Application of portable spectrometer for ultra trace metal analysis after ionic liquid based microextraction

Abstract

In this work, a commercially available portable tungsten coil electrothermal atomic absorption spectrometer (W-coil ET-AAS) was applied and investigated. The portable AAS instrument was developed based on a W-coil atomizer and a charge coupled device detector, and has the characteristics of compactness and portability. In this research, ionic liquid based liquid phase microextraction (IL-LPME) was coupled with a portable AAS instrument to expand its application and improve its analytical performance. Ultra trace lead and copper were investigated as the target elements in the established coupling. The factors influencing both IL-LPME and the portable spectrometer were optimized. Under the optimal conditions, the limits of detection for lead and copper were 0.25 μg L⁻¹ and 0.10 μg L⁻¹, with sensitivity enhancement factors of 38 and 26, respectively. The relative standard deviation (RSD) for seven replicate measurements of 20 μg L⁻¹ of lead was 4.9%, and 10 μg L⁻¹ of copper was 3.4%. The recoveries for the spiked samples were in the acceptable range of 92.7–105%.