Only analytical reagent grade reagents were utilized in the resultant study. All sample extraction and sample preparations were carried out via the use of distilled de-ionized water (18 MX cm1). The pH of the reaction mixture was maintained
through the use of an ammonium chloride (NH4Cl) buffer.21.25 g of NH4Cl (Asia Pacific Speciality Chemicals Ltd., Auburn,NSW, Australia) and 1.0 g of disodium ethylenediaminetetraacetic acid dehydrate (EDTA) (Sigma–Aldrich, U.S.A) were dissolved and diluted to 1 L. The pH was adjusted to 8.5 using NaOH (10% w/v) solution. The color-developing reagent (Griess Reagent) used for the analyti calprocedure comprised of sulfanilamide (SA) and
N-(1-naphthyl)ethylenediamine dihydrochloride (NED). 10.0 g of SA(Ajax FineChem, NSW, Australia) and 0.25 g NED
were dissolved in 1L water in a volumetric flask. 100 mL of phosphoric acid (25% v/v) solution was subsequently added and diluted to mark and stored in a dark amber bottle