Question

Explain why atomic absorption spectroscopy and ion chromatographic (IC) technique are used as complementary techniques for water analysis.

Answer 1

two different analytical techniques: a spectroscopic method, atomic absorption, and a chromatographic one to determine the total heavy metal concentrations in water and sediment samples. The intention is to establish a correlation between these two techniques in the complex matrices that produce many interference problems . The ion chromatographic (IC) technique has generally been described in the literature for heavy elements analysis in a simple matrix such as water. Atomic absorption (AAS) is an important instrumental technique for the determination of trace heavy metal ions because of its low cost and short analysis time.   metal ions are present in their hydrated
forms. Hydrated metal ions are usually written without the water ligands included in the chemical formula. For example, chromic ion, Cr3 þ , is actually the hexaquo complex Cr(H2O)6
3 þ . Hydrated metal ions can also be complexe by weak ligands such as organic acids or
amino acids. These ligands are generally displaced by the complexing agents used in IC eluants. Therefore, the IC methods described here will determine the total of both the hydrated and weakly complexed metal ions. More powerful complexing agents will not be displaced during
chromatography. Since most complexing agents are anionic, the resulting metal complex will have a net negative charge. One example is the trivalent anionFe(CN)6 3- . Metals can also exist as oxyanions. Theseare actually metals with oxygen atoms as ligands. One example is the chromate ion, CrO4 2 - . The chromatography of these ions will be different from the hydrated
and weakly complexed metal ions, therefore, they must be determined using different IC methods. Metal oxyanions and other stable metal complexes are usually determined by anion exchange separation and suppressed conductivity
detection. And anion can be determined by atomic absorption spectroscopy