A new coated–wire membrane selective electrode as a potentiometric sensor was
developed for the determination of isoproterenol. Naphthylethylenediamine dihydrochloride–
tetraphenyl   boranuide   ion–exchangers   was   used   as   an   electroactive   material   on   the
membrane.  The  sensor  displays  a  linear  response  with  a  slope  of  56.9  mV  decade –1   for
isoproterenol in the concentration range of 1.0×10 –2 –5.0×10 –6  mol L –1 , with detection limit of
3.3×10 –6  mol L –1 . The potentiometric response is independent of the pH of the solution in the
pH range of 3.0 – 6.8. Selectivity coefficient data for some common inorganic cations, sugars
and  components  of  the  mixed  drugs  were  investigated  and  showed  negligible  interference.
The  response  time  of  <5  s  was  displayed.  The  sensor can be  used  for more  than  2  months
without  any  considerable  divergence  in  the  potential.  For  the  practical  purposes,  the
efficiency of the method in the extraction and determination of isoproterenol for biological
fluids  such   as   urine   and   blood   serum   samples   was   evaluated   without   any   special
pretreatment.