| Author/Editor | Milačič, R; Štupar, J; Kožuh, N; Korošin, J | |
| Title | Critical evaluation of three analytical techniques for the determination of chromium(VI) in soil extracts | |
| Type | članek | |
| Source | Analyst | |
| Vol. and No. | Letnik 117 | |
| Publication year | 1992 | |
| Volume | str. 125-30 | |
| Language | eng | |
| Abstract | Three different analytical techniques Š1,5-diphenylcarbazide spectrophotometry, chelating ion- exchange chromatography (Chelex-100), and ion-pairing reversed phase high-preformance liquid chromatography (RP-HPLC) combined with electrothermal atomic absorption spectrometry (ETAAS)Ć were critically evaluated for the determination of CR(VI) in the soil extracts. Spectrophotometry was not applicable to the analysis of the most soil extract samples owing to its high limit of detection (LOD = 30 ng cm-3), and the possibility of the instantaneous reduction of Cr(VI) under the acidic conditions employed. A Chelex 100 column, although adequately sensitive (LOD = 1.5 ng cm-3), is inclined to give higher results as inert and moderately labile Cr(III) complexes partially passed through the resin together with Cr(VI). In addition, very small particles (less than 0.45 micro meter) carrying chromium can produce severe positive systematic errors. In order to avoid this, filtration employing a 0.1 micro m filter is recommended. Ion-pairing RP-HPLC was found to be the most sensitive technique (LOD = 0.3 ng cm-3). It might also give high cromate results if negatively charged Cr(III) complexes form ion pairs with tetrabutylammonium phosphate and their elution partially coincided with that of Cr(VI). Fulvate ligands showed this type of interference. Reversed-phase HPLC is not suitable for analysis of extracts obtained from soils with freshly added tannery waste owing to the effects of the undestroyed tannery waste matrix. This study showed that each method investigated was vulnerable to some type of interference. | |
| Descriptors | CHROMIUM SOIL POLLUTANTS SPECTROPHOTOMETRY, ATOMIC ABSORPTION CHROMATOGRAPHY, ION EXCHANGE CHROMATOGRAPHY, HIGH PRESSURE LIQUID |