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Rapid Communications in Mass... Aug 2014Methanol, ethanol, and acetic acid are not easily extracted from aqueous samples and are susceptible to isotope fractionation in gas chromatography/isotope ratio mass...
RATIONALE
Methanol, ethanol, and acetic acid are not easily extracted from aqueous samples and are susceptible to isotope fractionation in gas chromatography/isotope ratio mass spectrometry (GC/IRMS) analysis. Developing a direct dilution GC/IRMS method for aqueous samples, by adjusting the sample concentrations in common solvents to be similar to each other and using a fixed GC split ratio, is very convenient and important because any linearity effects caused by amount-dependent isotope fractionation can be avoided.
METHODS
The suitability of acetonitrile and acetone solvents for the GC/IRMS analysis of pure methanol, ethanol and acetic acid, and commercial liquor and vinegar samples was evaluated using n-hexane and water as control solvents. All the solvents including water were separated from the analyte on a HP-INNOWAX column and were diverted away from the combustion interface. The influence of liquor matrix on the ethanol GC/IRMS analyses was evaluated by adding pure ethanol to liquor samples.
RESULTS
Acetonitrile and acetone gave similar δ(13) C values for pure ethanol and pure acetic acid to those obtained in water and n-hexane, and also gave similar δ(13) C values of ethanol in liquor and acetic acid in white vinegar to that obtained in water. For methanol analysis, acetonitrile and refined acetone gave similar δ(13) C values to that obtained in water, but n-hexane was not a suitable solvent. In addition, isotopic fractionation caused by solvent and solute interactions was observed.
CONCLUSIONS
We recommend using acetonitrile for the GC/IRMS analysis of aqueous alcoholic samples, and acetone for the analysis of aqueous acetic acid samples. This direct dilution method can provide high accurate and precise GC/IRMS analysis of the relative changes in δ(13) C values of methanol, ethanol, and acetic acid.
Topics: Acetic Acid; Ethanol; Flow Injection Analysis; Gas Chromatography-Mass Spectrometry; Liquid-Liquid Extraction; Methanol; Solvents
PubMed: 24975247
DOI: 10.1002/rcm.6948 -
Journal of Bacteriology Apr 1950
Topics: Acetates; Acetic Acid; Bacteria; Enterobacter aerogenes; Escherichia coli; Oxidation-Reduction
PubMed: 15436423
DOI: 10.1128/jb.59.4.499-507.1950 -
Journal of Hazardous Materials Apr 2006A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate...
A simultaneous conductometric titration method for determination of mixtures of acetic acid, monochloroacetic acid and trichloroacetic acid based on the multivariate calibration partial least squares is proposed. It is possible to obtain an adjustable model to relate squared concentration values of the mixtures used in the calibration range by conductance. The effect of orthogonal signal correction (OSC) as a preprocessing technique used to remove the information unrelated to the target variables is studied. The calibration model was build using conductometric titrations data of 16 mixtures of three acids. The concentration matrix was designed by a orthogonal design. The root mean squares error of prediction (RMSEP) for acetic acid, monochloroacetic acid and trichloroacetic acid with and without OSC were 0.08, 0.30 and 0.08, and 0.15, 0.40 and 0.18, respectively. The results obtained by OSC-PLS are better than the PLS and this indicate the successful application of the OSC filter as a good preprocessing method in multivariate calibration methods. The proposed procedure allows the simultaneous determination of these acids, in the synthetic mixtures.
Topics: Acetates; Acetic Acid; Calibration; Least-Squares Analysis; Models, Theoretical; Spectrophotometry; Trichloroacetic Acid
PubMed: 16236436
DOI: 10.1016/j.jhazmat.2005.09.016 -
Nature Oct 1947
Topics: Acetates; Acetic Acid; Aspergillus; Aspergillus flavus; Glucose; Niger
PubMed: 20269864
DOI: 10.1038/160573a0 -
A.M.A. American Journal of Diseases of... May 1952
Topics: Acetates; Acetic Acid; Aerosols; Bronchiectasis; Humans; Pseudomonas Infections; Pseudomonas aeruginosa
PubMed: 14914162
DOI: 10.1001/archpedi.1952.02040090083008 -
The Physical Therapy Review Feb 1955
Topics: Acetates; Acetic Acid; Disease; Humans; Muscles; Muscular Diseases; Shoulder; Tendinopathy; Tendons
PubMed: 13236513
DOI: 10.1093/ptj/35.2.84 -
The Journal of Biological Chemistry 1945
Topics: Acetates; Acetic Acid; Fatty Acids
PubMed: 21004549
DOI: No ID Found -
Applied Microbiology Sep 1958
Topics: Acetates; Acetic Acid; Bacteria; Carbohydrates; Lactic Acid
PubMed: 13571971
DOI: 10.1128/am.6.5.316-318.1958 -
The Journal of Biological Chemistry Mar 1951
Topics: Acetates; Acetic Acid; Amino Acids; Candida; Saccharomyces cerevisiae; Yeasts
PubMed: 14832221
DOI: No ID Found -
The Journal of Biological Chemistry Jun 1950
Topics: Acetates; Acetic Acid; Heme; Hemoglobins
PubMed: 15428460
DOI: No ID Found