A method for stabilizing nucleic acids

A method for stabilizing nucleic acids by forming an insoluble ionic complex between nucleic acid and a surface active agent in a biological sample, comprising a step of contacting the biological sample with a stabilizing composition comprising surface-active amine compounds of the formula (I): R wherein R R and x is an integer of 0 or 1; and wherein the pH of the composition is in the range of 1 to 5.