Atomic absorption spectrometry 12 Electrothermal atomic absorption spectrometry 12 Absorption spectroscopy 10 Extraction 10 Flow injection 8 Silica 8 Trace analysis 8 Chlorine compounds 6 Mesoporous materials 6 Phase separation 6 Solid-phase extraction 6 Adsorption 4 Adsorption capacities 4 Atoms 4 Cadmium 4 Chromium compounds 4 Concentration (process) 4 Cr(III) 4 Cr(VI) 4 Hybrid materials 4 Hybrid mesoporous silica 4 Mesoporous silica MCM-41 4 On-line preconcentration 4 Potable water 4 Resins 4 article 4 atomic absorption spectrometry 4 autoanalysis 4 flow injection analysis 4 3-aminopropyltriethoxysilane 2