Biomaterials for Bone Regeneration

248 Biomaterials for Bone Regeneration

The third alternative is the use of ion-selective electrodes (ISE). The prin-

ciple of the measurement here is the conversion of ion activity to an elec-

tric potential (Bobacka et al ., 2008). However, there are no ISEs developed

especially for the determination of magnesium, only for the combination

of divalent cations (Ca

2+

and Mg

2+

; so-called water-hardness electrode). As

Ca

2+

-selective electrodes are also available, it would be straightforward to

use both ISEs to take the same measurement, and then use a simple sub-

traction to obtain a result. Unfortunately, this approach does not work, as

both types of electrodes are prone to interference with both ions. Again, this

method is very reliable for ...