ISO 13162 pdf download Water quality — Determination of carbon 14 activity — Liquid scintillation counting method Glass vials with low level of 40K, which exhibit a lower background than “normal” glass vials. Polytetrafluoroethylene vials (PTFE)or PE vials with a layer of PTFEon the inside wall, which are stronglyrecommended for the determination of very low 14C concentrations. Diffusion of organic...