Water used for rinsing and dilution of reagents (MQ)was purified by reverse osmosis (Millipore) and deionisation (Milli-Q). An aqueous stock solution containing 0.01 M salicylaldoxime (SA) was prepared in 0.1 M HCl. Copper standard solutions were prepared by dilution of an atomic absorption spectrometry standard solution (BDH SpectrosoL grade) in 0.01 M HCl. A pH buffer containing 1 M boric acid (Aristar grade) and 0.35 M ammonia was UV-irradiated for 45-min to remove
organic contaminants.