Speciation and preconcentration of chromium in real samples by magnetic polythiophene nanoparticle solid-phase extraction (SPE) coupled with microsampling injection – flame atomic absorption spectrometry (FAAS)

Chromium speciation in water using magnetic polyaniline nanoparticles coupled with microsampling injection-flame atomic absorption spectroscopy

“…Presumably, the PANI coated on the Fe 3 O 4 surface is partially stripped off by the acidic solution used as the eluent in the first adsorption-desorption cycle, resulting in a decline in the analytical performance of Fe 3 O 4 @PANI NPs. It could be concluded from previous studies that this is one of the most important disadvantages of direct polymer coating on the Fe 3 O 4 surface [ 22 , 26 , 44 ].…”

“…On the other hand, the experimental isotherm data are mostly evaluated using Langmuir and Freundlich isotherms to describe the interaction of an analyte with an adsorbent [ 44 , 49 , 50 , 52 ]. The characteristic Figures obtained from both isotherms applied to experimental data were given in Table 3 .…”

“…The Langmuir isotherm provides information on the adsorption capabilities of Fe 3 O 4 @PANI. The essential characteristic of a Langmuir isotherm can be expressed in terms of a dimensionless constant separation factor, R L , defined by the R L = 1 / (1 + K b C o ) equation, where C o is the initial concentration, and R L indicates the favorability of a sorption system (R L > 1 unfavorable; R L = 1 linear; 0 < R L < 1 favorable, and R L = 0 irreversible) [ 44 , 52 – 55 ]. R L values corresponding to initial concentrations Cr(III) in the range of 1 to 30 mg L −1 vary from 0.695 to 0.071, indicating favorable chromium adsorption on Fe 3 O 4 @PANI.…”

Optimized Preconcentration Method Using Ionic Liquid Ferrofluid for Ultra-Trace Determination of Cr(VI) in Drinking Water by Inductively Coupled Plasma Mass Spectrometry

“…The adsorption of Cr(VI) may be due to the electrostatic attraction between the anionic Cr(VI) (CrO4 2-, HCrO4 2-, and Cr2O7 2-) and protonated amine. [59][60][61] It decreased at pH > 6 (not shown), likely as a result of competition from hydroxide ions. 55 This is in good agreement with previous studies on different adsorbents.…”

Polymeric Materials in Speciation Analysis Based on Solid-Phase Extraction

“…An analytical procedure developed was used for As speciation in natural and environmental water samples. Well-known sorbent magnetite coated with polythiophene was tested for Cr speciation in a microsample injection system FAAS [ 77 ]. It was found that Cr(III) is selectively retained in the presence of Cr(VI) and an analytical approach was developed for the determination of Cr(III), total Cr (after reduction of Cr(VI) and Cr(VI) by subtraction.…”