The determination
of Cu was conducted by using a GBC Model 903 flame and
graphite furnace AAS depending on the sample concentrations.
Standard addition method was employed to overcome
possible matrix interferences. The carbonate content was
estimated by back titrating with 0.5 M NaOH an excess of
0.5 M HCl added to 5.0 g of dry sand sample. The organic
matter content was estimated by determining the difference
between loss of ignition and carbonate content with the
former quantity obtained by heating the sand sample in
furnace at 900°C for 3 h
2000 rpm for 15 min and stored in polyethylene sample
bottle before analysis. The residue was washed with deionized
water before a new extraction stage.