engleski

Coupled system of ion-chromatography and inductively coupled plasma atomic emission spectrometry(IC-ICP)regard to iron speciation in natural water

The determination of the concentrations of the indivual physicochemical forms of the element in a sample that constitute elements total concentrations has been termed as "speciation analysis". The need for speciation occur especially where species are known to have a different impact and behaviour (toxicity and mobility). New analytical techniques with higher sensitivity and selectivity have solved problems of determina-tion of species at very low concentration levels. The analytical procedures are based on separation steps (GC, LC) and detection of the compounds with element-specific de-tector (AAS, ICP, MS). The determination of the oxidation states of iron in natural water systems has generally been achieved by complexation with specific chelating agents followed by spectro-photometric measurments or by voltametry. Both of techniques suffer from the inter-ferences caused by presence of variety of Fe(III) oxides or different ligands in real samples. Significant improvement have been realized by coupled systems IC-ICP where the only problem is coming from preparation and preservation of samples. Iron species in this work were separated as anionic complexes with the PDCA (pyridine-2,6-dicarboxilic acid) using Dionex HPIC-CS5 column. Ion chromatograph was connected with ICP spectrometer directly. The analogue signal from PMT was detected through a digital voltameter with sampling frequency of 2 Hz. Samples were analysed after preconcentration on HPIC-CG5 column. Comparision between obtained results and total iron determination with ICP was made. Most prominent iron emission line of 259.925 nm was used for all measurments of iron species content in samples, for tests of organic phase influence, and for the determination of detection limits.

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