Chemical composition analysis of alkali borate and alkali germanate glasses

Borate and germanate anions in aqueous solution combine with two molecules of mannitol to form a borate mannitol complex or a germanate mannitol complex if sufficient mannitol is present. The formation constants of these two complexes are in close agreement which indicates a striking chemical similarity between these two complexes. Both complexes are moderately strong acids so that the compositions of alkali borate and alkali germanate glasses can be determined by the same potentiometric titration method.