Dissociation constants of protonated methionine species in seawater media

Virender K. Sharma, Frank J Millero, Concetta De Stefano, Pasquale Crea

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The dissociation constants (pK 1 * and pK 2 *) for methionine have been measured in artificial seawater as a function of salinity (S = 5 to 35) and temperature (5 to 45 °C). The seawater pK 2 * values were lower than the values in NaCl at the same ionic strength while the pK 1 * values in seawater were lower only at S = 35. In an attempt to understand these differences, we have made measurements of the constants in Na-Mg-Cl solutions at 25 °C. The measured values have been used to determine the formation of Mg 2+ complexes and Pitzer interaction parameters for Mg 2+ with methionine. The seawater model with the interaction parameters accounts for the differences between the value of pK 1 * and pK 2 * between NaCl and seawater. This study demonstrates that it is important to consider all of the ionic interactions in natural waters when examining the dissociation of organic acids.

Original languageEnglish (US)
Pages (from-to)463-470
Number of pages8
JournalMarine Chemistry
Volume106
Issue number3-4
DOIs
StatePublished - Aug 2007

Fingerprint

Seawater
Methionine
seawater
Organic acids
Ionic strength
organic acid
salinity
Water
temperature
water
Temperature
parameter

Keywords

  • Dissociation constants
  • Methionine
  • Pitzer model
  • Salinity
  • Seawater
  • Thiols

ASJC Scopus subject areas

  • Chemistry(all)
  • Oceanography

Cite this

Dissociation constants of protonated methionine species in seawater media. / Sharma, Virender K.; Millero, Frank J; De Stefano, Concetta; Crea, Pasquale.

In: Marine Chemistry, Vol. 106, No. 3-4, 08.2007, p. 463-470.

Research output: Contribution to journalArticle

Sharma, VK, Millero, FJ, De Stefano, C & Crea, P 2007, 'Dissociation constants of protonated methionine species in seawater media', Marine Chemistry, vol. 106, no. 3-4, pp. 463-470. https://doi.org/10.1016/j.marchem.2007.04.008
Sharma, Virender K. ; Millero, Frank J ; De Stefano, Concetta ; Crea, Pasquale. / Dissociation constants of protonated methionine species in seawater media. In: Marine Chemistry. 2007 ; Vol. 106, No. 3-4. pp. 463-470.
@article{2377239470cf4a51aae6651319429869,
title = "Dissociation constants of protonated methionine species in seawater media",
abstract = "The dissociation constants (pK 1 * and pK 2 *) for methionine have been measured in artificial seawater as a function of salinity (S = 5 to 35) and temperature (5 to 45 °C). The seawater pK 2 * values were lower than the values in NaCl at the same ionic strength while the pK 1 * values in seawater were lower only at S = 35. In an attempt to understand these differences, we have made measurements of the constants in Na-Mg-Cl solutions at 25 °C. The measured values have been used to determine the formation of Mg 2+ complexes and Pitzer interaction parameters for Mg 2+ with methionine. The seawater model with the interaction parameters accounts for the differences between the value of pK 1 * and pK 2 * between NaCl and seawater. This study demonstrates that it is important to consider all of the ionic interactions in natural waters when examining the dissociation of organic acids.",
keywords = "Dissociation constants, Methionine, Pitzer model, Salinity, Seawater, Thiols",
author = "Sharma, {Virender K.} and Millero, {Frank J} and {De Stefano}, Concetta and Pasquale Crea",
year = "2007",
month = "8",
doi = "10.1016/j.marchem.2007.04.008",
language = "English (US)",
volume = "106",
pages = "463--470",
journal = "Marine Chemistry",
issn = "0304-4203",
publisher = "Elsevier",
number = "3-4",

}

TY - JOUR

T1 - Dissociation constants of protonated methionine species in seawater media

AU - Sharma, Virender K.

AU - Millero, Frank J

AU - De Stefano, Concetta

AU - Crea, Pasquale

PY - 2007/8

Y1 - 2007/8

N2 - The dissociation constants (pK 1 * and pK 2 *) for methionine have been measured in artificial seawater as a function of salinity (S = 5 to 35) and temperature (5 to 45 °C). The seawater pK 2 * values were lower than the values in NaCl at the same ionic strength while the pK 1 * values in seawater were lower only at S = 35. In an attempt to understand these differences, we have made measurements of the constants in Na-Mg-Cl solutions at 25 °C. The measured values have been used to determine the formation of Mg 2+ complexes and Pitzer interaction parameters for Mg 2+ with methionine. The seawater model with the interaction parameters accounts for the differences between the value of pK 1 * and pK 2 * between NaCl and seawater. This study demonstrates that it is important to consider all of the ionic interactions in natural waters when examining the dissociation of organic acids.

AB - The dissociation constants (pK 1 * and pK 2 *) for methionine have been measured in artificial seawater as a function of salinity (S = 5 to 35) and temperature (5 to 45 °C). The seawater pK 2 * values were lower than the values in NaCl at the same ionic strength while the pK 1 * values in seawater were lower only at S = 35. In an attempt to understand these differences, we have made measurements of the constants in Na-Mg-Cl solutions at 25 °C. The measured values have been used to determine the formation of Mg 2+ complexes and Pitzer interaction parameters for Mg 2+ with methionine. The seawater model with the interaction parameters accounts for the differences between the value of pK 1 * and pK 2 * between NaCl and seawater. This study demonstrates that it is important to consider all of the ionic interactions in natural waters when examining the dissociation of organic acids.

KW - Dissociation constants

KW - Methionine

KW - Pitzer model

KW - Salinity

KW - Seawater

KW - Thiols

UR - http://www.scopus.com/inward/record.url?scp=34547924090&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34547924090&partnerID=8YFLogxK

U2 - 10.1016/j.marchem.2007.04.008

DO - 10.1016/j.marchem.2007.04.008

M3 - Article

VL - 106

SP - 463

EP - 470

JO - Marine Chemistry

JF - Marine Chemistry

SN - 0304-4203

IS - 3-4

ER -