Influence of some amino acids and vitamin C on the anodic dissolution of tin in sodium chloride solution

✍ Scribed by Mohamed Samir S Morad; Abo Alhagag A Hermas

• Publisher: Wiley (John Wiley & Sons)
• Year: 2001
• Tongue: English
• Weight: 432 KB
• Volume: 76
• Category: Article
• ISSN: 0268-2575
• DOI: 10.1002/jctb.397

✦ Synopsis

Abstract

The safety of canned foodstuffs should be evaluated not only by recognition of functional foods but also by the presence of toxicants in the human diet. In this study, the anodic dissolution of tin in 3.5% NaCl solution with and without 25–100 mM glycine, serine, methionine, vitamin C and some of their binary mixtures was studied by means of potentiodynamic and impedance techniques. The corroded tin surface was examined by SEM. The results indicated that the passive behaviour of tin is greatly improved by the presence of 50–100 mM glycine and methionine while such improvement is achieved only at 100 mM serine. Both cysteine and vitamin C showed aggressive action. The influence of the glycine/methionine mixture was found to be similar to that of the individual components, whereas the presence of cysteine in the cysteine/methionine mixture annuled the inhibiting action of methionine. The impedance results revealed that the dissolution reaction of tin in NaCl solution with and without glycine, serine and methionine is controlled by the charge transfer process while in the presence of cysteine and vitamin C, the mixed charge transfer and diffusion control is dominant. A rough, bare tin surface was observed in the presence of cysteine and vitamin C while a clean surface covered by corrosion products, in some zones, was observed in NaCl solution containing methionine.

© 2001 Society of Chemical Industry