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Journal of Chromatography. A Mar 2015A novel method for the determination of the diffusion coefficient (D) of methanol in water and olive oil has been developed. Based on multiple headspace extraction gas...
A novel method for the determination of the diffusion coefficient (D) of methanol in water and olive oil has been developed. Based on multiple headspace extraction gas chromatography (MHE-GC), the methanol released from the liquid sample of interest in a closed sample vial was determined in a stepwise fashion. A theoretical model was derived to establish the relationship between the diffusion coefficient and the GC signals from MHE-GC measurements. The results showed that the present method has an excellent precision (RSD<1%) in the linear fitting procedure and good accuracy for the diffusion coefficients of methanol in both water and olive oil, when compared with data reported in the literature. The present method is simple and practical and can be a valuable tool for the determination of the diffusion coefficient of volatile analyte(s) into food simulants from food and beverage packaging material, both in research studies and in actual applications.
Topics: Chemistry Techniques, Analytical; Chromatography, Gas; Methanol; Olive Oil; Plant Oils; Water
PubMed: 25678320
DOI: 10.1016/j.chroma.2015.01.073 -
Regulatory Toxicology and Pharmacology... Jul 2014Due largely to the controversy concerning the potential human health effects from exposure to formaldehyde gas in conjunction with the misunderstanding of the... (Review)
Review
Due largely to the controversy concerning the potential human health effects from exposure to formaldehyde gas in conjunction with the misunderstanding of the well-established equilibrium relationship with its hydrated reaction product, methylene glycol, the concept of chemical equivalence between these two distinctly different chemicals has been adopted by regulatory authorities. Chemical equivalence implies not only that any concentration of methylene glycol under some condition of use would be nearly or completely converted into formaldehyde gas, but also that these two substances would be toxicologically equivalent as well. A relatively simple worst case experiment using 37% formalin (i.e., concentrated methylene glycol) dispels the concept of chemical equivalence and a review of relevant literature demonstrates that methylene glycol has no inherent toxicity apart from whatever concentration of formaldehyde that might be present in equilibrium with such solutions.
Topics: Formaldehyde; Humans; Methanol
PubMed: 24709515
DOI: 10.1016/j.yrtph.2014.03.007 -
International Archives of Occupational... Jul 1998Due to their transient nature, short-term exposures can be difficult to detect and quantify using conventional monitoring techniques. Biological monitoring may be...
Due to their transient nature, short-term exposures can be difficult to detect and quantify using conventional monitoring techniques. Biological monitoring may be capable of registering such exposures and may also be used to estimate important toxicological parameters. This paper investigates relationships between methanol concentrations in the blood, urine, and breath of volunteers exposed to methanol vapor at 800 ppm for periods of 0.5, 1, 2, and 8 h. The results indicate factors that must be considered for interpretation of the results of biological monitoring. For methanol, concentrations are not proportional to the exposure duration due to metabolic and other elimination processes that occur concurrently with the exposure. First-order clearance models can be used with blood, breath, or urine concentrations to estimate exposures if the time that has elapsed since the exposure and the model parameters are known. The 0.5 to 2-h periods of exposure were used to estimate the half-life of methanol. Blood data gave a half-life of 1.44+/-0.33 h. Comparable but slightly more variable results were obtained using urine data corrected for voiding time (1.55+/-0.67h) and breath data corrected for mucous membrane desorption (1.40+/-0.38 h). Methanol concentrations in blood lagged some 15-30 min behind the termination of exposure, and concentrations in urine were further delayed. Although breath sampling may be convenient, breath concentrations reflect end-expired or alveolar air only if subjects are in a methanol-free environment for 30 min or more after the exposure. At earlier times, breath concentrations included contributions from airway desorption or diffusion processes. As based on multicompartmental models, the desorption processes have half-lives ranging between 0.6 and 5 min. Preliminary estimates of the mucous membrane reservoir indicate contributions of under 10% for a 0.5-h exposure and smaller effects for longer periods of exposure.
Topics: Adult; Biomarkers; Breath Tests; Female; Humans; Inhalation Exposure; Male; Methanol; Middle Aged; Occupational Exposure; Time Factors
PubMed: 9749971
DOI: 10.1007/s004200050288 -
African Health Sciences Jun 2014Multi-resistantmicroorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida tropicalis e Candida krusei are the main causes of...
BACKGROUND
Multi-resistantmicroorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida tropicalis e Candida krusei are the main causes of microbial infections. Padina sanctae-crucis is a seaweed often used to check the contamination of ecosystems by materials such as heavy metals, but studies of the antimicrobial activity of the same seaweed were not found.
METHODS
The tests for the minimum inhibitory concentration and modulation of microbial resistance, with the use of ethanolic and methanolic extracts of Padina Sanctae-cruces combined with drugs of the class of aminoglycosides and antifungal were used to evaluate the activity against the cited microorganisms.
RESULTS
Was observed a modulation of antibiotic activity between the natural products and the E. coli and S. aureus strains, indicating a synergism and antagonism respectively.
CONCLUSIONS
The results showed a moderate modulatory effect against some microorganisms studied.
Topics: Anti-Bacterial Agents; Antifungal Agents; Bacteria; Ethanol; Fungi; Humans; Methanol; Microbial Sensitivity Tests; Phaeophyceae; Plant Extracts; Seaweed
PubMed: 25320586
DOI: 10.4314/ahs.v14i2.12 -
The New England Journal of Medicine Dec 1982
Topics: Adult; Ethanol; Female; Humans; Methanol; Suicide, Attempted
PubMed: 7144827
DOI: 10.1056/nejm198212093072423 -
Fundamental and Applied Toxicology :... Dec 1995Human exposure to methanol is likely to increase in the future due to its proposed use as an alternate automobile fuel. Since alcohols are known to esterify the fatty...
Human exposure to methanol is likely to increase in the future due to its proposed use as an alternate automobile fuel. Since alcohols are known to esterify the fatty acids in the body and some of those esterified esters are toxic, we studied the formation of fatty acid esters of methanol in Long-Evans male rats given a single oral dose of 3.5 g/kg body weight of methanol in saline. Animals given an equal volume of saline served as control. Three rats were euthanized at 1, 3, 6, 12 and 24 hr following the treatment. Fatty acid methyl esters, extracted from whole blood, liver, pancreas, and brown fat were separated by thin-layer chromatography and quantitated by gas chromatography (GC). Their identity was then confirmed by GC-mass spectrometry. Average levels as high as 596, 5293, 2239, 1106, 9665, 7728, 562, and 2792 micrograms/g (wet weight basis) of 14:0, 16:0, 16:1, 18:0, 18:1, 18:2, 18:3, and 20:4 fatty acid methyl esters, respectively, were found in the pancreas of methanol-treated rats. The average concentration of total fatty acid methyl esters was computed to be 4513, 29594, 22871, 18956, 17014, and 9702 micrograms/g in the pancreas compared to 1.9, 25.4, 36.8, 18.5, 18.9, and 14.2 micrograms/g in the liver at 0, 1, 3, 6, 12, and 24 hr, respectively, following methanol exposure. On dry lipid weight basis, the levels were significantly higher again in pancreas followed by brown fat and liver. In whole blood, only low levels of 16:0, 18:0, and 20:4 fatty acid methyl esters could be detected at all time points. The highest concentration of total fatty acid methyl esters in the pancreas, liver, and brown fat was detected at 1, 3, and 24 hr, respectively. Most of the fatty acid methyl esters found in the liver and pancreas decreased after 6 hr of methanol exposure. The fatty acid methyl esters of higher concentrations were 16:0 in the whole blood, 18:0, 18:1, 18:2, and 20:4 in liver, 18:1, and 18:2 in pancreas and 16:0, 18:1, and 18:2 in brown fat. These fatty acid methyl esters were also detected in the tissues of control rats indicating their endogenous formation. Significant increase in methylation of the fatty acids during methanol exposure, as found in this study, may serve as a defense mechanism for preventing available methanol from oxidative metabolism to render toxicity. However, the biological significance of these fatty acid methyl esters is yet to be understood.
Topics: Adipose Tissue, Brown; Administration, Oral; Animals; Chromatography, Gas; Esters; Fatty Acids; Gas Chromatography-Mass Spectrometry; Liver; Male; Methanol; Models, Biological; Pancreas; Rats
PubMed: 8835236
DOI: 10.1006/faat.1995.1167 -
Electrophoresis Sep 2019Affinity capillary electrophoresis (ACE) and pressure-assisted ACE were employed to study the noncovalent molecular interactions of antamanide (AA), cyclic decapeptide...
Affinity capillary electrophoresis (ACE) and pressure-assisted ACE were employed to study the noncovalent molecular interactions of antamanide (AA), cyclic decapeptide from the deadly poisonous fungus Amanita phalloides, with univalent (Li , Na , K , and NH ) and divalent (Mg and Ca ) cations in methanol. The strength of these interactions was quantified by the apparent stability constants of the appropriate AA-cation complexes. The stability constants were calculated using the nonlinear regression analysis of the dependence of the effective electrophoretic mobility of AA on the concentration of the above ions in the BGE (methanolic solution of 20 mM chloroacetic acid, 10 mM Tris, pH 7.8, containing 0-50 mM concentrations of the above ions added in the form of chlorides). Prior to stability constant calculation, the AA effective mobilities measured at actual temperature inside the capillary and at variable ionic strength of the BGEs were corrected to the values corresponding to the reference temperature of 25°C and to the constant ionic strength of 10 mM. From the above ions, sodium cation interacted with AA moderately strong with the stability constant 362 ± 16 L/mol. K , Mg , and Ca cations formed with AA weak complexes with stability constants in the range 37-31 L/mol decreasing in the order K > Ca > Mg . No interactions were observed between AA and small Li and large NH cations.
Topics: Cations; Drug Stability; Electrophoresis, Capillary; Methanol; Osmolar Concentration; Peptides, Cyclic
PubMed: 31054235
DOI: 10.1002/elps.201900043 -
Food Additives and Contaminants 1988Some distilled fruit spirits contain, normally, high quantities of methanol. After a brief summary of the process of methanol formation during fermentation and of the... (Comparative Study)
Comparative Study
Some distilled fruit spirits contain, normally, high quantities of methanol. After a brief summary of the process of methanol formation during fermentation and of the toxicological data, methanol concentrations of some distilled fruit spirits are indicated. Then, maximal amounts of methanol in spirits fixed by some countries are discussed as well as the problems which are generated by legislation.
Topics: Alcoholic Beverages; Fruit; Humans; Methanol
PubMed: 3396738
DOI: 10.1080/02652038809373713 -
Nordisk Medicin Nov 1947
Topics: Drug-Related Side Effects and Adverse Reactions; Methanol
PubMed: 18901622
DOI: No ID Found -
Journal of the American Chemical Society Nov 2011This communication demonstrates the homogeneous hydrogenation of CO(2) to CH(3)OH via cascade catalysis. Three different homogeneous catalysts, (PMe(3))(4)Ru(Cl)(OAc),...
This communication demonstrates the homogeneous hydrogenation of CO(2) to CH(3)OH via cascade catalysis. Three different homogeneous catalysts, (PMe(3))(4)Ru(Cl)(OAc), Sc(OTf)(3), and (PNN)Ru(CO)(H), operate in sequence to promote this transformation.
Topics: Carbon Dioxide; Catalysis; Hydrogenation; Methanol; Organometallic Compounds
PubMed: 22029268
DOI: 10.1021/ja208760j