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Adsorption Behavior of Amino Acids on a Stainless Steel Surface

2000; Elsevier BV; Volume: 229; Issue: 1 Linguagem: Inglês

10.1006/jcis.2000.7016

1095-7103

Koreyoshi Imamura, Tomoya MIMURA, Makoto Okamoto, Takaharu Sakiyama, Kazuhiro Nakanishi,

Polymer Surface Interaction Studies

The adsorption behavior of various amino acids on a stainless steel surface was investigated at 30°C and over a pH range of 3–10. Acidic and basic amino acids except histidine adsorbed remarkably at pH 3–4 and 7–10, respectively, and showed Langmuir-type adsorption isotherms. The effects of pH and ionic strength on the adsorption isotherms were investigated to analyze the interactions between amino acids and adsorption sites on the stainless steel. Hydrophobic amino acids and glycine showed only small adsorbed amounts at all pHs tested. For the acidic and basic amino acids, reversibility of the absorption and the influence of the ionic strength on the adsorption behavior were examined. The adsorption isotherms of the derivatives of aspartic acid were also measured in order to examine the contribution of the carboxylic groups of acidic amino acids to the adsorption. Furthermore, a Fourier-transform infrared spectroscopic analysis and semiempirical molecular orbital calculation were carried out to analyze the ionization states and the configuration of the amino acids adsorbed on a stainless steel surface. These investigations suggest that the acidic and basic amino acids adsorb through two electrostatic interactions of two ionized groups in the amino acid with a stainless steel surface.