Use of tartaric acid-citric acid-sucrose as chemical modifier for the determination of lead in several matrices employing ET AAS

The present paper proposes the employ of a mixture containing sucrose-tartaric acid-citric acid as chemical modifier for the determination of lead using electrothermal atomization with atomic absorption spectrometry (ET AAS). The reagent concentrations in the modifier solution were established using a mixture design. Using the optimized conditions the pyrolysis and atomization temperatures established were 900 and 2000 °C, respectively. So, the method allows the determination of lead with limits of detection and quantification of 0.14 and 0.46 μg L− 1, characteristic mass of 18 pg and a precision expressed as relative standard deviation of 1.3%, 2.6% and 4.0% for lead solutions with concentrations of 10.0, 5.0 and 2.0 μg L− 1, respectively. The accuracy was confirmed by analysis of the following certified reference materials: NIST SRM 1515 (apple leaves), NIST SRM 1570a (trace elements in spinach leaves), NIST SRM 1643e (trace elements in water), CASS-4 (nearshore seawater) and BCR-713 effluent wastewater IRMM. The method proposed was applied for the determination of lead in surface water samples collected in the Paraguaçu River, Cachoeira City, Brazil in August 2015. Nine samples were analyzed and the lead content found varied from 0.64 to 8.25 μg L− 1, being always lower than the permissible maximum level stipulated by the Brazilian Ministry of Health, which is 10.0 μg L− 1.