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Spectrochimica Acta. Part A, Molecular... May 2013The (tetrazol-5-yl)acetic acid crystal was characterized by the X-ray diffraction and FTIR spectroscopic methods. The analysis of the crystal structure reveals that the...
The (tetrazol-5-yl)acetic acid crystal was characterized by the X-ray diffraction and FTIR spectroscopic methods. The analysis of the crystal structure reveals that the compound exists in the solid state as 1H-tautomer. The molecules are linked by two types of the intermolecular hydrogen bonds forming an infinite two-dimensional network in the (101) plane. Intramolecular N-H···O hydrogen bonds are also formed in the crystal. The analysis of the FTIR spectra of the crystalline sample and its deuterated analogue, based on the B3LYP/6-311++G(2d,2p) frequency calculations of two model tetramers, has been performed in relation to the obtained crystal structure data.
Topics: Acetates; Acetic Acid; Crystallography, X-Ray; Hydrogen Bonding; Molecular Conformation; Spectrophotometry, Infrared; Tetrazoles; Vibration
PubMed: 23474482
DOI: 10.1016/j.saa.2013.01.086 -
Rapid Communications in Mass... Dec 2015Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/pyrolysis-gas chromatography/combustion-isotope ratio mass spectrometry...
RATIONALE
Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography/pyrolysis-gas chromatography/combustion-isotope ratio mass spectrometry (GC/Py-GC/C-IRMS) was developed for the simultaneous determination of the intramolecular and molecular carbon-isotopic composition (δ(13) C value) of acetic acid.
METHODS
The δ(13) C values of carboxyl and methyl carbon were standardized using calibration curves constructed from the regression between the measured δ(13) C values and the δ(13) C values of working standards determined in a previous study. We applied this developed HS-SPME-GC/Py-GC/C-IRMS technique to commercial vinegars.
RESULTS
In one injection analysis, the bulk and intramolecular δ(13) C values of pure acetic acid standards can be obtained. The repeatability (1σ) of the bulk δ(13) C values is within ±0.4‰, and that of the δ(13) Ccarboxyl and δ(13) Cmethyl values is within ±0.6‰. The intramolecular δ(13) C values of acetic acid in vinegars exhibit a similar pattern. The average Δδ value (δ(13) CCOOH - δ(13) CCH3 ) is 4.3 ± 2.0‰.
CONCLUSIONS
The approach presented herein for the molecular and intramolecular δ(13) C determination of acetic acid avoids switching between configuration systems and thereby reduces systematic errors. It is expected to be useful for examining isotope fractionation associated with processes related to organic acid (bio)transformations.
Topics: Acetic Acid; Carbon Isotopes; Food Analysis; Gas Chromatography-Mass Spectrometry; Reproducibility of Results; Solid Phase Microextraction
PubMed: 26563704
DOI: 10.1002/rcm.7398 -
Isolation and characterization of a gas-producing and acid-resistant bacterium from spoiled vinegar.International Journal of Food... Jun 2023To understand the deterioration of vinegar that has frequently occurred in China recently and to address such a concern, the physicochemical indicators and bacterial...
To understand the deterioration of vinegar that has frequently occurred in China recently and to address such a concern, the physicochemical indicators and bacterial structure of the spoiled vinegar collected from Sichuan were preliminarily investigated. Results showed that Lactobacillaceae was most likely responsible for the decrease of vinegar total sugar and furfural, through which total acid and furfuryl alcohol were generated. Then, an unreported difficult-to-cultivate gas-producing bacterium named Z-1 was isolated using a modified MRS medium. Strain Z-1 was identified as Acetilactobacillus jinshanensis subsp. aerogenes on the basis of physiological, biochemical, molecular biological and whole genome analyses. According to the investigation, such species was present throughout the fermentation process and not limited in Sichuan. The analysis of genetic diversity indicated that all the obtained A. jinshanensis isolates displayed high sequence similarity and an absence of recombination. Although it demonstrated acid resistance, Z-1 could be completely deactivated through heating (60 °C). Based on the above results, suggestions for safe production are made for vinegar enterprises.
Topics: Acetic Acid; Bacteria; Fermentation; Lactobacillaceae; China
PubMed: 36913840
DOI: 10.1016/j.ijfoodmicro.2023.110167 -
Archives of Dermatology Sep 1992
Topics: Acetates; Acetic Acid; Humans; Iatrogenic Disease; Male; Penis; Skin Diseases
PubMed: 1519951
DOI: No ID Found -
Canadian Journal of Chemistry Jun 1951
Topics: Acetates; Acetic Acid; Electrolytes; Freezing; Nitric Acid; Transition Temperature
PubMed: 14848749
DOI: 10.1139/v51-054 -
Journal of Bacteriology Sep 1947
Topics: Acetates; Acetic Acid; Butyrates; Butyric Acid; Clostridium; Fermentation; Lactic Acid
PubMed: 16561372
DOI: 10.1128/jb.54.3.381-391.1947 -
Journal of Bacteriology Dec 1953
Topics: Acetates; Acetic Acid; Acetobacter; Bacteria; Ethanol
PubMed: 13117785
DOI: 10.1128/jb.66.6.634-638.1953 -
The Tohoku Journal of Experimental... Sep 1950
Topics: Acetates; Acetic Acid; Amino Acids; Hydrochloric Acid; Proteins
PubMed: 14809727
DOI: 10.1620/tjem.52.283 -
Journal of Biotechnology Aug 2002Methods of adapting micro-organisms to an inhibiting factor in an active industrial bioprocess were examined with an acetic acid fermentation as model. With the aim of... (Comparative Study)
Comparative Study
Methods of adapting micro-organisms to an inhibiting factor in an active industrial bioprocess were examined with an acetic acid fermentation as model. With the aim of automatic control, a fuzzy-logic system was developed on the basis of the collected knowledge of skilled vinegar brewers. In a first step, this fuzzy system was to assess the actual adaptation degree of the bacteria on the basis of data from robust and reasonably priced sensors. From this information an appropriate setpoint value for the inhibiting factor 'final acid concentration' was derived for each batch cycle. As a result a further acid tolerance was found after several batch cycles. This adaptation effect should be used to increase the product concentration to more than 20 g per 100 ml acetic acid with a high productivity. The stepwise adapted culture was productive over the aimed acetic acid concentration, a 10% improvement of the product formation rate could be found compared with the status before conditioning. High product concentration and increased productivity finally result in shorter cycle times, less transport and storage volumes, an improved utilization of energy and material resources, and, last but not least, they are an essential steps towards the fulfillment of economical and ecological demands.
Topics: Acetic Acid; Acetobacter; Algorithms; Bioreactors; Expert Systems; Feedback; Fermentation; Fuzzy Logic; Industrial Microbiology; Pilot Projects; Quality Control; Reproducibility of Results; Sensitivity and Specificity
PubMed: 12067520
DOI: 10.1016/s0168-1656(02)00065-2 -
Journal of the American Chemical Society Oct 1947
Topics: Acetates; Acetic Acid; Halogenation; Ketosteroids; Solvents
PubMed: 20268298
DOI: 10.1021/ja01202a048