Potential of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry to monitor the Ag body burden in individual Daphnia magna specimens exposed to Ag nanoparticles

Abstract

This work evaluates the potential of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) for the direct determination of the Ag body burden in individual specimens of Daphnia magna (a small aquatic invertebrate of approx. 2 mm length typically used in ecotoxicological studies) exposed to different Ag species, and particularly to Ag nanoparticles (NPs). It is shown that this technique offers unique features for this type of application, permitting the direct analysis of these organisms in a very straightforward way (only approx. 2–3 min are required for the analysis of every individual) and constructing the calibration curve with aqueous standards. Moreover, appropriate selection of the detector pixels used for signal quantification makes it feasible to achieve a very broad linear range for any set of experimental conditions, contrary to what occurs for traditional line source-GFAAS. This feature is particularly important for this application, as every Daphnia magna specimen can be measured only once and its Ag content is not known in advance. In this case, the use of central and/or side pixels permits achieving a working range between 3 pg and 1 μg for the 328.068 nm Ag line, thus allowing analysis of all the samples of interest with the same experimental settings.