Effect Of Dichloromethane Research Articles

Experimental Design and Multiple Response Optimization for the Extraction and Quantitation of Thirty-Four Priority Organic Micropollutants in Tomatoes through the QuEChERS Approach

The chemical contamination in fruit and vegetables represents a challenging analytical issue, with tomatoes deserving to be investigated as they are fundamental components of the Mediterranean diet. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs contamination is of serious concern, due to particulate deposition and to uptake from contaminated soils and water. However, time-consuming, non-simultaneous and/or non-eco-friendly extraction procedures are typically used to investigate organic contamination in tomatoes, with nitro-PAHs that have not yet been studied. Based on these premises, this work reports the development of a QuEChERS-based approach, coupled with gas chromatography/mass spectrometry, for the simultaneous determination of 16 PAHs, 14 PCBs and 4 nitro-PAHs in three tomato cultivars. The effect of dichloromethane, cyclohexane and acetone, as well as of four clean-up phases were studied through the advanced combination of full factorial experimental design and multiple response optimization approaches. The final protocol, based on cyclohexane extraction followed by a double purification step with primary secondary amine and octadecyl silica and a sulfuric acid oxidation, led to 60–120% recoveries (RSD% < 15%). Good repeatability (inter-day precision <15%) and negligible matrix effect (<16%) were confirmed and the protocol was applied to the analysis of real tomato samples purchased in a local market.

Spectrum-effect relationship between serum HPLC fingerprints and activation of blood circulation and removal of blood stasis by Chuanxiong


 
 
 
 Purpose: To study the active ingredients of Chuanxiong (CX) in promoting blood circulation and removing blood stasis.
 Methods: Blood-activating effects and serum HPLC fingerprints of CX extracts from different parts of China were studied and the spectrum-effect relationship between them was established by grey correlation analysis.
 Results: After treatment with CX extracted using different solvents, hemorheology indices were lower than those in the model group, and the effect of dichloromethane was better than that of other solvents (p < 0.05 or p < 0.01). There were 6 common peaks by fingerprint analysis. Peaks 1 - 5 were identified as senkyunolide I, senkyunolide H, senkyunolide A, coniferyl ferulate and ligustilide, respectively.
 Conclusion: Analysis of the spectrum–effect relationship indicates the contribution of the five components to the blood-activating effect of CX. The findings lend some scientific justification for using CX to remove blood stasis, and selection of quality evaluation indices for CX.
 
 
 

The Effect of Dichloromethane on Product Separation during Continuous Hydrothermal Liquefaction of Chlorella vulgaris and Aqueous Product Recycling for Algae Cultivation

Dichloromethane (DCM) is a solvent commonly used in laboratories for microalgae hydrothermal liquefaction (HTL) product separation. The addition of DCM would lead to an “overestimation effect” of biocrude yield and diminish biocrude quality. However, it is currently not clear to what extent this overestimation effect will impact a continuous HTL process. In this study, Chlorella vulgaris microalgae was processed in a continuous stirred tank reactor at different temperatures (300, 325, 350, 375, and 400 °C) at 24 MPa for 15 min holding time. Two separation methods were applied to investigate the effect of using DCM in a cHTL product separation procedure in terms of product yield, biocrude elemental content, and aqueous product (AP) composition. Subsequently, the feasibility of reusing AP for algae cultivation has been evaluated. Results suggest that 350 °C is the optimal temperature for cHTL operation, leading to the highest biocrude yield, and an average increase in biocrude yield of 9 wt % was achieved when using DCM in cHTL product separation. Within the temperature range investigated, an average biocrude yield estimation can be proposed by yieldnon-DCM ≈ 0.818 × yieldDCM. The AP has been characterized by total organic carbon and total nitrogen, high-performance liquid chromatography, and inductively coupled plasma optical emission spectroscopy. Results show that at 350–375 °C more nitrogen and other ions were directed into the AP, which could be advantageous in nutrient recovery. With the help of optical density testing, algae was shown to exhibit a better growth using AP with activated carbon absorption purification treatment as compared to the standard medium. The recovery of water and nutrients from the HTL-AP could improve the economics of a microalgae biorefinery process.

Effect of dichloromethane on the performance and yield rate of pure green petroleum coke products

The self-sintering process provides the possibility to prepare high-performance special carbon graphite material. However, the problem of extremely low yield caused by products cracking has not been effectively solved, which greatly limits its commercialization process. This paper creatively proposes that after removing the light component volatile substances of pure green petroleum coke (GPC) by dichloromethane (CH2Cl2). Then, carbon materials with a yield of about 100% was prepared by compression molding at 10 MPa and calcinating at 1050 °C for 4 h. Compared with GPC, the adhesion, self-sintering and mechanical properties of the product can also be greatly improved by this method. And its compressive and flexural strengths are increased by 89.2% and 35.2%, respectively. This exciting discovery can provide new research ideas and directions for the self-sintering process to prepare high-performance special carbon graphite material.

Effect of dichloromethane and toluene on the structure, property, and Al electrodeposition in 1-butyl-3-methylimidazolium chloroaluminate ionic liquid

The electrodeposition of aluminum in ionic liquid has broad application prospects, and additives are an effective way to improve the performance of the aluminum coating. However, the relevant mechanism behind this remains to be clarified. In the present work, the effects of dichloromethane (DCM) and toluene (C7H8) on the microstructure, physicochemical properties, and aluminum electrodeposition with 1-butyl-3-methylimidazolium chloride/aluminum chloride ([BMIM]Cl/AlCl3) were studied using quantum chemistry and molecular dynamics simulation. It is found that DCM easily forms hydrogen bonds with anions and cations of ionic liquids. Since DCM is distributed between anion and cation, the distance between the anion and cation increases, and the interaction energy decreases. As a result, the diffusion ability of anions and cations is enhanced, and the aluminum complex anions tend to exist in the form of \begin{document}${\rm{A}}{{\rm{l}}_2}{\rm{Cl}}_7^ - $\end{document} . The viscosity of the system decreases, and the conductivity increases, so the electrochemical properties of the system are significantly improved, which are in good agreement with the experimental values. C7H8 is adsorbed on the protruding part of the electrode surface in a flat way, which plays a leveling role and results in a flat white coating. Alternatively, DCM easily interacts with the electroactive ion \begin{document}${\rm{A}}{{\rm{l}}_2}{\rm{Cl}}_7^ - $\end{document} , which makes it difficult to reduce this electroactive ion. At the same time, the concentration of the electroactive ion decreases as the concentration of the additive is increased, which leads to a large overpotential in the electrochemical process, resulting in a decrease in the electrode reaction rate that plays a role in grain refinement. Moreover, the interaction between DCM and cations is also strong, and they can be adsorbed on the protruding part of the electrode surface during the electrochemical process, playing a certain leveling role. Therefore, the addition of DCM can obtain specular gloss deposits. The effect of C7H8 on the interaction between anions and cations is not as good as DCM, which consequently results in inferior electrochemical properties compared to DCM. Therefore, DCM is more favorable for the electrodeposition of aluminum than the aromatic hydrocarbon C7H8.

Morphological effect of dichloromethane on alfalfa (Medicago sativa) cultivated in soil amended with fertilizer manures

In this work, we investigated the morphological effect of dichloromethane (DCM) on alfalfa (Medicago sativa) plant. We studied in vitro the influence of its concentration on alfalfa germination. The plants were placed in pots for 15 weeks, and exposed to increasing concentrations of DCM (50 µg L−1 and 84 mg L−1). In addition, we examined the effect of two manures (cow and sheep), which were applied to a contaminated soil, on alfalfa plant growth. The effect of the presence of dichloromethane is obvious even in plant–soil manure system. In fact, in the event of contamination, the soil–cow manure mixture represents the best setting medium for the Alfalfa plant compared to other environments, regardless of the contamination level. Indeed, the presence of two types of manure does not allow the suppression of the inhibitory effect of dichloromethane on the mass of the dry matter of the aerial part which is 18.38% for the cow manure-amended soil and 13.96% for the sheep manure-amended soil.

Invivo Anti-Trypanosomal Activity of the Leaf Extracts of Albizia Schimperiana (Fabaceae) Against Trypanosoma Congolense Infection in Mice

Objectives: The objective of this study was to evaluate effect of dichloromethane (DCM) and methanol (MeOH) extracts of the leaf of Albizia schimperiana against Trypanosoma congolense using in vivo mice models. Methods: The leaf of the plant was extracted by maceration technique using DCM and absolute MeOH to obtain the corresponding crude extracts. The extracts were screened for secondary metabolites and anti-trypanosomal activity of the crude extracts was evaluated at doses of 50, 100, 200 and 400 mg/kg in Swiss albino mice infected with T. congolense isolated from natural infection of cattle. The animals were monitored for test parameters including parasitemia, packed cell volume, rectal temperatures, body weight and survival. Results: The acute toxicity test showed that both solvent extracts were safe at doses of up to 2 g/kg. The methanol extract at 100, 200 and 400 mg/kg showed a statistically significant (p 0.05) reduction in parasitemia except 400 mg/kg dose. Conclusion: It can conclude that MeOH extract has promising activity against T. congolense in mice by reducing the levels of parasitemia and the activities may be due to presence of alkaloid, flavonoid and saponins which are responsible for anti-trypanosomal activity.

Characterization of the Biocidal Spectrum of Extracellular Filtrates of Microcystis aeruginosa.

The effect of dichloromethane (DCM) and ethyl acetate (EA) extract of a cyanobacterium, Microcystis aeruginosa was evaluated against unicellular cyanobacteria and the phytopathogenic fungus Rhizoctonia solani. Fractionation of the filtrate showed the presence of five spots of different Rf values on silica gel coated plates indicating the presence of a number of compounds in the extract. A marked reduction in growth (52%) of the fungus was recorded on the plates supplemented with cyanobacterial extract, indicating the involvement of anti-fungal metabolite(s). The extract did not show any negative influence on seed germination and growth of seedlings of wheat, rice and mung, emphasizing the suitability of the compound for use in agriculture.

Effect of Dichloromethane on Transport, Thermal, and Thermal‐Mechanic Properties of Amorphous Glass Poly(Ether Imide) Films

In this work the interaction effect of dichloromethane on amorphous glassy poly(ether imide) (PEI) films was analyzed from the correlation between transport, thermal, and mechanical properties. The resulting sorption curves were anomalous two‐stage in the solvent activity range 0–0.34 and pseudo‐Fickian for the solvent activity range 0.40–0.50. From a generalized diffusion equation to describe the combination of Fickian and Case II mechanisms we found that the velocity of solvent penetration (v) was higher than the diffusion coefficient (D) for all solvent activities studied. It was observed from the cluster function and the mean size cluster that solvent–solvent interactions may occur at higher solvent activities. Thermal differential scanning calorimetry (DSC) and thermal gravimetric analysis [(TGA) and thermal mechanical (DMTA)] characterization showed that the solvent clusters may act as an antiplasticizer, increasing the elastic modulus of the PEI matrix by 1.9 times. Therefore, a shifting of the β transition was observed at higher temperatures around the glass transition.

Effect of dichloromethane on methylmercury-induced cytotoxicity of rat C6 glioma cells

Effect of dichloromethane on methylmercury-induced cytotoxicity of rat C6 glioma cells

Dichloromethane as an inhibitor of cytochrome c oxidase in different tissues of rats

Based on the metabolism of dichloromethane (DCM) to carbon monoxide (CO), a process mediated by cytochrome P-4502E1 (CYP2E1), cytochrome c oxidase activity was determined in different tissues of rats after DCM exposure. It is likely that binding of CO to cytochrome c oxidase is significant at low carboxyhemoglobin levels, because intracellular effects of CO depend on CO partial pressures in the tissues. Two methods of exposure were used: (1) administration of DCM, 3.1, 6.2, and 12.4 mmol/kg p.o. in Oleum pedum tauri, 10% (v/v), producing a maximum of 10% COHb 6 h after gavage, and (2) accidental scenario, i.e. rats were exposed nose-only to DCM, 250,000 ppm for 20 s, producing 3-4% COHb after 2 h. Cytochrome c oxidase activity was reduced 6 h after the high oral DCM dose in brain, lung, and skeletal muscle by 28-42% and 20 min after inhalative uptake of DCM in the brain, liver, kidney, and skeletal muscle by 42-51%. COHb formation due to DCM, 6.2 mmol/kg p.o., was completely prevented after treatment of rats with the mechanism-based inhibitor of CYP2E1, diethyl-dithiocarbamate (DDTC), using an oral dose of 32 mumol/kg. The decrease in cytochrome c oxidase activity after exposure to DCM was not evident in rats treated with this dose of DDTC. Therefore, it seems that the effect of DCM is produced by the DCM metabolite CO.

ChemInform Abstract: The Role of Chlorine in the Partial Oxidation of Methane to Ethene on MgO Catalysts.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The role of chlorine in the partial oxidation of methane to ethene on MgO catalysts

The effect of dichloromethane on the activity and selectivity of an MgO catalyst in the methane coupling reaction has been investigated. The results indicate that the primary role of chlorine is to modify the surface of the catalyst so as to enhance the selectivity to ethane and ethene. The response of ethene and ethane to the introduction of dichloromethane is different, and this is taken as evidence that the dehydrogenation of ethane to ethene is not due to gas-phase reactions involving chlorine radicals. The physical properties of the catalyst before and after treatment with dichloromethane have been investigated using surface area measurements, X-ray diffraction and analytical transmission electron microscopy. Substantial changes in the morphology of the catalyst particles are observed but these do not account for the trends in catalytic properties. X-ray photoelectron spectroscopy has been used to determine the surface composition of the catalysts before and after treatment. Chlorine is observed in the treated catalyst at a surface concentration of 3%.

The effect of dichloromethane on the oxygenation of hemoglobin

Dichloromethane is an anesthetic that weakdy binds to hemoglobin at four different sites. It also reduces the gelation of hemoglobin S. Hemoglobin oxygenation curves have been measured for different partial pressures of dichloromethane. These curves show that the binding of oxygen to hemoglobin remains cooperative in the presence of dichloromethane. Application of the thermodynamic approach suggests that only one of the binding sites is responsible for decreasing the oxygen-affinity of hemoglobin.

Effect of dichloromethane on the sciatic motor conduction velocity of rats

There is a correlation between dichloromethane dosis (X) of 1--6 mmole/kg administered i.p. to rats and the sciatic motor conduction velocity (Y): Y = 57.1--1.091 X. The correlation coefficient 'r' is 0.437 (p less than 0.01). Presumably, the decrease of nerve conduction velocity is caused by the endogenous carbon monoxide production due to dichloromethane biotransformation.

Effect of dichloromethane on sickle cells. An [formula omitted] water proton magnetic resonance relaxation study

To examine the manner in which dichloromethane inhibits sickling, sickle blood was subjected to both prevention and reversal schemes over a range of CH 2Cl 2 vapor pressures. Following CH 2Cl 2-treatment, the rotating frame spin lattice relaxation time (T 1ϱ) of water protons in deoxygenated packed sickle cells was measured, cell types in a deoxygenated fixed sample were counted, and the extent of hemolysis determined. At CH 2Cl 2 vapor pressures above 200 mm, the NMR relaxation rate decreased sharply, the extent of hemolysis increased, the fraction of sickled cells and other abnormal erythrocytes decreased, and the fraction of biconcave discs increased. Apparently CH 2Cl 2 is absorbed by the cell membrane and preferentially lyses sickled cells and other abnormal cells. Part of the decrease in NMR relaxation rate with increased CH 2Cl 2 pressure is due to a larger fraction of discs, but an additional factor probably arises from CH 2Cl 2 inhibition of hemoglobin S gelation.

Effect of dichloromethane on hemoglobin function

Effect of dichloromethane on hemoglobin function

Stabilization of singlet ethoxycarbonylnitrene. Effect of dichloromethane on insertion into tetrahydrofuran and cyclohexane

Ratios of singlet ethoxycarbonylnitrene to total nitrene species for the insertion of the nitrene into tetrahydrofuran and cyclohexane in dichloromethane were determined by taking into consideration tetrahydrofuran–dichloromethane interactions, solvent polarity effects, and triplet quenching experiments. In the case of the nitrene generated photochemically, the rations were almost independent of dichloromethane concentration. This probably suggests that singlet destabilization by the external heavy atom effect of dichloromethane is counterbalanced by singlet stabilization due to an interaction between the nitrene and the lone pair electrons of dichloromethane. Whereas the result for the insertion of the nitrene generated thermally reveals slightly predominant singlet destabilization compared with the photochemical case. This may also result from different temperature conditions.

Effect of dichloromethane on the reaction of carbethoxynitrene with trans-1,2-dimethylcyclohexane

Effect of dichloromethane on the reaction of carbethoxynitrene with trans-1,2-dimethylcyclohexane

Corrosive effect of dichloromethane on metals

Corrosive effect of dichloromethane on metals