The derivatization reaction was carried out in alkaline media. Therefore,
the pH studies were performed in the range of pH 7.0-11.0
with concentrations of AP and K3Fe(CN)6 in the range of
0.005-0.05% (w/v) and 0.015-0.15% (w/v), respectively. It
was found that the highest change in absorbance was obtained
at pH 9.5, when concentrations of AP and K3Fe(CN)6 solutions
were 0.025% (w/v) and 0.075% (w/v). Larger amounts of AP
could disturb the detection of corn samples.