Combination of sonication and heating for metal extraction from inorganic fertilizers prior to microwave-induced plasma spectrometry determinations

This work reports a fast and efficient method for metal extraction in inorganic fertilizers by combining heating and sonication using an ultrasonic bath. Microwave-induced plasma optical emission spectrometry (MIP OES) was applied for the determination of Cd, Cu, Cr, Mn, Pb, and Zn in the extracts. Higher efficiency of metal extraction (similar to 100% for all metals except to Cd) was obtained for the treatment of 150 mg of fertilizer with 4 mL of 50% (v/v) HCl sonicated for 10 min and heating at 85 degrees C. Extractions applying only heating did not provide satisfactory results. The proposed procedure is simple and contributes to reduced production of waste in comparison to the official method. (C) 2015 Elsevier Ltd. All rights reserved.