Determination of Chromium(III), Chromium(VI), and Chromium(III) acetylacetonate in water by ion-exchange disk extraction/metal furnace atomic absorption spectrometry

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy Vol. 93; pp. 28 - 33
• Main Authors: Kamakura, Nao, Inui, Tetsuo, Kitano, Masaru, Nakamura, Toshihiro
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2014
• Subjects: Chromium(III); Chromium(III) acetylacetonate; Chromium(VI); Metal furnace atomic absorption spectrometry; Solid-phase extraction; Chromium(III); Chromium(III) acetylacetonate; Chromium(VI); Metal furnace atomic absorption spectrometry; Solid-phase extraction
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2014.01.003

A new method for the separate determination of Chromium(III) (Cr(III)), Chromium(VI) (Cr(VI)), and Cr(III) acetylacetonate (Cr(acac)3) in water was developed using a cation-exchange extraction disk (CED) and an anion-exchange extraction disk (AED) combined with metal furnace atomic absorption spectrometry (MFAAS). A 100-mL water sample was adjusted to pH5.6 and passed through the CED placed on the AED. Cr(acac)3 and Cr(III) were adsorbed on the CED, and Cr(VI) was adsorbed on the AED. The adsorbed Cr(acac)3 was eluted with 50mL of carbon tetrachloride, followed by the elution of Cr(III) with 50mL of 3molL−1 nitric acid. Cr(VI) was eluted with 50mL of 3molL−1 nitric acid. The chemical species of Cr eluted from the CED with carbon tetrachloride was identified as Cr(acac)3 using infrared spectroscopy. The eluate of Cr(acac)3 was diluted to 100mL with carbon tetrachloride, and those of Cr(III) and Cr(VI) were diluted to 100mL with deionized water. All of the solutions were subsequently analyzed by MFAAS. The calibration curve for the Cr(acac)3 aqueous solutions exhibited good linearity in the range of 0.1 to 1ng. The detection limit of Cr, which corresponded to three times the standard deviation (n=10) of the blank values, was 20pg. The recovery test for Cr(III), Cr(VI), and Cr(acac)3 exhibited desirable results (96.0%–107%) when 5μg of each species (50μgL−1) was added to 100mL water samples (i.e., tap water, rainwater, and bottled drinking water). In a humic acid solution, Cr(acac)3 was quantitatively recovered (103%), but Cr(III) and Cr(VI) exhibited poor recoveries (i.e., 84.8% and 78.4%, respectively). •A determination method of Cr(III), Cr(VI), and Cr(III) acetylacetonate in water was developed.•The combination of ion-exchange resin disks with metal furnace AAS was used.•No effect of humic acid on the recovery of Cr(III) acetylacetonate was observed.•The proposed method enabled the determination of three Cr species without subtraction.