A soft material for chromium speciation in water samples using a chemiluminescence automatic system. (April 2018)

• Record Type: Journal Article
• Authors: Fernandez, Cintia J.; Domini, Claudia E.; Grünhut, Marcos; Lista, Adriana G.
• Is Part Of: Chemosphere. Volume 196(2018)
• Page Start: 361
• Page End: 367
• Publication Date: 2018-04
• Subjects: Automatic system -- Chromium speciation -- Ionic liquids -- Multiwalled carbon nanotubes -- Chemiluminescence detection; BmimCl 1-Butyl-3-methylimidazolium-chloride -- C channel -- CNT carbon nanotubes -- EA electronic actuator -- FBA Flow-batch analysis -- IL Ionic liquids -- MDC mixing detection chamber -- MFS multicommutated flow system -- MWCNT Multiwalled carbon nanotubes -- V solenoid valve -- PP peristaltic pump; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.12.178
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A soft material formed by multiwall carbon nanotubes and 1-butyl-3-methyl imidazolium chloride was used as sorbent material to perform the chromium speciation in natural waters. This soft material was not yet used for the speciation of metals as chromium. Thus, a multicommutated flow system containing a minicolumn packed with the soft material was designed. The procedure was based on the capacity of the sorbent to retain Cr(VI) as Cr2 O7 = and allow to pass Cr(III) through the column. Then, a fully automated flow-batch analysis system was developed to quantify both species using chemiluminescence detection. Thus, Cr(III) was determined as catalyst of the luminol and hydrogen peroxide reaction and Cr(VI) as oxidant of luminol reaction. This represents a new approach because the oxidation of luminol using Cr2 O7 = has not been reported in literature. The variables of the two systems were optimized. The limits of detection were 1.4 μg L −1 for Cr(VI) and 4.0 μg L −1 for Cr(III). The precision of the method was 3.8% and 7.0% for Cr(VI) and Cr(III), respectively. The present method was applied to real water samples with recoveries between 95% and 107%. Besides, these results were in accordance with those obtained using inductive coupled plasma-optical emission spectrometry technique. Graphical abstract: Image Highlights: A sorbent based on MWCNTs and ionic liquid was used for the speciation of chromium. The speciation and detection of chromium was performed by using an automatic system. Cr(III) and Cr(VI) were detected by chemiluminescence reactions. Cr(VI) was determined by the oxidation of luminol with the Cr2 O7 = desorbed.