The quantities of the various chemicals in recipes for CTAB buffer differ by lab. However, all include the ingredients 1 M Tris HCl pH 8.0, 0.5 M EDTA, 5 M NaCl and H2O (sometimes double distilled). For the CTAB component, some labs use cetyltrimethylammonium bromide, and some use hexadecyltrimethylammonium bromide.
Preparing the plant tissue can vary depending on the material. Cell walls and membranes must be broken down to access the nuclear material without any degradation. Usually, grinding the plant material with liquid nitrogen allows access to DNA while keeping harmful cellular enzymes and chemicals inactive.
The ground tissue is suspended in the CTAB buffer and put in a circulating water bath. Next, it is mixed with chloroform and centrifuged to separate soluble proteins and other material. DNA is then precipitated from the aqueous phase and thoroughly washed to remove contaminating salts. The purified DNA is then suspended and stored in TE buffer or sterile distilled water.