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Frontiers in Public Health 2022Ingestion of methanol can result in severe irreversible morbidity, and death. Simple and easy methods to detect methanol and other hazardous additives prior to...
BACKGROUND
Ingestion of methanol can result in severe irreversible morbidity, and death. Simple and easy methods to detect methanol and other hazardous additives prior to consumption can prevent fatalities. This form of harm reduction is analogous to the widely practiced "pill testing" of recreational drugs in various countries. We aimed to evaluate the performance of two qualitative and quantitative kits to simultaneously identify the presence of methanol and formaldehyde in alcoholic beverages, and compare this to the standard gas chromatographic (GC) method.
METHODS
Two-hundred samples of Indian and Iranian alcoholic drinks were examined by two new qualitative and quantitative chemical kits designed based on a modified chromotropic acid (CA) method, as well as a gold standard GC method.
RESULTS
Methanol levels were similar when evaluated by GC and quantitative method ( = - 0.328, = 0.743). The 75th percentile of methanol level detection was 4,290 mg L (range; 0-83,132) using GC compared to that of 4,671 mg L (range; 0-84,960) using the qualitative kit (predefined color intensity reflecting the methanol/ethanol ratio). The quantitative kit was able to detect all methanol-contaminated and non-contaminated samples (110 and 60 cases, respectively: 100% sensitivity). In 25 samples, GC analysis showed no methanol; but the qualitative kit detected possible toxic substances. Formaldehyde measurement by UV/Vis analysis showed the presence of formaldehyde in 23 samples (92%) with a median 912 [IQR 249, 2,109; range 112-2,742] mg L.
CONCLUSION
Methanol and formaldehyde can be easily detected using these simple CA chemical kits. Qualitative positive results may indicate the risk of poisoning if the beverage is consumed. CA kits can be used in community setting by public health units and community organizations to monitor for methanol contamination and inform a public health response to reduce methanol-related harms to the public.
Topics: Harm Reduction; Iran; Alcoholic Beverages; Methanol; Formaldehyde
PubMed: 36408033
DOI: 10.3389/fpubh.2022.983663 -
European Biophysics Journal : EBJ Jan 2020Alamethicin is an antibiotic peptide comprising 20 amino acid residues and functions as an ion channel in biological membranes. Natural alamethicins have a variety of...
Alamethicin is an antibiotic peptide comprising 20 amino acid residues and functions as an ion channel in biological membranes. Natural alamethicins have a variety of amino acid sequences. Two of them, used as a mixed sample in this study, are: UPUAUAQUVUGLUPVUUQQO and UPUAUUQUVUGLUPVUUQQO, where U and O represent α-aminoisobutyric acid and phenylalaninol, respectively. As indicated, only the amino acid at position six differs, and the two alamethicins are referred to as alamethicin-A6 and -U6, respectively. The conformation and thermal stability of alamethicin-A6 and -U6 in methanol were examined using proton nuclear magnetic resonance (NMR) spectroscopy. Both alamethicins form an α-helix between the 2nd and 11th residues. The N-terminal, 19th and C-terminal residues take a non-helical conformation. The structure between the 12th and 18th residues has not been well determined due to the absence of cross peaks in the two-dimensional NMR data. The α-helices are maintained up to 54 °C at least. In contrast to these similarities, it has been found that the length of the α-helix of alamethicin-U6 is somewhat shorter than that of alamethicin-A6, the intra-molecular hydrogen bonds formed by the amide proton of the seventh residue is much more thermally stable for alamethicin-U6 than for alamethicin-A6, and the C-terminal residue of alamethicin-U6 has higher mobility than that of alamethicin-A6. The mobility of the N- and C-terminal residues is discussed on the basis of a model chain which consists of particles connected by rigid links, and the physiological significance of the mobility is emphasized.
Topics: Alamethicin; Hydrogen Bonding; Methanol; Molecular Dynamics Simulation; Protein Conformation; Protein Stability; Proton Magnetic Resonance Spectroscopy
PubMed: 31912177
DOI: 10.1007/s00249-019-01418-8 -
Current Issues in Molecular Biology 2017This review covers some recent advances in application of omics technologies to studying methylotrophs, with special reference to their activities in natural... (Review)
Review
This review covers some recent advances in application of omics technologies to studying methylotrophs, with special reference to their activities in natural environments. Some of the developments highlighted in this review are the new outlook at the role of the XoxF-type, lanthanum-dependent methanol dehydrogenase in natural habitats, new mechanistic details of methane oxidation through the reverse methanogenesis pathway, propensity of 'aerobic' methanotrophs to thrive in hypoxic environments and potential connection of this process to denitrification, and a novel outlook at methane oxidation as a community function.
Topics: Aerobiosis; Anaerobiosis; Bacteria; Metabolomics; Metagenomics; Methane; Methanol; Microbial Consortia; Proteomics
PubMed: 28686571
DOI: 10.21775/cimb.024.119 -
The Journal of Physical Chemistry. A Aug 2022The gas-phase sequential association of methanol onto protonated benzonitrile (CHCNH) and the proton-bound dimer (CHCN)H have been examined experimentally by equilibrium...
The gas-phase sequential association of methanol onto protonated benzonitrile (CHCNH) and the proton-bound dimer (CHCN)H have been examined experimentally by equilibrium thermochemical measurements and computationally by density functional theory (DFT). The bonding enthalpy (Δ°) for the association of methanol with protonated benzonitrile (25.2 kcal mol) reflects the strong electrostatic interaction provided by the formation of an ionic hydrogen bond in the CHCNHOHCH cluster in excellent agreement with a DFT-calculated binding energy of 24.9 kcal mol. The sequential bonding enthalpy within the (CHCN)H(OHCH) clusters decreases from 25.2 to 10.6 kcal mol for the eighth solvation step ( = 8), which remains more than 25% above the enthalpy of vaporization of liquid methanol (8.4 kcal mol). The nonbulk convergence of Δ° with eight solvent molecules is attributed to the external solvation of a benzonitrile molecule by an extended hydrogen bonding network of protonated methanol clusters H(CHOH). In the external solvation of protonated benzonitrile by methanol, the proton resides on the methanol subcluster and the neutral benzonitrile molecule remains outside and bonded to the surface of the protonated methanol cluster. The bonding enthalpy of methanol to the proton-bound benzonitrile dimer (CHCN)H(NCCH) is measured to be 18.0 kcal mol, in good agreement with a DFT-calculated value of 17.1 kcal mol, which reflects the association of the proton with the lower proton affinity methanol molecule, thus forming a highly stable structure of protonated methanol terminated by two ionic hydrogen bonds to the two benzonitrile molecules. The external solvation of benzonitrile by methanol ices in space allows benzonitrile to remain on the ice grain surface rather than being isolated inside the ice. This could provide accessibility for reactions with incoming ions and molecules or for photochemical processes by UV irradiation, leading to the formation of complex organics on the surface of ice grains.
Topics: Hydrogen; Hydrogen Bonding; Methanol; Nitriles; Protons; Thermodynamics
PubMed: 35917155
DOI: 10.1021/acs.jpca.2c03715 -
Analytical Methods : Advancing Methods... Dec 2022The selection of an appropriate solvent system is the most crucial step in high-speed countercurrent chromatography (HSCCC) separation. The compound polarity plays an...
The selection of an appropriate solvent system is the most crucial step in high-speed countercurrent chromatography (HSCCC) separation. The compound polarity plays an important role in HPLC analysis and HSCCC separation, and it can be calculated by the HPLC polarity parameter model and the average polarity of the HSCCC solvent system, respectively. However, flow rates, columns and methanol concentrations of the HPLC experiment can influence the calculation of the compound polarity. Therefore, the applicability and accuracy of the HPLC polarity parameter model still needed to be extensively validated. We chose 14 compounds to conduct the shake-flask experiments and HPLC analysis on, such as apigenin, honokiol, phloridzin and dihydromyricetin. The HPLC analysis results showed that different flow rates and columns have negligible effects on the calculated compound polarities. However, there was a certain variation trend in the calculated polarities with different methanol concentrations. Although the polarity values of some compounds showed a difference between the HPLC analysis and shake-flask experiments, their partition coefficients () in the HSCCC solvent systems were still located in the range of 0.5 < < 2.0. Guided by the HPLC polarity parameter model, the appropriate HSCCC solvent systems for mangosteen peel and Hance were selected, and the two main components (mangostin and quercetin) were isolated from their extracts, respectively. The separation results showed that the predicted compound polarities were sufficient to meet the HSCCC separation requirements. Meanwhile, this method required only 1 to 2 HPLC analyses with reference compounds, greatly improved the efficiency of the HSCCC solvent system selection, and shortened the experimental time. The polarity parameter model was a fast and efficient analysis method for the selection of an appropriate HSCCC solvent system.
Topics: Countercurrent Distribution; Chromatography, High Pressure Liquid; Solvents; Methanol; Hypericum
PubMed: 36383038
DOI: 10.1039/d2ay01377k -
Molecules (Basel, Switzerland) Dec 2022In this study, the methanolic and infusion extracts of two species, and subsp. , were tested for their chemical composition and biological abilities (antioxidant,...
In this study, the methanolic and infusion extracts of two species, and subsp. , were tested for their chemical composition and biological abilities (antioxidant, enzyme inhibitory and anti-inflammatory effects). The extracts yielded total phenolic and flavonoid contents in the range of 83.43-127.52 mg GAE/g and 9.41-46.34 mg RE/g, respectively. HPLC analysis revealed rosmarinic acid to be a major component of the studied extracts (15.85-26.43%). The best ABTS radical scavenging ability was observed in the methanol extract of with 379.11 mg TE/g, followed by in the methanol extract of (360.93 mg TE/g). In the CUPRAC assay, the highest reducing ability was also found in the methanol extract of with 802.22 mg TE/g. The phosphomolybdenum ability ranged from 2.39 to 3.61 mmol TE/g. In terms of tyrosinase inhibitory effects, the tested methanol extracts (83.18-89.66 mg KAE/g) were higher than the tested water extracts (18.74-19.11 mg KAE/g). Regarding the BChE inhibitory effects, the methanol extracts were active on the enzyme while the water extracts showed no inhibitory effect on it. Overall, the methanolic extracts showed better enzyme inhibition compared to the infusion extracts. Molecular docking also showed the selected exhibited potential binding affinities with all enzymes, with a preference for cholinesterases. Additionally, the extracts were effective in attenuating the LPS-induced increase in COX-2 and IL-6 gene expression in isolated colon, thus indicating promising anti-inflammatory effects. The preliminary results of this study suggest that these species are good natural sources of antioxidants and also provide some scope as enzyme inhibitors, most likely due to their bioactive contents such as phenolic acids, and thus can be exploited for different applications related to health promotion and disease prevention.
Topics: Lamiaceae; Molecular Docking Simulation; Methanol; Plant Extracts; Antioxidants; Thymus Plant; Water; Anti-Inflammatory Agents
PubMed: 36558163
DOI: 10.3390/molecules27249029 -
Journal of Analytical Toxicology 2015A simple, cost-effective headspace gas chromatography (GC) method coupled with GC with flame ionization detection for simultaneous determination of methanol, ethanol and...
A simple, cost-effective headspace gas chromatography (GC) method coupled with GC with flame ionization detection for simultaneous determination of methanol, ethanol and formic acid was developed and validated for clinical and toxicological purposes. Formic acid was derivatized with an excess of isopropanol under acidic conditions to its volatile isopropyl ester while methanol and ethanol remained unchanged. The entire sample preparation procedure is complete within 6 min. The design of the experiment (the face-centered central composite design) was used for finding the optimal conditions for derivatization, headspace sampling and chromatographic separation. The calibration dependences of the method were quadratic in the range from 50 to 5,000 mg/L, with adequate accuracy (89.0-114.4%) and precision (<12%) in the serum. The new method was successfully used for determination of selected analytes in serum samples of intoxicated patients from among those affected by massive methanol poisonings in the Czech Republic in 2012.
Topics: Calibration; Chromatography, Gas; Ethanol; Female; Flame Ionization; Formates; Humans; Male; Methanol
PubMed: 26178163
DOI: 10.1093/jat/bkv075 -
Soudni Lekarstvi 2019A fatal case of abuse of solvent containing mixture of toluene and methanol is presented. Concentrations of toluene, methanol and formic acid in a femoral venous blood...
A fatal case of abuse of solvent containing mixture of toluene and methanol is presented. Concentrations of toluene, methanol and formic acid in a femoral venous blood sample were 20.1 mg/L, 210 mg/L and 25.2 mg/L, respectively. From the autopsy findings and toxicological examination, we concluded that the cause of death was poisoning by toluene and methanol.
Topics: Autopsy; Formates; Humans; Methanol; Solvents; Substance-Related Disorders; Toluene
PubMed: 31726838
DOI: No ID Found -
Analytical Cellular Pathology... 2016Many studies have reported that methanol toxicity to primates is mainly associated with its metabolites, formaldehyde (FA) and formic acid. While methanol metabolism and...
Many studies have reported that methanol toxicity to primates is mainly associated with its metabolites, formaldehyde (FA) and formic acid. While methanol metabolism and toxicology have been best studied in peripheral organs, little study has focused on the brain and no study has reported experimental evidence that demonstrates transformation of methanol into FA in the primate brain. In this study, three rhesus macaques were given a single intracerebroventricular injection of methanol to investigate whether a metabolic process of methanol to FA occurs in nonhuman primate brain. Levels of FA in cerebrospinal fluid (CSF) were then assessed at different time points. A significant increase of FA levels was found at the 18th hour following a methanol injection. Moreover, the FA level returned to a normal physiological level at the 30th hour after the injection. These findings provide direct evidence that methanol is oxidized to FA in nonhuman primate brain and that a portion of the FA generated is released out of the brain cells. This study suggests that FA is produced from methanol metabolic processes in the nonhuman primate brain and that FA may play a significant role in methanol neurotoxicology.
Topics: Animals; Brain; Formaldehyde; Injections, Intraventricular; Macaca mulatta; Male; Methanol; Oxidation-Reduction; Time Factors
PubMed: 27066393
DOI: 10.1155/2016/4598454 -
Bioresource Technology Oct 2023In this paper, the plate-heat transfer type bio-methanol steam reforming reactor for hydrogen fuel cell vehicles and its operation performance was studied. The structure...
In this paper, the plate-heat transfer type bio-methanol steam reforming reactor for hydrogen fuel cell vehicles and its operation performance was studied. The structure of the plate-heat transfer type for bio-methanol reforming has been designed and optimized with the application parameters of hydrogen production capacity, hydrogen production rate, bio-methanol conversion rate, volume limitation. Results showed the catalyst particle size has little influence when it less than 0.85 mm; However, when the catalyst loading was 20 g and the feed rate of bio-methanol solution was 1.5 mL/min, the effect of reforming bio-methanol was the best. At this time, the specific hydrogen production was 64.062 mL/g.min, the hydrogen production rate was 21.354 mL/s, the bio-methanol conversion rate was 82.25%. This paper can provide scientific reference for further research and development of high-efficiency and low-cost bio-methanol reforming hydrogen production equipment.
Topics: Methanol; Hot Temperature; Hydrogen; Steam; Catalysis
PubMed: 37473786
DOI: 10.1016/j.biortech.2023.129509