DIN 38405-4:1985-07

The standard describes two chemical methods for the determination of dissolved fluoride in potable water, surface water and waste water. The first method works direct with the fluoride-ion-selective-electrode and is mainly used for potable- and surface-waters withfluoride-concentrations from 0,2 up to 2000 mg/l. The second method works with a digestion by sodium hydroxide and a following separation of fluoride by steam destillation. Afterwards the fluoride is to determine in the destillate by the fluoride-ion-selective-electrode. The method is suitable for high loaded waste water with fluoride-concentration higher than 0,2 mg/l.