Abstract
Hydrogen peroxide was used as an oxidant in Flow Injection
Analysis (FIA). The formation of gaseous components during the
analysis was suppressed by maintaining a concentration lower than
0.15% of hydrogen peroxide in 0.1 M NaOH. By this method Cr(III)
was oxidised on-line to Cr(VI) which was detected
spectrophotometrically at 548 nm by complexation with
1,5-diphenylcarbazide (DPC). Linear responses was found for
concentrations less than 20 mg/L and the sensitivities obtained of
the pure species were 0.0225 ± 0.0015 L/mg for Cr(III) and 0.0420
± 0.0015 L/mg for Cr(VI). For the speciation of Cr(III) and Cr(VI)
the analysis of both species was performed by treating them as
mutual interference’s. Thus, the total amount of chromium species
was measured by FIA and the total amount of chromium was measured
by Graphite Atomic Absorption Spectrometry (G-AAS). The speciation
was then performed at concentrations above 6 mg/L which is
suitable for on-line monitoring of e.g. waste waters.
Original language | English |
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Journal | Analytica Chimica Acta |
Volume | 361 |
Pages (from-to) | 125-131 |
ISSN | 0003-2670 |
Publication status | Published - 1998 |