Microwave-assisted single-step extraction method for determination of heavy metals in saline soil and compare with conventional sequential extraction method

The present research assesses the chemical fractionation of cadmium (Cd), chromium (Cr), and lead (Pb) detected in saline soil samples of Hyderabad Pakistan. Based on the reagents used in the BCR three-step conventional sequential extraction (CSE) for partitioning Cd, Cr, and Pb in saline soil samples, a Microwave induced single-step extraction (MSE) method was developed. The validity of the method was confirmed using certified reference material (CRM) BCR-483 and the standard method of addition (recoveries 96–102%). The data provided by the BCR- CSE method for Cd, Cr and Pb partition were compatible with MSE using the same operating conditions applied and checked in BCR fraction by the Certified Reference Material (CRM) BCR-483. Using compromised sonication and microwave conditions steps 1–3 of the sequential extraction (excluding hydrogen peroxide digestion in step 3) could be accomplished with ultrasonic bath between 15 and 30 min, whereas 60–120 s needed for MSE. The total concentrations of Cd, Cr, and Pb extractable metals produced by three separate extractions ranged 1.02–3.30, 5.02–9.95 and 3.97–8.01 μgg−1, respectively. The accuracy of the proposed BCR single extraction methods (expressed as RSD %) for all metals was found within the range of (4.99–8.61%).