Effect Of Chemical Environment Research Articles

Oxygen Vacancy-Laden Confinement Impact on Degradation of Metal Complexes.

Oxygen vacancies (Vo) have been recognized as the superior active site for PS-mediated environmental remediation; however, the formation and activation of Vo associated with the effects of chemical and spatial environments remain ambiguous. Herein, attributing to the low defect-formation energy of Vo in the presence of sulfonate groups, an in situ nucleating Vo-laden CuO nanosheet was deliberately fabricated inside the phase of a sulfonated mesoporous polystyrene substrate (Vo-CuO@SPM). The as-prepared nanocomposite demonstrated an excellent treatment efficiency toward metal complexes [Cu-EDTA as a case] with ignorable Cu(II) leaching, and it can be repeatedly employed for 25 recycles (not limited). Mechanistically, the electron transfer and the mass transport for PDS nonradical activation were proved to be substantially enhanced by the delocalized electrons and with the assistance of the microchannel environment. This work not only establishes insight into the formation of oxygen vacancies but also reveals the PS activation mechanism in the spatially confined sites.

Second-Shell N Dopants Regulate Acidic O2 Reduction Pathways on Isolated Pt Sites.

Pt is a well-known benchmark catalyst in the acidic oxygen reduction reaction (ORR) that drives electrochemical O2-to-H2O conversion with maximum chemical energy-to-electricity efficiency. Once dispersing bulk Pt into isolated single atoms, however, the preferential ORR pathway remains a long-standing controversy due to their complex local coordination environment and diverse site density over substrates. Herein, using a set of carbon nanotube supported Pt-N-C single-atom catalysts, we demonstrate how the neighboring N dopants regulate the electronic structure of the Pt central atom and thus steer the ORR selectivity; that is, the O2-to-H2O2 conversion selectivity can be tailored from 10% to 85% at 0.3 V versus reversible hydrogen electrode. Moreover, via a comprehensive X-ray-radiated spectroscopy and shell-isolated nanoparticle-enhanced Raman spectroscopy analysis coupled with theoretical modeling, we reveal that a dominant pyridinic- and pyrrolic-N coordination within the first shell of Pt-N-C motifs favors the 4e- ORR, whereas the introduction of a second-shell graphitic-N dopant weakens *OOH binding on neighboring Pt sites and gives rise to a dominant 2e- ORR. These findings underscore the importance of the chemical environment effect for steering the electrochemical performance of single-atom catalysts.

Water-Mediated Charge Transfer and Electron Localization in a Co3Fe2 Cyanide-Bridged Trigonal Bipyramidal Complex.

The effects of temperature and chemical environment on a pentanuclear cyanide-bridged, trigonal bipyramidal molecular paramagnet have been investigated. Using element- and oxidation state-specific near-ambient pressure X-ray photoemission spectroscopy (NAP-XPS) to probe charge transfer and second order, nonlinear vibrational spectroscopy, which is sensitive to symmetry changes based on charge (de)localization coupled with DFT, a detailed picture of environmental effects on charge-transfer-induced spin transitions is presented. The molecular cluster, Co3Fe2(tmphen)6(μ-CN)6(t-CN)6, abbrev. Co3Fe2, shows changes in electronic behavior depending on the chemical environment. NAP-XPS shows that temperature changes induce a metal-to-metal charge transfer (MMCT) in Co3Fe2 between a Co and Fe center, while cycling between ultrahigh vacuum and 2 mbar of water at constant temperature causes oxidation state changes not fully captured by the MMCT picture. Sum frequency generation vibrational spectroscopy (SFG-VS) probes the role of the cyanide ligand, which controls the electron (de)localization via the superexchange coupling. Spectral shifts and intensity changes indicate a change from a charge delocalized, Robin-Day class II/III high spin state to a charge-localized, class I low spin state consistent with DFT. In the presence of a H-bonding solvent, the complex adopts a localized electronic structure, while removal of the solvent delocalizes the charges and drives an MMCT. This change in Robin-Day classification of the complex as a function of chemical environment results in reversible switching of the dipole moment, analogous to molecular multiferroics. These results illustrate the important role of the chemical environment and solvation on underlying charge and spin transitions in this and related complexes.

WD‐XRF technique for speciation of iron and quantification of its oxidation states in geological samples using L‐series of iron X‐ray spectrum

AbstractWavelength dispersive X‐ray fluorescence (WD‐XRF) spectrometry is a fast and widely used technique for elemental analysis of geological samples from Na to U. However, it has seldom been applied for quantitative determination of oxidation states of elements in complex matrices. In this study, we present a method to determine the oxidation states of iron in geological samples by WD‐XRF. We used the FeLα1,2 fluorescence line as a tool for iron speciation and Fe(II)/Fetotal ratio determination. We found that the normalized intensity (peak height) of FeLα1,2 fluorescence line was linearly correlated with the spin multiplicity (2S + 1) of ferrous and ferric content in the samples. To account for the matrix effects of chemical environment (matrix and chemical bonding) on FeLα1,2 fluorescence line, we introduced a chemical index factor (μ) that enabled accurate determination of Fe(II)/Fetotal ratio in different types of geological samples. The method was validated using international certified reference materials and their mixtures and obtained promising results, with only 6 out of 55 determinations showing relative error more than 5% of the certified values.

Mechanics of Durability of Structural Concrete: a New Approach to the Phenomenon of Degradation. Part 1. Shrinkage

Concrete is a material widely used in construction works and buildings that support people’s lives. The operability of concrete structures can be maintained for a long time if such structures are properly designed and built. The article proposes a new approach to the mechanics of durability to establish a systematic prediction and assessment of the be- havior of reinforced concrete structures depending on time. The chemical and mechanical wear of cement materials over time due to chemical reactions, environmental effects and external loads is described by physico-chemical models of reaction, transfer, destruction and their compounds. In addition, the operability of concrete structures over time is discussed. The outlines of several representative research projects on the mechanics of durability are presented.

Modeling Chemical Microenvironments in Porous Copper Electrodes for CO2 Reduction at Elevated Current Densities

Electrochemical CO2 reduction (CO2R) presents a promising pathway toward the reuse of CO2 emitted during the production of industrial commodities (e.g., cement, steel, and plastics) to form value-added commodities and fuels at ambient temperatures and pressures with renewably generated electrons. Copper (Cu) catalysts demonstrate the ability to convert CO2 to multicarbon (C2+) products. Additionally, 3-D structured porous Cu electrodes can facilitate the operation of CO2R to C2+ at significantly elevated current densities by enhancing the delivery of CO2 to catalytic active sites on Cu, offering the potential to translate lab-scale understanding to industrial operation. Nonetheless, there still exist selectivity limitations in porous electrode systems due to poor control of the chemical microenvironment, (i.e., the local pH, CO2 activity, and CO intermediate management), in these complex electrodes. Therefore, resolving microenvironment in porous Cu electrodes will be critical to advancing these systems towards industrialization.In this talk, we explore the use of continuum modeling to resolve and understand the effects of mass transfer and chemical environment in electrochemical CO2 reduction in porous Cu electrodes. We explore two scenarios of porous Cu electrodes performing electrochemical CO2 reduction. The first is the operation of a device employing a bipolar membrane (BPM) in reverse bias, wherein modeling reveals that the proton flux generated by the BPM substantially lowers the pH of the porous electrode and promotes selective CH4 and HCOOH generation. The second is the use of a micro-structured porous electrode that employs an anion-exchange membrane and more selectively generates C2+ products. 2-D modeling reveals heterogeneities in the porous electrode enable hotspots of increased pH that locally enhance C2+ selectivity. Ultimately, this talk underscores the powerful ability of continuum modeling to resolve microenvironments at spatial resolutions beyond what is achievable experimentally, as well as to link changes in microenvironment to changes in local selectivity. These simulations will rationalize and guide the engineering of microenvironment in next-generation porous electrodes for CO2 reduction to C2+ products at industrial scales.

The Effect of Chemical Environment and Temperature on the Domain Structure of Free-Standing BaTiO3 via In Situ STEM.

Ferroelectrics, due to their polar nature and reversible switching, can be used to dynamically control surface chemistry for catalysis, chemical switching, and other applications such as water splitting. However, this is a complex phenomenon where ferroelectric domain orientation and switching are intimately linked to surface charges. In this work, the temperature-induced domain behavior of ferroelectric-ferroelastic domains in free-standing BaTiO3 films under different gas environments, including vacuum and oxygen-rich, is studied by in situ scanning transmission electron microscopy (STEM). An automated pathway to statistically disentangle and detect domain structure transformations using deep autoencoders, providing a pathway towards real-time analysis is also established. These results show a clear difference in the temperature at which phase transition occurs and the domain behavior between various environments, with a peculiar domain reconfiguration at low temperatures, from a-c to a-a at ≈60°C. The vacuum environment exhibits a rich domain structure, while under the oxidizing environment, the domain structure is largely suppressed. The direct visualization provided by in situ gas and heating STEM allows to investigate the influence of external variables such as gas, pressure, and temperature, on oxide surfaces in a dynamic manner, providing invaluable insights into the intricate surface-screening mechanisms in ferroelectrics.

Effect of chemical environment on copper tailings reinforced by microbially induced carbonate precipitation

The accumulation of large amounts of tailings produced in the beneficiation process of ores is one of the main challenges for mining industry related to their retention in tailings ponds and the potential hazard of tailings dams’ failure. To enhance stability of tailings dams, microbially induced carbonate precipitation (MICP) has emerged as a novel technique for tailings treatment. However, the intricate chemical environment within tailings ponds affects the growth of microorganisms and can adversely impact the efficiency and effectiveness of MICP. This study investigates for the first time the factors that influence the growth of Sporosarcina pasteurii in a copper tailings pond characterized by weak acidity and the presence of copper ions. The adverse effects of the chemical environment in copper tailings ponds on MICP are investigated through mechanical tests and microscopic analyses on four groups of MICP-reinforced copper tailings. The results revealed that copper ions inhibited the growth of bacteria, while pH had an insignificant effect on bacteria. Hence, copper ions are identified as the main factor that weakens the reinforcing effect of MICP on copper tailings. Even though the weakly acidic environment has been shown to have a minor impact on the performance of MICP-reinforced copper tailings, maintaining the acid resistance of the reinforced tailings is crucial for ensuring long-term reinforcement effectiveness. It was also found that increasing the concentration of the bacterial solution and applying it in multiple injections, while controlling the pH of the cementation solution, could enhance the survival rate and activity of bacteria and improve the carbonate sedimentation environment. This would strengthen the reinforcing effect of MICP. The results demonstrated that MICP has promising potential for tailings treatment, but it is essential to address the adverse effects of the chemical environment in tailings ponds. The findings from this study provide valuable reference data for subsequent field experiments and engineering practices and facilitate the application of biomineralization in tailings ponds.

Development of super-hydrophobic surface using Tio2 to reduce adverse effects of environmental pollutants on buildings

The development of self-cleaning surfaces in recent years has been significant in preserving buildings from environmental contaminants and improving visual durability. Titanium dioxide (or titania), a photocatalyst, is used with cement to improve aesthetic durability and de-pollution properties. Super hydrophilic materials were developed by covering glass, ceramic tiles, or polymers with the semiconducting photocatalyst titanium dioxide (TiO2). Grease, grime, and organic pollutants disintegrate when TiO2 is exposed to light and are simply swept away by water (rain). Ink and vehicle smoke are utilised to evaluate the self-cleaning properties of TiO2-containing concretes, and the oxidation of carbons (COx), gaseous atmospheric pollutants responsible for acid rain and photochemical smog, is explored using nano titanium dioxide. The research allowed for the identification of photo-oxidation mechanisms of stain and COx on TiO2-containing cement, as well as parallels and differences with pure unsupported TiO2. Engineering TiO2 particles with certain crystallite sizes and modifying the photocatalyst electrokinetic properties by changing the overall pKa of the TiO2 surface have both been shown to be efficient approaches for controlling the attractive features of ion-ion correlation forces. The effects on applications in a concrete building, specifically on the exterior surface, to improve overall photocatalytic activity are reviewed. The experimental data on photocatalytic performances measured for regular and nano-coated samples are examined regarding photocatalyst qualities and the effect of cement's chemical environment on titania particles. The research allowed for the identification of photo-oxidation mechanisms of stain and COx on TiO2-containing cement, as well as parallels and differences with pure unsupported TiO2.

Crystal structure effects on the Co-sputtered p-type Fe2-xSnxO3 hydrogen gas sensors

Fe2-xSnxO3 structures grown by RF-DC magnetron co-sputtering. The band gap of Fe2O3, SnO2, Fe2-xSnxO3 structure was calculated as 2.86, 4.06, 2.77 eV, respectively. The Fe2O3 thin film has shown a tetragonal as well as the SnO2 structure, however, the Fe2-xSnxO3 (0 < x < 1) has shown rhombohedral structure. XPS measurements have shown change in binding energy which is due to the electron exchange of tin-iron with oxygen, and iron - tin oxide structure. This binding energy increases slightly with the chemical environment effect. The films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM). In AFM images was seen that the iron oxide structure was pyramidal and the tin oxide structure was spherical, similar to the SEM image. The response of the film to hydrogen gas was measured at flow values of 100, 500 and 1000 ppm at 300 °C. Fe2O3 thin films show 46%, SnO2 61% and, Fe2-xSnxO3 6.5% response to 1000 ppm H2 gas. It is seen that the gas sensor response was affected by the morphological and structural features of the grown film.

DFT potentials from a chemical perspective: Anatomy of electron (de)localization in molecules and crystals.

We introduce a fermionic potential, , as a comprehensive measure of electron (de)localization in atomic-molecular systems. Unlike other common descriptors as ELF, LOL, etc., it characterizes all physical effects responsible for (de)localization of electrons, namely: an exchange hole depth, its tendency to change, a sensitivity of an exchange correlation hidden in a pair density and kinetic potential to local variations in electron density. Wells in the distribution correspond to the domains of maximum electron localization, while the potential's barriers prevent delocalization of electrons through them. It also estimates bond orders and successfully reveals the impact of chemical modifications or environmental effects on the delocalization of electrons in molecules and crystals. The components provide a unique opportunity to compare the influence of the mentioned physical effects on electron (de)localization. This merges physical and chemical views of electron delocalization using functions appearing in density functional theory.

Multiscale model to resolve the chemical environment in a pressurized CO2-captured solution electrolyzer

The community of electrochemical CO2 reduction is almost exclusively focused on gaseous CO2-fed electrolyzers. Here, we proposed a pressurized CO2-Captured solution electrolyzer to produce solar Fuel of CO (abbreviated “CCF”) without the need to regenerate gaseous CO2. Specifically, we developed an experimentally validated multiscale model to quantitatively investigate the effect of pressure-induced chemical environment and to resolve the complex relationship between this effect and the activity and selectivity of CO production. Our results show that the pressure-induced variation of the cathode pH has a negative effect on the hydrogen evolution reaction, whereas the species coverage variation positively affects CO2 reduction. These effects are more pronounced at pressures below 15 bar (1 bar = 101 kPa). Consequently, a mild increase in the pressure of the CO2-captured solution from 1 to 10 bar leads to a dramatic enhancement in selectivity. Using a commercial Ag nanoparticle catalyst, our pressurized CCF prototype achieved CO selectivity higher than 95% at a low cathode potential of −0.6 V versus reversible hydrogen electrode (RHE), comparable to that under the gaseous CO2-fed condition. This enables the demonstration of a solar-to-CO efficiency of 16.8%, superior to any known devices with an aqueous feed.

Effect of local chemical environment on the point defects in AlNbTiZr refractory high entropy alloys

The effect of local chemical environment (i.e., type and content of atom neighboring to defects) on the point defect properties has been thoroughly investigated in bcc AlNbTiZr refractory high-entropy alloys (HEAs). It has been shown that the randomness of local chemical environments in AlNbTiZr HEAs leads to a wide distribution of vacancy and interstitial formation energy rather than to definitive values. One interesting aside here is that the number of Al and Nb atoms locating at the first-nearest neighbor (1nn) of vacancy drives the evolution of vacancy formation energy (VFE) in AlNbTiZr system, as vacancies preferred Al-rich and Nb-poor environments. What another worth noticing is that the most stable interstitial defects are in the form of dumbbells. What's more, the Al-Al dumbbell is the easiest interstitial defect while the Zr-Zr dumbbell is the least according to the lowest formation energy and electronic characteristics. Along with the results of vacancies preferred Al-rich environments, Al in AlNbTiZr can stabilize the single vacancy and inhibit its migration and diffusion to form large-size vacancy clusters. Therefore, the initial irradiation resistance can be improved by adjusting the concentration and distribution of Al in AlNbTiZr. One can infer from the results obtained present that it is beneficial in improving the irradiation resistance by controlling different processing experimentally methods to increase the occurrence of Al-Al arrangement in AlNbTiZr high-entropy alloys.

Structural equation model was used to evaluate the effects of soil chemical environment, fertility and enzyme activity on eucalyptus biomass.

This paper aims to reveal the effects of multi-generational succession of eucalyptus on soil fertility, organic structure and biological properties. Soil samples were collected from eucalyptus plantations of different stand ages (5, 11, 17 and 21 years old) in a typical area in south Asia, soil organic fraction structure and content characteristics were investigated using Fourier transform infrared (FTIR), and structural equation modelling (SEM) was used to explore influences of soil fertility, enzyme activity and organic fraction on stand biomass. FTIR analysis showed that 11 infrared absorption peaks existed in the soils of this study area, attributed to silicates, aromatics, carbonate ions, sugars, esters, polysaccharides, aliphatic hydrocarbons and phenolic alcohols. Combined with the results of peak area integration, the content of esters, aromatics and phenolic alcohols was significantly higher in 17- and 21-year-old stand soils than in control soils. The results of SEM showed that organic components were negatively related (p < 0.01) to enzyme activity and biomass, with standardized coefficients of 0.53 and 0.49, respectively. In summary, multi-generation succession of eucalyptus trees can change the structure of soil organic functional group composition and promote the enrichment of aromatic and phenolic alcohol functional groups. Such changes can directly inhibit the increase in eucalyptus biomass and indirectly negatively affect biomass by inhibiting enzyme activity.

Piperazine ring toxicity in three novel anti-breast cancer drugs: an in silico and in vitro metabolic bioactivation approach using olaparib as a case study.

The metabolic activation of small-molecule drugs into electrophilic reactive metabolites is widely recognized as an indicator of idiosyncratic adverse drug reactions (IADRs). Three novel anti-breast cancer drugs containing piperazine rings, ribociclib (Kisqali®, RCB), abemaciclib (Verzenio®, ABC), and olaparib (Lynparza®, OLP), were selected to study the effect of different chemical environment on the piperazine ring activation using in silico and in vitro metabolic experiments. ABC and RCB were previously studied and we noticed the piperazine ring in ABC could be strongly bioactivated generating more reactive intermediates than piperazine ring in RCB. OLP was further used as a case study to show the power of in silico software to predict the piperazine ring activation that was approved using in vitro experiments. Initially, predictions of susceptible sites in the metabolism and reactivity pathways were performed using the StarDrop P450 model and XenoSite reactivity tool, respectively. Later, in vitro OLP metabolites were characterized based on rat liver microsomes (RLMs) using KCN (trapping agent) using LC-MS/MS. The main goal of the current study was to answer the question of whether the presence of a piperazine ring in the chemical structure should be always considered a structural alert. Piperazine ring in RBC and ABC was bioactivated through a metabolic sequence that involves the hydroxylation of α-carbon to the tertiary nitrogen atoms of the piperazine ring. In the case of OLP, no cyano adduct was formed due to the presence of two carbonyl groups attached to the two nitrogen atoms of the piperazine ring (neutral amide groups). From the results, piperazine ring in certain cases should not be considered as a structural alert as in the case of OLP due to the presence of two electron withdrawing group that stops the proposed toxicity. Also blocking the bioactive center (α-carbon) using steric hindrances such as methyl group, also the isosteric replacement of α-carbon hydrogen with fluoro atom can aid in reducing the toxic side effects of ABC and RCB. These experiments were done in vitro through incubation with RLMs in the presence of KCN. Also, the results are supported by data generated from in silico software. In the future, drug discovery studies using this concept could be undertaken, allowing for the development of new drugs with reasonable safety profiles. Overall, in vitro RLMs incubations and in silico experiments were able to predict successfully that the piperazine ring should not always be considered a structural alert.

Structures and conformational dynamics of DNA minidumbbells in pyrimidine-rich repeats associated with neurodegenerative diseases

Expansions of short tandem repeats (STRs) are associated with approximately 50 human neurodegenerative diseases. These pathogenic STRs are prone to form non-B DNA structure, which has been considered as one of the causative factors for repeat expansions. Minidumbbell (MDB) is a relatively new type of non-B DNA structure formed by pyrimidine-rich STRs. An MDB is composed of two tetraloops or pentaloops, exhibiting a highly compact conformation with extensive loop-loop interactions. The MDB structures have been found to form in CCTG tetranucleotide repeats associated with myotonic dystrophy type 2, ATTCT pentanucleotide repeats associated with spinocerebellar ataxia type 10, and the recently discovered ATTTT/ATTTC repeats associated with spinocerebellar ataxia type 37 and familial adult myoclonic epilepsy. In this review, we first introduce the structures and conformational dynamics of MDBs with a focus on the high-resolution structural information determined by nuclear magnetic resonance spectroscopy. Then we discuss the effects of sequence context, chemical environment, and nucleobase modification on the structure and thermostability of MDBs. Finally, we provide perspectives on further explorations of sequence criteria and biological functions of MDBs.

Point defect properties of the VCrMnFe0.33 multi-principal alloy from first-principles calculations

We performed first-principles calculations to explore the point defect formation and migration properties and the corresponding chemical environment effects for a bcc VCrMnFe 0.33 multi-principal alloy. The results indicate that the vacancy formation energies vary with local environment, and vacancies favor Mn-rich surroundings. The exchange between vacancies and V atoms presents lower energy barriers due to the large atomic size of V. Moreover, interstitial calculations found that [110] direction dumbbells take up more than 93%, suggesting a slow defect diffusion. The large V interstitials can substitute neighboring atoms and leave the squeezed atom forming dumbbells with its surroundings. Our investigation indicates that this low-activation multi-principal alloy may exhibit promising irradiation resistance due to its special defect properties. All data generated or analyzed during this study are included in this published article.

Extraction processes reduce polyphosphate ion migration, dispersion and diffusion as detected with gel electrophoresis and 31 P DOSY NMR.

Inorganic polyphosphates (polyPs) have been identified in eukaryotic and prokaryotic cells alike. Various extraction methods have been optimized as a necessary step before identification and measurement of these polymers. Three commercially available sodium polyP glasses were either dissolved or dissolved and extracted by two commonly used polyP extraction techniques - perchloric acid or buffered phenol-chloroform. The products were separated by polyacrylamide gel electrophoresis (PAGE), stained with toluidine blue O, and the migration results quantitatively compared. Both extraction processes reduced the relative migration distances of the peak and leading edges, and the stained band lengths, suggesting reduced polyP migration and dispersion. 31 P diffusion-ordered spectroscopy nuclear magnetic resonance confirmed that polyP extraction by perchloric acid or phenol-chloroform processes reduced polyP diffusion coefficients and suggested hydrolytic degradation with stronger end-chain signals. Reduced polyP diffusivity after extraction makes possible an overestimation of synthetic polyP chain length assignment when compared to unextracted polyP ladders with PAGE. The mechanism(s) for reduced synthetic polyP diffusion after extraction and intracellular chemical environment effects on migration are not known.

Nanoscale visualization of metallic electrodeposition in a well-controlled chemical environment

Liquid phase transmission electron microscopy (TEM) provides a useful means to study a wide range of dynamics in solution with near-atomic spatial resolution and sub-microsecond temporal resolution. However, it is still a challenge to control the chemical environment (such as the flow of liquid, flow rate, and the liquid composition) in a liquid cell, and evaluate its effect on the various dynamic phenomena. In this work, we have systematically demonstrated the flow performance of an in situ liquid TEM system, which is based on ‘on-chip flow’ driven by external pressure pumps. We studied the effects of different chemical environments in the liquid cell as well as the electrochemical potential on the deposition and dissolution behavior of Cu crystals. The results show that uniform Cu deposition can be obtained at a higher liquid flow rate (1.38 μl min−1), while at a lower liquid flow rate (0.1 μl min−1), the growth of Cu dendrites was observed. Dendrite formation could be further promoted by in situ addition of foreign ions, such as phosphates. The generality of this technique was confirmed by studying Zn electrodeposition. Our direct observations not only provide new insights into understanding the nucleation and growth but also give guidelines for the design and synthesis of desired nanostructures for specific applications. Finally, the capability of controlling the chemical environment adds another dimension to the existing liquid phase TEM technique, extending the possibilities to study a wide range of dynamic phenomena in liquid media.

1-Methyl-1H-1,2,4-triazole as the main marker of 1,1-dimethylhydrazine exposure in plants.

With their wide application in chemical industry, human health and environmental toxic effects of hydrazines arise extensive concerns. Although hydrazine exposure is known to lead to inhibition of seed germination and seedling growth in plants, there are few reports about the mechanism of oxidation or transformation ways of hydrazines in plant tissue. In this research, garden cress (Lepidium sativum L.) and zucchini (Cucurbita pepo L.) were used as model plant objects to study 1,1-dimethylhydrazine exposure in vitro using the GC-MS system. The seed germination and plant growth experiments were carried out in Petri dishes using an aqueous media. Among the detected 1,1-dimethylhydrazine transformation products in plant tissues, 1-methyl-1H-1,2,4-triazole had the highest intensity and reproducibility. In our research, 1-methyl-1H-1,2,4-triazole formed at all contaminant concentrations in an extremely short period. This preliminary study determined 1,1-dimethylhydrazine environment contamination by detecting 1-methyl-1H-1,2,4-triazole in combination with other transformation products.