Dn. Reinhoudt et al., DEVELOPMENT OF DURABLE K-SELECTIVE CHEMICALLY-MODIFIED FIELD-EFFECT TRANSISTORS WITH FUNCTIONALIZED POLYSILOXANE MEMBRANES(), Analytical chemistry, 66(21), 1994, pp. 3618-3623
Durable K+-selective chemically modified field effect transistors (CHE
MFETs) with functionalized polysiloxane membranes have been developed.
Polysiloxane membranes of different polarity, i.e., with different am
ounts of (cyanopropyl) siloxane groups, incorporating a free or covale
ntly bound hemispherand as the ionophore and free or covalently bound
tetraphenylborate anions as ionic sites, were investigated for their p
erformance as sensing membranes. The CHEMFETs based on polysiloxane wi
th both ionophore and anionic site covalently attached to the membrane
matrix showed K+ responses with an almost Nerstian slope in the range
of concentration 10(-4)-10(-1) M in the presence of 0.1 M Na+ (log k(
K,Na)(pot) = -3.2. Durability tests showed that these sensors respond
satisfactorily in the desired range of potassium concentrations even a
fter 10 months of continuous exposure to washing in a stream of tap wa
ter.