The effects of p-anisidine concentration on the peak heights for
vanadium and iron are shown in Fig. 2(a) and (b), respectively. For
both analytes, uncatalyzed (○) and catalyzed (□) reactions were
promoted at the higherp-anisidine concentration. Taking into
accounts the net absorbance values (▲) and lower blank peak
heights,p-anisidine concentrations of 0.06 and 0.04 mol L
–1
were
chosen for vanadium and iron determination, respectively.