Spectroscopic study of maghemite nanoparticles surface-grafted with DMSA.
J Phys Chem A
; 115(6): 1003-8, 2011 Feb 17.
Article
em En
| MEDLINE
| ID: mdl-21261312
Nanosized maghemite (below 10 nm average diameter), surface-functionalized with meso-2,3-dimercaptosuccinic acid (DMSA), was investigated with respect to the content of DMSA molecules attached onto its surface and the onset of S-S bridges due to oxidation of neighboring S-H groups. To support our investigation, we introduced the use of photoacoustic spectroscopy to monitor thiol groups (S-H) conjugated with Raman spectroscopy to monitor the disulfide bridges (S-S). The normalized intensity (N(R)) of the Raman feature peaking at 500 cm(-1) was used to probe the S-S bridge whereas the normalized intensity (N(P)) of the photoacoustic band-S (0.42-0.65 µm) was used to probe the S-H moiety. The perfect linearity observed in the N(R) versus (1 - N(P)) plot strongly supports the oxidation process involving neighboring S-H groups as the DMSA surface grafting coefficient increases whereas the approach used in this report allows the evaluation of the [S-H]/[S-S] ratio. The observation of the reduction of the hydrodynamic diameter as the nominal DMSA-grafting increases supports the proposed model picture, in which the intraparticle (interparticle) S-S bridging takes place at higher (lower) DMSA-grafting values.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Compostos de Sulfidrila
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Compostos Férricos
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Succímero
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Nanopartículas
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Modelos Químicos
Idioma:
En
Revista:
J Phys Chem A
Assunto da revista:
QUIMICA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos