Hydrophobic magnetic deep eutectic solvent: Synthesis, properties, and application in DNA separation

•A series of hydrophobic magnetic deep eutectic solvents were prepared.•A hydrophobic magnetic deep eutectic solvent-vortex extraction method was developed for selective extraction of DNA.•The extraction method parameters were systematically optimized.•DNA in complex samples and E. coli cell lysate can be well extracted by the extraction method.•The extraction mechanisms were investigated by FT-IR and DFT calculation.