A method for isolating RNA from RNA containing samples wherein the RNA containing sample is treated with at least one DNase and/or another enzyme like proteases or collagenases for purification of RNA in presence of a complex of ribonucleosides and the oxovanadyl ion which is capable of inhibiting RNases present in the RNA containing samples and removing the complex of ribonucleosides and the oxovanadyl ion prior to down-stream processing of the RNA of the RNA containing sample by contacting the sample of the forgoing step with a chelating agent immobilized to a support, the chelating agent having sufficient affinity to the complex of ribonucleosides and the oxovanadyl ion so that it binds to the chemical entity and the RNA containing sample is freed from the inhibitor.