The standard applies to aqueous solutions with a specific conductivity less than 300 mS/m (determined in accordance with NEN 6412) from which particles larger than 0.45 pm have been removed. The detection limit depends on the device used; In general, beryllium contents can be determined from 0.05 pg/l. For beryllium contents higher than 30 pg/l, use of the flame technique is recommended, see [2
NEN 6435-1983 history
1983NEN 6435-1983 Water - Determination of beryllium content by atomic absorption spectrometry (graphite furnace technique)