Abstract
A fast and sensitive on-line procedure for the determination of zinc in water and biological samples was developed. Zinc was preconcentrated in a mini-column packed with polyurethane foam (PUF) chemically modified with zincon
via
-N=N- bonding. The optimal conditions for preconcentration were pH 8.5 and sample flow rate of 4.0 mL min
−1
. Quantitative desorption of Zn(II) was obtained by 0.1 mol L
−1
hydrochloric acid and subsequent spectrophotmetric determination using 4-(2-pyridylazo)-resorcinol at 498 nm. The obtained detection limit was found to be 3.0 ng mL
−1
, precision (RSD) was 4.8 and 6.7% at 20 and 110 ng mL
−1
, respectively, for 60 s preconcentration time and enrichment factor was 31. The linearity range was from 10 to 120 ng mL
−1
and maximum sample throughput was 20 h
−1
. Finally, the method was successfully applied to the determination of zinc in tap water, Nile River water and human urine samples with RSD in the range of 1.1–8.3%.