Complexation of Hydrofloric Acid with Boric Acid

A complexation process for hydrofluoric acid (HF) with boric acid (H3BO3) is introduced below. Microwave digestions with HF are conducted to digest all metals from the matrices containing silicates and oxides. These digestions should be performed with two steps if it is necessary to complex the residual HF in the sample solution. The first step is the microwave digestion of a sample as dedicated Application Notes for the respective sample. The second step is the complexation with boric acid as described in this technical note. The advantages of using this complexation step is to eliminate formation of insoluble fluoride precipitates (e.g. Ca, Al and Mg) and volatilization of silicon as SiF4.