Adenine Adsorbed onto Montmorillonite Exposed to Ionizing Radiation: Essays on Prebiotic Chemistry
Por:
Baú J.P.T., Villafañe-Barajas S.A., Da Costa A.C.S., Negron-Mendoza, Alicia, Colin-Garcia, Maria, Zaia D.A.M.
Publicada:
1 ene 2020
Ahead of Print:
1 sep 2019
Resumen:
Most adsorption and radiolysis experiments related to prebiotic
chemistry studies are performed in distilled water or sodium chloride
solutions. However, distilled water and sodium chloride solutions do not
represent the composition of the primitive seas of Earth. In this work,
an artificial seawater with ion abundances Mg2+ > Ca2+ >> Na+
approximate to K+ and SO42- >> Cl- was used, one that is different from
the average composition of seawater today. This artificial seawater is
named seawater 4.0 Ga, since it better represents the composition of the
major constituents of seawater of primitive Earth. The radiolysis of
adenine adsorbed onto montmorillonite was studied. The most important
result is that adenine is adsorbed onto montmorillonite, when it is
dissolved in artificial seawater 4.0 Ga, and the clay protects adenine
against gamma radiation decomposition. However, desorption of adenine
from montmorillonite was possible only with 0.10 mol L-1 of KOH. This
result indicates that adenine was strongly bonded to montmorillonite.
Fourier transform infrared spectroscopy showed that NH2 group and
electrostatic interactions, between negatively charged montmorillonite
and positively charged adenine, are responsible for adsorption of
adenine onto montmorillonite. In addition, X-ray diffractograms showed
that adenine enters in the interlayer space of montmorillonite.
Filiaciones:
Laboratório de Química Prebiótica, Departamento de Química-CCE, Universidade Estadual de Londrina, Londrina, Brazil
Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, Mexico
Departamento de Agronomia-CCA, Universidade Estadual de Maringá, Maringá, Brazil
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, Mexico
Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, 04510 Cd. Mx., Mexico
Univ Estadual Londrina, Dept Quim CCE, Lab Quim Prebiot, BR-86051990 Londrina, PR, Brazil
Univ Nacl Autonoma Mexico, Posgrad Ciencias Tierra, Ciudad Univ, Cd Mx, Mexico
Univ Estadual Maringa, Dept Agron CCA, Maringa, Parana, Brazil
Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Ciudad Univ, Cd Mx, Mexico
Univ Nacl Autonoma Mexico, Inst Geol, Ciudad Univ, Cd Mx 04510, Mexico
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