Contamination problems from glass beaker inner surface in low level 210Po analysis

It was found that heating of diluted nitric or hydrochloric acids in many years stored glass beakers can result in mBq quantities of 210Po leached from beaker walls to the solution. In the case of freshly bought beakers acid leaching of 210Po was not observed. We suppose that acid leachable 210Po in old beakers is mainly due to implantation of radon progenies (from air) into superficial layers of glass beaker walls.