Multi-wavelength spectrophotometric determination of Cr(VI) in water with ABTS. (March 2017)

• Record Type: Journal Article
• Authors: Fan, Wenjuan; Qiao, Junlian; Guan, Xiaohong
• Is Part Of: Chemosphere. Volume 171(2017)
• Page Start: 460
• Page End: 467
• Publication Date: 2017-03
• Subjects: Cr(VI) -- ABTS -- Oxidation -- Determination; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2016.11.153
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A new method for Cr(VI) (0.025–8.00 mg/L) determination based on the reaction of Cr(VI) and 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solutions was developed. The colorless ABTS reacted with Cr(VI) under strong acidic conditions ([H + ] = 3.0 or 6.0 M) producing a stable colored radical ABTS +, which could be measured spectrophotometrically at 415, 649 or 732 nm. The absorbance increase at these three wavelengths for ABTS + generation were all linear (less than 1.0% deviation) with respect to the amount of added Cr(VI) and the sensitivity were 1.099 × 10 5, 3.720 × 10 4, and 4.150 × 10 4 M −1 cm −1 of added Cr(VI) at 415, 649 or 732 nm, respectively. Cr(VI) of 0.025 mg/L below the discharge standard of drinking water could be detected with the method quantitatively and 0.002 mg/L Cr(VI) was determined qualitatively. The molar absorptivity of ABTS + generated was determined to be (3.69 ± 0.01) × 10 4 M −1 cm −1 at 415 nm and the reaction between Cr(VI) and ABTS had a stoichiometric factor of 1:3 in excess of ABTS. The absorbance of generated ABTS + was found to be stable in deionized water or wastewater and Cr(VI) spiked in wastewater could be determined accurately. The ABTS method also had a good anti-interference performance against Co(II) ions. Moreover, the ABTS method could be successfully used in the Cr(VI)-S(IV) system for Cr(VI) determination. Graphical abstract: The graphic abstract showed Cr(VI) determination based on the reaction between Cr(VI) and ABTS. Highlights: Cr(VI) of 0.025–8.00 mg/L could be determined with the ABTS method. The absorbance of ABTS + at 415, 649 or 732 nm can be used for Cr(VI) analysis. The ABTS method has excellent convenience, flexibility and sensitivity. The ABTS method has a good anti-interference performance.