Graphite furnace atomic absorption spectrometry
(GFAAS) is one of the most common techniques
used for trace analysis of heavy metals as
it is highly sensitivity, has low detection limits,
and requires low sample volumes12. Direct determination
of trace amounts of cadmium and lead
in complicate matrices as food samples by GFAAS
is usually difficult owing to interferences and insufficient
detection power13–15. These difficulties
however have been recently overcome by research
on digestion16–18, preconcentration, and separation
methods including solvent extraction, coprecipitation,
ion exchange, and solid phase extraction procedures19.
Solvent extraction of different metal ions
has been widely employed in chemistry and industry
for many years. However, classical extraction methods
are usually time consuming, labour-intensive
and require relatively large volumes of high purity
solvents. Additional concern is the disposal of
used solvent which can create severe environmental
problems. Much interest has been recently focused
on replacing conventional solvent extraction methods
in isolating environmental pollutants with solid
phase extraction (SPE) techniques which are capable
of selectively removing trace metal ions from
complex matrices with minimal usage of organic
solvent20. The application of SPE to metal ions is
generally based on chelating matrices with current
interest in designing macromolecular chelators with
high sorption capacity, selectivity, and suitability 21