Prior to use, the glass carbon disk electrode was polished with
a 0.3–0.05 m alumina slurry on a felt pad, then thoroughly rinsed
with water, and sonicated in HNO3, ethanol, and distilled water.
After being cleaned, a bismuth film was potentiostatically electrodeposited
on a GCE by applying −1.0 V for 5 min in a 100 mg/L
Bi3+ and 1 mol/L HAc–NaAc aqueous solution. Then the three electrodes
were immersed into 20 mL of 0.15 mol/L HAc–NaAc solution
that contained aliquots of Se(IV), p-aminobenzene sulfonic acid and
cetyltrimethylammonium bromide (CETAB). The preconcentration
time was 120 s with stirring and another 10 s without stirring, then
cathodic stripping voltammetry (CSV) was performed in the differential
pulse mode with the following parameters: pulse amplitude,
50 mV and time pulse, 0.006 s; voltage step, 5 mV and voltage step
time, 0.1 s; sweep rate, 50 mV/s; before each measurement, the
electrode was cleaned at −1.3 V for 10 s.
The real sample analysis procedure was as follows: the 0.5 g