commercial “ready-to-use” spray from a local supermarket dedicated to car air conditioning disinfection. Our research found that very effective agents in this regard were acid stabilized by hydrogen peroxide applied by fumigator, and a combination of didecyldimethylammonium chloride, 2-phenoxyethanol, and cinnamaldehyde applied by atomizer. Tested disinfection procedures of car air conditioning significantly influence the quality of cabin air and surfaces by reducing the amount of microorganisms. The comparison of disinfection properties studied agents in the gas phase reveal statistically significant differences between it effect for disinfection car air conditioning and cabin surfaces. Our research found that very effective agents in this regard were acid stabilized by hydrogen peroxide applied by fumigator, and a combination of didecyldimethylammonium chloride, 2-phenoxyethanol, and cinnamaldehyde applied by atomizer. Tested disinfection procedures of car air conditioning significantly influence the quality of cabin air and surfaces by reducing the amount of microorganisms.

Triple relevant sensitization to didecyldimethylammonium chloride, benzalkonium chloride, and polyhexamethylene biguanide in a hospital cleaner.

None to declare. Supplemental Figure S1. A hand sanitizer containing both benzalkonium chloride (BAC) and didecyldimethylammonium chloride (DDAC). Supplemental Figure S2. Surface cleaning wet wipes containing benzalkonium chloride (BAC, labelled with its synonym ‘alkyldimethylbenzylammonium chloride’), didecyldimethylammonium chloride (DDAC), and polyhexamethylene biguanide (PHMB). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Simultaneous analysis of quaternary ammonium cations and corresponding halide counterions by pyrolysis gas chromatography / mass spectrometry

The use of quaternary ammonium compounds (QACs) as disinfectants has increased tremendously in the COVID-19 pandemic to inactivate Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV2). Dialkyldimethylammonium halides represent a frequently used type among QACs. Different halide anions, each ionically linked to the same quaternary ammonium cation, show clear differences in biocidal activity, toxicity and allergic potential. Likewise, the alkyl chain length at the ammonium cation induces different biocidal efficacy and toxicology. Therefore, the object of this research was to develop a rapid and reliable method for the detection of ammonium cation and halide anion in a single analytical run. For that purpose, a gas chromatography mass spectrometry (GC/MS) method was developed for QACs of the dialkyldimethylammonium type. Pyrolytic conversion of the QACs in the injector port of the gas chromatograph into volatile molecule species allows fast and reliable subsequent GC/MS analysis. The developed method is suited for the determination of both the quaternary ammonium cation and the corresponding halide anion in a single gas chromatographic run. The application of this method to bulk material and standard material of explicitly specified didecyldimethylammonium chloride revealed deviations from the manufacturer’s specifications in a range up to four-fifths. Furthermore, didecyldimethylammonium chloride was detected in a disinfectant that does not comply with the labeling requirement for biocidal ingredients. With the method presented, results can be obtained for disinfectants with minimum effort within seven minutes.

Formation of CsPbCl3 Cubes and Edge-Truncated Cuboids at Room Temperature

In contrast to the normal formation of cubic metal halide perovskite nanocrystals, CsPbCl3 cubes and edge-truncated cuboids have been synthesized by simply mixing CsCl, PbCl2, and sodium dodecyl sulfate (SDS) in dimethyl sulfoxide (DMSO) at room temperature and transferring a small volume of the mixture to toluene to form a precipitate. The tetragonal-phased CsPbCl3 cubes and some rectangular blocks have square and rectangular {100}/{001} faces, while the cuboids have additional {101}/{110} edges. Variation in the amount of PbCl2 transforms cubes to edge-truncated cuboids. Their absorption and emission band positions are nearly identical at 413–416 nm. Despite having relatively large sizes, the CsPbCl3 cubes and edge-truncated cuboids display photoluminescence quantum yields of 6.9 and 2.9%, respectively. Remarkably, adding didecyldimethylammonium chloride (DDAC) surfactant to the reaction mixture leads to a 2–4.6-fold enhancement in the emission intensity. It is envisioned that other cesium lead halide crystals of tunable shapes can be synthesized by using the green reaction conditions.

Functional rGO supported porous PdAg nanospheres self-intercalation catalysts with high stability for direct ethanol fuel cell

The poor long-term stability of anodic catalysts is one of the important factors that hinder the commercial application of direct ethanol fuel cells. The main reason is that toxic intermediates (such as CO) produced in the process of ethanol oxidation are easy to cover the active site, resulting in the catalyst being poisoned and deactivated in a short time. In this work, the prepared catalysts by the co-reduction method use didecyldimethylammonium chloride (DODAC) as the structure directing agent. The PdAg microporous alloy nanospheres in situ growth can effectively separate the GO sheets and slow down the stacking by self-intercalation effect. And introduced Ag into Pd lattice effectively modify the electronic structure of Pd and form OH− at a lower potential, which is helpful the oxidation of CO and weakens the poisoning effect of CO, improving the catalytic performance. After 20,000 s stability test, the residual current density value of mPd1Ag1@FrGO is 659 mA mgPd-1, which is 20 times of Pd/C (JM). After 4 cycles of 20,000 s i-t test, its current density only dropped by 18.2%. In addition, the catalyst mPd1Ag1@FrGO has good regeneration ability. After 6 cycles of regeneration, the residual current density value is 878.1 mA mgPd-1.