Hybridization is carried out in conventional aqueous solvents at a temperature well below the predicted melting temperature. Nonspecific hybrids are then removed by washing at high stringency in buffers containing quaternary salts. Tetramethylammonium chloride (TMACl) is used with probes that are 14-50 nucleotides in length, whereas tetraethylammonium chloride (TEACl) is used with longer oligonucleotides.
