Antimony determination in marine sediments by graphite furnace atomic absorption spectrometry with slurry sampling

A method for the determination of antimony in a slurry of marine sediment samples was developed. The temperatures of the graphite furnace program were optimized using a mixed chemical modifier consisting of palladium and magnesium nitrate and a wavelength of 217.6 nm. Under these conditions, the background levels were very high and the atomization profile showed a pronounced baseline rendering quantification impossible; this effect can be due to the presence of silicon in the sample. The experiments were repeated using the 206.8-nm antimony line at which no negative baseline was observed and the background levels decreased. Therefore, this absorbance line was selected for the determination of antimony in this work. The graphite furnace program was optimized using the mineralization and atomization temperatures of 1400 and 1700 °C, respectively. The concentration of the matrix modifier was also investigated and best results were obtained with 40-30 mg L -1 of palladium and magnesium nitrate, respectively. The analytical characteristics were 0.8 and 2.8 μg g -1 for the detection and quantification limits, respectively, with a characteristic mass of 18.8 pg and 95.6% of recovery percentage. The method was applied to the determination of antimony in different surface marine sediment samples obtained from Ria de Arousa (NW Spain).