Magnetic Fraction of Fly Ash as a Low-Cost Magnetic Adsorbent for Selective Capture of Phosphoproteins

Abstract

In the present study, the magnetic fraction of fly ash was separated from the bulk material using a conventional magnet, yielding approximately 50% w/w. As the magnetic fraction of fly ash contains a high content of aluminum oxide, which is recognized as a phosphate adsorbent, and ferromagnetic iron oxides, it is potentially useful as a magnetic solid-phase extraction adsorbent of phosphoproteins. The results showed that the magnetic fraction of fly ash displayed a high enrichment factor of approximately 130-fold as a magnetic solid-phase extraction adsorbent. The phosphoprotein bound-magnetic fraction was efficiently isolated from the sample solution using a conventional magnet. The adsorbent was further applied to the isolation of phosphoproteins from biological samples, i.e., ovalbumin from egg white and caseins from milk. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the enrichment of phosphoproteins revealed that the eluted fraction contained more purified phosphoproteins comparing to the initial diluted samples. In addition, the adsorbent may be reused with acceptable adsorption capacity at least three times. The magnetic solid-phase extraction using the magnetic fraction of fly ash as an adsorbent is effective, simple and reusable. Therefore, the magnetic fraction of fly ash may be an alternative low-cost magnetic adsorbent for the sequestration of phosphoproteins from complex samples.