The standard applies to aqueous solutions with a specific conductivity of less than 300 mS/m (determined in accordance with NEN 6412) from which particles larger than 0.45 µm have been removed. The detection limit depends on the device used; In general, lead levels can be determined from 1 pg/l. For lead levels higher than 500 ug/l, the flame technology recommendation is recommended; see NEN 6453.
NEN 6429-1983 history
1983NEN 6429-1983 Water - Determination of lead content by atomic absorption spectrometry (graphite furnace technique)