2.5. The Recovery Procedure
Water samples were collected according to the recom-
mended standard methods [28]. Water samples were
spiked with a definite concentration of Fe(III) soluation
and 1 ml of 10
–4
M of the Schiff base was added. After
adjusting the pH with HNO3and/or NaOH, the solution
was shaked well and transferred to the measurement cell
to ensure complete complexation. The concentration of
metal ion determined spectrophotometrically and obtained
the recovery percentage.