in order to activation.
The activated membranes were washed with distilled water and
stored in water at 4 C.
For bonding of methyl orange indicator to triacetylcellulose
membranes, after drying triacetylcellulose membranes were transferred
into a beaker containing 10 mL solution of methyl orange
with concentration of 105 M in 0.02 M sodium dihydrogen phosphate
(pH = 2). After 5 min the membranes were removed and
washed with water to remove any unbonded dye. The sensors were
stored in distilled water until analysis.