The solid phase extraction method optimised in our previous
study (Tokalıog˘lu & Livkebabcı, 2009) was used for the determination
of Cu(II) and Fe(III) in food samples. The pH of 25 mL sample
solutions was adjusted to 5 using acetic acid/acetate buffer solution
and 1 mL of 0.5% (w/v) BPHA was added. The column was preconditioned
with the solution of pH 5 and the sample solution was
passed through the column at a flow rate of 4 mL min1. The metal
complexes retained on the resin were eluted with 15 mL of
1 mol L1 HCl in acetone. The eluate was evaporated to near dryness
on a hot plate, and it was diluted to 5 mL with 1 mol L1
HCl solution. The concentration of the metal ions in the final solution
was determined by FAAS. The blank analyses were made in the
same way.