Get access

Interference by Nitrous Acid Decomposition in the Kinetic Study of Nitrosation Reactions

Authors

  • Jorge Arenas-Valgañón,

    1. Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008 Salamanca, Spain
    Search for more papers by this author
  • Rafael Gómez-Bombarelli,

    1. Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008 Salamanca, Spain
    Current affiliation:
    1. Department of Physics, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
    Search for more papers by this author
  • Marina González-Pérez,

    1. Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008 Salamanca, Spain
    Search for more papers by this author
  • Mario González-Jiménez,

    1. Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008 Salamanca, Spain
    Search for more papers by this author
  • Emilio Calle,

    1. Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008 Salamanca, Spain
    Search for more papers by this author
  • Julio Casado

    Corresponding author
    1. Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008 Salamanca, Spain
    Search for more papers by this author

  • Contract grant sponsor: Spanish Ministerio de Economía y Competitividad.

  • Contract grant sponsor: FEDER Fund (Fondo Europeo de Desarrollo Regional).

  • Contract grant number: CTQ2010-18999.

ABSTRACT

Under the acidic conditions of the stomach lumen, nitrosation reactions can occur in the human body between nitrite (added to meat because of its antibotulinic properties) and many compounds such as amino acids. From the results obtained, two conclusions can be drawn: (i) In the quantitative study of nitrosation reactions, it is necessary to take into account the competing reaction of HNO2 decomposition, which in some conditions is the dominant reaction; (ii) two alternative approaches based on the initial rate method are necessary to assess the weight of nitrous acid decomposition using taurine and homotaurine as nitrosatable substrates. In strongly acidic media, the decomposition reaction is dominant: In the case of taurine, the decomposition rate is negligible at pH ≥ 3.2. In the pH 3.2−2.5 range, decomposition is lower than nitrosation but not negligible, and at pH ≤ 2.5 decomposition is faster than nitrosation. With homotaurine, HNO2 decomposition is negligible at pH higher than 4.1. In the pH 4.1−2.8 range, nitrosation is faster but decomposition should be considered, and at pH ≤ 2.8 decomposition is the dominant reaction.

Ancillary