Dear all, I have to compare the english and german notations for analytical gases (esp. oxygen or helium). Surprisingly, I could not get this information from german companies. Could anybody of you give me the german grade of purity (5.6 or 4.5) which corresponds to the english cp-grade. Many thanks in advance Andreas -------------------------------------------- Andreas Lücke Forschungszentrum Jülich Institute for Chemistry und Dynamic of the Geosphere, ICG-4 Abt.: Isotopegeochemistry und Palaeoclimate D-52425 Jülich tel.: +49-(0)2461-61-4590 fax: +49-(0)2461-61-2484 e-mail: [log in to unmask] ----------------------------------------------------------