This article compares the solid phase extraction (SPE) and coprecipitative preconcentration of cadmium and lead from dilute aqueous solutions
as a function of pH and weight of chelating agent. SPE enriches cadmium and lead over a wider pH range (6.0–8.0) and requires lower weight
of DBQ chelate embedded benzophenone. Among the quinoline-8-ol and its dihaloderivatives, DBQ embedded benzophenone allows quantitative
enrichment over a wide pH range (6.0–8.0) for both cadmium and lead unlike DCQ (∼6.5 for Cd and 6.5–7.0 for Pb), DBQ was preferred. The
calibration plots were rectilinear over the concentration range of 0.1–50 and 2.5–200 g l−1 of cadmium and lead with detection limits of 0.1 and
2.0g l−1, respectively, which are 400 times lower than the direct FAAS method. The precision of the developed procedure is good as it provides
relative standard deviation values of 2.20 and 2.45% during five replicate determinations of 2 and 25 g l−1 of cadmium and lead, respectively. The
accuracy of the developed procedure was tested by analyzing certified reference materials (CRM’s) of soil and marine sediment samples supplied
by IAEA, Italy and NRC, Canada, respectively. Furthermore, the developed procedure has been successfully used for the speciative determination
of cadmium and lead in soil samples collected from the vicinity of industries in India.
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