They were also studied for their applicability in the production and purification of biodiesel, and their ability to extract metals for analysis. Incorporating microwave heating with deep eutectic solvent can efficiently increase the solubility power of DES and reduce the time required for complete dissolution of biological samples at atmospheric pressure. It is noteworthy that proton-conducting DES (e.g. the mixture of imidazolium methanesulfonate and 1H-1,2,4-triazole in a 1:3 mole ratio or the mixture of 1,2,4-triazolium methanesulfonate and 1H-1,2,4-triazole in a 1:3 mole ratio, wherein the Brønsted base may act as the hydrogen bond donor) have also found applications as proton conductors for fuel cells