A method has been developed for on-line liquid chromatographic separation of Cr(III) on a reverse phase C18 column in the presence of KH phthalate. KH phthalate, newly introduced into the chromatographic technique by us, is so much selective for Cr(III) in contrast to many complex-forming agents mentioned in the literature that in its presence practically no ion is sorbed on the C18 column except Cr(III). This is why practically no interference caused by the matrix was observed during the detection of Cr(III). Cr(III) sorbed on the column was eluted into the flame of an atomic absorption spectrometer using a mixture of methanol and water (80-20 %v/v). With 100 μl of sample solution, the detection limits (3σ) were found to be 0.024 ng/l and 0.075 ng/l for the separation of Cr(III) and Cr(VI) with FAAS detection and the time needed for separation was less than 60 s. In the case of the preconcentration of Cr(III) from 5 ml sample solution the detection limit (3σ) was 0.73 ng/ml, the accuracy of the measurement was 3.8 RSD% for the preconcentration of 20 ng/ml Cr(III). The sensitivity of the method permitted determination of Cr(III) and Cr(VI) in surface waters and various samples of natural origin below ng/ml concentrations. After reduction of Cr(VI) to Cr(III) with ascorbic acid and its preconcentration we were able to determine the total chromium content of various samples.
|Translated title of the contribution||On-line chromatographic separation of Cr(III)/Cr(VI) and preconcentration of Cr(III) using KH phthalate and their determination in various samples by flame atomic absorption spectrometry|
|Number of pages||10|
|Journal||Magyar Kemiai Folyoirat, Kemiai Kozlemenyek|
|Publication status||Published - Jul 1 1997|
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