Patent ID: 8076069

Claim:
A method for selective masking of at least one species of a nucleic acid in a sample, wherein said sample comprises at least one first species of a nucleic acid and at least one second species of nucleic acid different from the first species, the method comprising: A) providing said sample which contains at least two different species of nucleic acid, B) contacting the sample with a fluid and/or solid composition to produce a sample preparation, wherein said composition comprises at least one nitrogenous compound selected from the group consisting of spermidine, ammonium sulfate, ammonium hydrogenphosphate, glycine, 2,3-dimethylpyrazine, benzimidazole, imidazole, arginine, histidine, urea, and distamycine; whereby the producing of said sample preparation is carried out such that said sample comprising at least one first and at least one second species of nucleic acid is mixed with, and/or dissolved and/or suspended in said composition to form said sample preparation, and wherein the ratio of the concentration of said first species of nucleic acid to the concentration of said second species of nucleic acid in said sample is the same as the ratio of concentration of said first species of nucleic acid to the concentration of said second species of nucleic acid in said sample preparation, whereby the amount of the nitrogenous compound is chosen so that the second species of nucleic acid is masked in such a manner that the first species of nucleic acid can be more readily detectable in a detection method for nucleic acids, compared to the same detection method in which said nitrogenous compound is not present.