A phenol-chloroform ratio of 1:1 is advantageous for the phase separation when using MaXtract Low and High Density, since the MaXtract interphase has the greatest stability at this ratio.
Methods using a phenol-chloroform ratio of as much as 6:1 are also possible with MaXtract. However, MaXtract can partly precipitate onto the bottom of the tube in this case.
If the phenol-chloroform ratio is greater than 1:1, it is necessary to use MaXtract Low Density Tubes. Note that this MaXtract type is not compatible with applications in which the aqueous phase has a high density (e.g., isolation of plasmid DNA and RNA).