
54-16 Chemical Variables
measurements simultaneously can allow contact resistance and conductivity changes in the main poly-
mer
to be in
dividually
ex
tracted
fr
om
th
e
se
nsor
sig
nal
. Bu
lk
me
asurements
(c
aptured
by tw
o-point
an
d
fo
ur-point
sig
nals)
an
d
co
ntact
re
sistance
(c
aptured
by on
ly
tw
o-point
me
asurements)
ca
n
ch
ange
di
erently
wi
th
an
alyte
co
ncentration
du
e
to de
lays
in th
e
di
usion
of an
alyte
th
rough
th
e
co
nducting
po
lymer
. u
s,
co
mbining
tw
o-
an
d
fo
ur-point
me
asurements
pr
ovides
in
formation
ab
out
an
alyte
co
n-
centration
bo
th
th
rough
bu
lk
re
sistance
an
d
th
e
ra
tio
of bu
lk
to co
ntact
re
sistance
. i
s
im
proves
bo
th
de
tection
li
mit
an
d
se
nsit ...