Aluminium as chemical modifier for the determination of lead in sugar cane spirits using electrothermal atomic absorption spectrometry

Abstract

Aluminium was used as a chemical modifier for the determination of lead in sugar cane spirit samples by electrothermal atomic absorption spectrometry (ET-AAS). Pyrolysis temperature, pyrolysis time and atomisation temperature were 800 °C, 20 s and 1800 °C, respectively. The aluminium mass was 3 µg. Lead was quantified with limits of detection and quantification of 0.14 and 0.47 µg L⁻¹, respectively, and a characteristic mass of 24 pg. Analyte addition experiments demonstrated that external calibration can be performed with aqueous standards. The precision, expressed as relative standard deviation (RSD%), was 3.11% for a sample with a lead concentration of 3.00 µg L⁻¹. There is currently no certified reference material for sugar cane spirits, so a standard reference material of orchard leaves was used to confirm accuracy. The proposed method was used to determine the lead content of five sugar cane spirit samples from Salvador City, Brazil. Their lead contents varied from 3.00 to 19.61 µg L⁻¹. The samples were also analysed by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion in a closed system. No statistical difference was observed between the results obtained by both methods.