Feulgen Hydrolysis: Effect of Acid and Temperature

Two methods of Feulgen hydrolysis (5.0 N HCl at room temperature and 1.0. N HCl at 60°C) were examined by serial microspectrophotometric measurements of the relative DNA content of normal human lymphocytes subjected to each hydrolysis. The DNA contents at optimum hydrolysis were equal by both methods. Hydrolysis in 5.0 N HCl at room temperature resulted in an interval of 120 min of stable peak values. Successive hydrolyses to the optimum time, as defined for each methtod in the initial experiment, indicated that hydrolysis 5.0. N HCl at room temperature provided a more reliable technique. The results also suggested that depurination is dependent primarily on acid rather than heat, while further degradation is dependent primarily on heat rather than acid.