A microfluidic device-based method for purifying nucleic acid from a lysed liquid sample solution, comprising: providing a suitable microfluidic device comprising a first purification matrix and a second purification matrix; performing a first purification step using the first purification matrix, the first purification step comprising the steps of: adding an organic solvent to the lysed solution; adding silica coated magnetic beads as the first purification matrix to the lysed solution; binding the nucleic acid to the silica coated magnetic beads; separating the nucleic acid-bound silica coated magnetic beads from the solution; washing the nucleic acid-bound silica coated magnetic beads with a wash solution; separating the washed silica coated magnetic beads from the wash solution; eluting the nucleic acid from the washed silica coated magnetic beads; performing a second purification step using the second purification matrix, the second purification step comprising the steps of: reestablishing an appropriate molecular charge on the eluted nucleic acid; re-capturing the nucleic acid from the solution on a silica column or silica filter; washing the re-captured nucleic acid with a wash solution; and eluting the re-captured nucleic acid to obtain a purified nucleic acid. providing a suitable microfluidic device comprising a first purification matrix and a second purification matrix; performing a first purification step using the first purification matrix, the first purification step comprising the steps of: adding an organic solvent to the lysed solution; adding silica coated magnetic beads as the first purification matrix to the lysed solution; binding the nucleic acid to the silica coated magnetic beads; separating the nucleic acid-bound silica coated magnetic beads from the solution; washing the nucleic acid-bound silica coated magnetic beads with a wash solution; separating the washed silica coated magnetic beads from the wash solution; eluting the nucleic acid from the washed silica coated magnetic beads; adding an organic solvent to the lysed solution; adding silica coated magnetic beads as the first purification matrix to the lysed solution; binding the nucleic acid to the silica coated magnetic beads; separating the nucleic acid-bound silica coated magnetic beads from the solution; washing the nucleic acid-bound silica coated magnetic beads with a wash solution; separating the washed silica coated magnetic beads from the wash solution; eluting the nucleic acid from the washed silica coated magnetic beads; performing a second purification step using the second purification matrix, the second purification step comprising the steps of: reestablishing an appropriate molecular charge on the eluted nucleic acid; re-capturing the nucleic acid from the solution on a silica column or silica filter; washing the re-captured nucleic acid with a wash solution; and eluting the re-captured nucleic acid to obtain a purified nucleic acid. reestablishing an appropriate molecular charge on the eluted nucleic acid; re-capturing the nucleic acid from the solution on a silica column or silica filter; washing the re-captured nucleic acid with a wash solution; and eluting the re-captured nucleic acid to obtain a purified nucleic acid.