Clay minerals are planar hydrous aluminium phyllosilicates with a high surface area-to-volume ratio. Previous studies have shown that the surface of clay minerals can adsorb DNA, and the amount adsorbed is usually measured by ultraviolet-visible light (UV-Vis) spectroscopy. In this study, a one-pot Fourier transform infrared (FTIR) setup is tested to allow for real-time liquid reaction monitoring. Once the required components are identified, continuous measurement of FTIR spectra can be performed allowing for real-time monitoring of the ongoing reaction without further manual operation. Compared with the existing adsorption quantification methods, the one-pot FTIR is thus simpler and more efficient for studying DNA adsorption to clay. For the interaction to proceed in such a setting, a clay sample must be made into a stable thin film in contact with liquid water during the adsorption of DNA. In this study, two types of clay minerals, Montmorillonite and Nontronite, were tested to explore the viability of the one-pot FTIR spectroscopy in monitoring the interaction between DNA and the clays.
The results indicated that when the target component in the liquid is sufficient (such as water and clay), one-pot FTIR can be conducted to record its changing concentration as a function of time, except for DNA in the dry-to-wet measurements. This may be due to interference from the DNA being added as a diluted liquid, for FTIR is a water-sensitive technique.