Fabric fiber sorbent extraction for on-line toxic metal determination by atomic absorption spectrometry: Determination of lead and cadmium in energy and soft drinks

A novel simple and sensitive on-line flow injection (FI) fabric fiber sorbent extraction (FFSE) system adapted to flame atomic absorption spectrometry (FAAS) for automatic trace metal determination has been established. The FFSE platform is based on polyester fabric fibers coated with sol-gel poly-dimethylsiloxane (PDMS) packed into a microcolumn as sorbent packing material. The potentials of this new scheme were assessed for direct Pb(II) and Cd(II) determination in energy and soft drink samples. The on-line retention of target analytes on sol-gel coated fibers was carried out with sodium diethyl dithiocarbamate (DDTC), while elution was performed with methyl isobutyl ketone (MIBK). The effect of the main chemical and flow parameters on the sensitivity of the method was thoroughly studied. For a loading time of 90 s with a sampling frequency of 30 h− 1, enhancement factors of 167 and 40 and detection limits (3σ) of 1.6 and 0.3 μg L− 1 were obtained for Pb(II) and Cd(II) determination, respectively. The trueness of the developed method was estimated by analyzing a certified reference material and spiked tap water.