
263Nanocrystalline Diamond Biosensors
than just one, and thus the name impedance spectrum. The spectrum is analyzed by
tting a circuit model to the data, and values of each element of the circuit are used
to provide quantitative information about the properties of the surfaces, membranes,
exchange current, and diffusion processes. The simplest circuit that is used is RC circuit
in which the real part of the impedance represents resistance, and is given as Z
re
= R,
and imaginary part represent capacitance, Z
im
= 1/ωC and the magnitude of Z is written
as
ZZ ZR/C
re im
2
222
22
1=+ =+w
(Bard and Faulkner, 2nd edition). Thus, from the real
and imagi ...