3.10. Application to distilled water and food samples
The proposed method was applied to the extraction and
determination of Pb2+, Cu2+, Zn2+ and Cd2+ in distilled water. As
shown in Table 3, a good agreement was obtained between the
added and measured (high recoveries and low RSD%) of spiked
samples indicates the capability of the method for the preconcentration
and the determination of these metals ions. On the other
hand, validation of the method was performed using a comparison
of the results obtained by the proposed method and determination
by flame atomic absorption spectrometry after concentration by
evaporation. As can be seen in Table 3, they are in satisfactory
agreement.
To assess the applicability of proposed method in real samples
an attempt was made to determine Pb2+, Cu2+, Zn2+ and Cd2+ ions
in various food samples including black tea, pepper, tomato, grape,
okra, spinach, mint and coriander by standard addition method.
The results obtained by the proposed method and inductively coupled
plasma atomic emission spectrometry (ICP-AES) after a
10-fold preconcentration (by evaporating the solution) are given
in Table 4. A good agreement between the two methods and low
RSD indicate the capability of the proposed procedure for the preconcentration
and the determination of Pb2+, Cu2+, Zn2+ and Cd2+ in
all of the food samples and confirm the accuracy of the proposed
method and its independency from matrix effects.