Finally, 4-nitrophenol adsorbed on
SWCNH-modified GCE was determined by linear sweep voltammetry
with a scan rate of 100mV/s. After each measurement, the
SWCNH-modified GCE under went successive cyclic voltammetric
sweeps between −0.3V and −1.0V at 100mV/s in pH 7.0 phosphate
buffer solution to refresh the electrode surface.