Isolation of Nucleic Acids Using Fly Ash as a Low-Cost Adsorbent

Fly ash, a by-product generated from coal combustion, contains a high content of metal oxides which are recognized as efficient adsorptive materials for phosphate-containing molecules. This indicates the potential application of fly ash as a solid-phase extraction adsorbent to nucleic acids, the phosphate-containing biopolymers. However, little effort has been made to study and exploit fly ash properties for extracting nucleic acids. In this study, long double-stranded deoxyribonucleic acid (DNA) was used for examining the DNA adsorptivity of fly ash. On incubation with DNA, it required only two minutes for fly ash to adsorb DNA on the surface. This time was significantly shorter than other metal-oxide adsorbents such as Fe₃O₄@SiO₂ nanoparticles. In terms of desorption, DNA was rapidly eluted from the fly ash surface using phosphate buffer within a very short time of 5 minutes comparable to other metal oxide particles. Moreover, fly ash may be reused three times without significant loss of its adsorption capacity. Fly ash has been demonstrated to be a promising adsorbent in the DNA isolation process due to its low cost, reusability, and short-time extraction.