Semi-mechanistic Partial Buffer Approach to Modeling pH, the Buffer Properties, and the Distribution of Ionic Species in Complex Solutions

Dougherty, Daniel P.; Neta, E.R.D.; McFeeters, Roger F.; Lubkin, Sharon R.; Breidt, Fred

doi:10.1021/jf0531508

Cited by 20 publications

(18 citation statements)

References 12 publications

(23 reference statements)

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“…All acid solutions contained 20 mM D-gluconic acid sodium salt (Sigma), which functioned as a noninhibitory buffer (pKa ϭ 3.8) (7). The ionic strength of the acid solutions (0.342, 0.684, or 1.027) was held constant by using NaCl; they were designed using pHTools software (22), a custom MATLAB routine. Additionally, the pH of the acetic acid solutions was held constant at pH 3.2 by the addition of HCl or NaOH.…”

Section: Methodsmentioning

confidence: 99%

Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7

Hosein

Breidt

Smith

2011

Appl Environ Microbiol

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Microbiological safety has been a critical issue for acid and acidified foods since it became clear that acid-tolerant pathogens such as Escherichia coli O157:H7 can survive (even though they are unable to grow) in a pH range of 3 to 4, which is typical for these classes of food products. The primary antimicrobial compounds in these products are acetic acid and NaCl, which can alter the intracellular physiology of E. coli O157:H7, leading to cell death. For combinations of acetic acid and NaCl at pH 3.2 (a pH value typical for non-heatprocessed acidified vegetables), survival curves were described by using a Weibull model. The data revealed a protective effect of NaCl concentration on cell survival for selected acetic acid concentrations. The intracellular pH of an E. coli O157:H7 strain exposed to acetic acid concentrations of up to 40 mM and NaCl concentrations between 2 and 4% was determined. A reduction in the intracellular pH was observed for increasing acetic acid concentrations with an external pH of 3.2. Comparing intracellular pH with Weibull model predictions showed that decreases in intracellular pH were significantly correlated with the corresponding times required to achieve a 5-log reduction in the number of bacteria.

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Section: Methodsmentioning

confidence: 99%

Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7

Hosein

Breidt

Smith

2011

Appl Environ Microbiol

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“…The ion buffer capacity of heterogeneous (twophase) systems has been studied relatively well only for the pH buffers (Pfendt 1995; Dougherty et al 2006), partly because slow reactions make experimental studies difficult, partly because of the mathematical complexity of the theoretical calculations. Most pertinent to the research proposed here is our own result (Fishtik and Povar 2006;Povar 1995, a, Povar 1996b, c, 2000aLuca 2003, Povar andSpînu 2014e).…”

Section: Heterogeneous (Two-phase) Ion Buffer Systemsmentioning

confidence: 99%

Application of the buffer theory for evaluating attenuation and natural remediation of ionic pollutants in aquatic ecosystems

Povar

Spînu

2015

Ecol Process

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The main focus in this review is showing how to use the developed buffer theory for assessing and predicting the long-term phenomena of attenuation and natural remediation of ionic pollutants in contaminated aquatic ecosystems, as well as for analyzing the way by which metals move and transform within the environment, the distribution of metals in ecosystems, their deposition and cycling in the terrestrial environment. The buffer theory is based on the rigorous thermodynamic analysis of complex chemical equilibria under environmental conditions in aquatic ecosystems, as natural waters and soils. It has been established that both homogeneous and heterogeneous systems manifest a buffer action towards all their components. The buffer properties in relation to the solid phase components are amplified with an increase of solubility due to protolytic or complex formation equilibria in saturated solutions. It has been established that the buffer capacities of components are mutually proportional, whereas for heterogeneous systems these relationships depend on the stoichiometric composition of solid phases. The use of the developed buffer approach may yield extended knowledge and a deeper understanding of the processes that control the concentrations of components. A number of the important conclusions concerning the investigated buffer systems have been made. The obtained results are indented to provide researchers with a tool needed to help them to set reliable limits of ion (metal) levels in the environment.

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“…General theory devoted to calculation of pH and distribution of species in particular buffer mixtures can be found in [20,[67][68][69][70]. Chemical formulation includes a number of the mass-action equations linked with the mass and charge conservation equations.…”

Section: Citrate Buffersmentioning

confidence: 99%

Dissociation Equilibria in Solutions with Citrate Ions

Apelblat

2014

Citric Acid

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Semi-mechanistic Partial Buffer Approach to Modeling pH, the Buffer Properties, and the Distribution of Ionic Species in Complex Solutions

Cited by 20 publications

References 12 publications

Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7

Modeling the Effects of Sodium Chloride, Acetic Acid, and Intracellular pH on Survival of Escherichia coli O157:H7

Application of the buffer theory for evaluating attenuation and natural remediation of ionic pollutants in aquatic ecosystems

Dissociation Equilibria in Solutions with Citrate Ions

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