scholarly journals General Analytical Procedure for Determination of Acidity Parameters of Weak Acids and Bases

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Bogusław Pilarski ◽  
Roman Kaliszan ◽  
Dariusz Wyrzykowski ◽  
Janusz Młodzianowski ◽  
Agata Balińska
Keyword(s):  
Organic Acids ◽  
Excellent Agreement ◽  
Analytical Procedure ◽  
Water Solution ◽  
Weak Acids ◽  
Weak Organic Acids ◽  
General Methodology ◽  
Acids And Bases

The paper presents a new convenient, inexpensive, and reagent-saving general methodology for the determination ofpKavalues for components of the mixture of diverse chemical classes weak organic acids and bases in water solution, without the need to separate individual analytes. The data obtained from simple pH-metric microtitrations are numerically processed into reliablepKavalues for each component of the mixture. Excellent agreement has been obtained between the determinedpKavalues and the reference literature data for compounds studied.

scholarly journals Determination of liposome/water partition coefficients of organic acids and bases by solid-phase microextraction

The Analyst ◽  
2001 ◽  
Vol 127 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Beate I. Escher ◽  
Michael Berg ◽  
Jürg Mühlemann ◽  
Martin A. A. Schwarz ◽  
Joop L. M. Hermens ◽  
...  
Keyword(s):  
Organic Acids ◽  
Partition Coefficients ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Acids And Bases

scholarly journals Quantitative Analysis of the Modes of Growth Inhibition by Weak Organic Acids in Saccharomyces cerevisiae

2012 ◽  
Vol 78 (23) ◽  
pp. 8377-8387 ◽  
Author(s):  
Azmat Ullah ◽  
Rick Orij ◽  
Stanley Brul ◽  
Gertien J. Smits
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Organic Acids ◽  
Growth Inhibition ◽  
Organic Anion ◽  
Acid Stress ◽  
Yeast Cells ◽  
Plasma Membrane Atpase ◽  
Weak Acids ◽  
Content Type ◽  
Weak Organic Acids

ABSTRACTWeak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pHi) inSaccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pHi, was a determinant for growth inhibition. This pHirecovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pHi, and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pHiupon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport.

Critical examination of the methods employed in silage analysis, with observations on some special chemical characteristics of “sour” silage

1925 ◽  
Vol 15 (3) ◽  
pp. 343-357 ◽  
Author(s):  
Herbert Ernest Woodman
Keyword(s):  
Organic Acids ◽  
Dry Matter ◽  
Analytical Procedure ◽  
Ammonium Salts ◽  
Critical Examination ◽  
Chemical Characteristics ◽  
General Application ◽  
Salts Of Organic Acids ◽  
Lactic Acids

A résumé of the analytical methods hitherto employed for the chemical investigation of samples of silage has been given. It has been shown that these methods fail to yield trustworthy results when applied to the analysis of “sour” silage, owing to the disturbing effect of the presence of appreciable amounts of ammonium salts of organic acids in this type of silage.Investigations have been made into the behaviour of the ammonium salts of acetic, butyric and lactic acids, when solutions of these substances, in the presence and absence of the free organic acids, are (1) submitted to distillation in steam, (2) evaporated in the steam oven under conditions comparable with those obtaining during the determination of the dry matter of silage. The bearing of these results on the problem of silage analysis has been discussed.A modified analytical procedure for silage investigations has been devised which is capable of general application.

Thin-layer chromatographic determination of the pKavalues of organic acids and bases

2005 ◽  
Vol 18 (104) ◽  
pp. 323-325 ◽  
Author(s):  
Bozena Tyman-Szram ◽  
Robert Musiol ◽  
Mieczyslaw Sajewicz ◽  
Jaroslaw Polanski
Keyword(s):  
Organic Acids ◽  
Thin Layer ◽  
Chromatographic Determination ◽  
Acids And Bases
Sign in / Sign up

Export Citation Format

Share Document