The detection of metal ions was performed using a Shimadzu
(Columbia, MD) 680 atomic absorption spectrometer equipped
with a hollow cathode lamp and a deuterium background corrector
at the respective wavelengths using an air-acetylene flame
according to the instrumental parameters recommended by the
manufacturer. A Metrohm 691 pH/Ion meter with a combined
glass–calomel electrode was used for the pH adjustment.
AModel 794 MetrohmBasic Titrino instrument equippedwith a combined
glass-calomel electrode in an air-protected, sealed, water-based,
thermostatic, jacketed cell maintained at 25.0±0.1 °C in a constanttemperature
bath (Fisher brand model FBH604, LAUDA, Germany)
equipped with a stirrer, aswell as a10.0-mL-capacityMetrohm piston burette,
was used for potentiometric titration. The pH meter was calibrated
to measure -log [H+] in a 50% (V/V) dioxane-water solvent.