Combination of Directly Suspended Droplet Microextraction and Flame Atomic Absorption Spectrometry for Determination of Trace Amounts of Iron and Copper

Abstract

A miniaturized liquid-phase extraction procedure based on directly suspended droplet microextraction combined with flame atomic absorption spectrometry was developed for determination of trace amounts of iron and copper, without any need for the centrifugation step for phase separation. The method was based on the extraction of the iron and copper complexes with 2-mercaptopyridine-N-oxide onto a microdrop of methyl isobutyl ketone (MIBK) as extractant solvent. The factors influencing the extraction were optimized. Under optimum conditions, an enrichment factor of ~25 was obtained for both iron and copper from only 6.5 mL of aqueous phase. The analytical curves were linear between 40-800 μg L-1 and 25-1200 μg L-1 for iron and copper, respectively. The limits of detection were 3.76 μg L-1and 1.84 μg L-1 for iron and copper, respectively. The developed method has been successfully applied for the determination of iron and copper ions in environmental waters, fruits, vegetables and also certified reference materials, with high efficiency.