The stripping signal for Sb(V) increased almost linearly up to 360 s. This indicates that no saturation of electrode surface was observed with in this time interval. This pattern undoubtedly allows operators to use correspondingly prolonged deposition time to achieve a higher sensitivity. Up to 240 s, the peak of antimony was sharp and the height increased linearly; further prolongation of the accumulation time gave higher but broader peaks. Hence, an accumulation time of 240 s was used in all subsequent measurements.