Selective Determination of Cr(VI) by FAAS After Solid Phase Extraction on Bis(3-aminopropyl)amine-Bonded Silica Gel

Abstract

In this study, a novel method was developed for the selective determination of Cr(VI) based on column solid phase extraction (SPE) using bis(3-aminopropyl) amine-bonded silica gel (BAPA-SG). To optimize the SPE procedure, the effects of various variables, including pH, sample volume, eluent type and volume, matrix ions and sample flow rate, were studied. The column SPE studies showed that BAPA-SG could selectively collect Cr(VI) ions at the pH of 2.0 from a sample volume up to 1000 mL in the presence of Cr(III). The recovery of the Cr(VI) ions was not affected by anions and cations widely found in environmental water samples. Adsorbed Cr(VI) on the column could be easily eluted using 5.0 mL of a 2.0M HCl solution. Cr(VI) adsorption dynamics onto BAPA-SG were also studied batch-wise by investigating the effects of contact time, initial Cr(VI) concentration, and temperature. Increasing the temperature showed adverse effects on the adsorption of Cr(VI). A Langmuir model best fit the experimental data. The maximum adsorption capacity was 75.5 mg g-1. The developed SPE procedure was successfully applied to the determination of Cr(VI) in spiked solutions by flame atomic absorption spectrometry. The pre-concentration factor of 200 permitted a detection limit of 0.11 ng/mL.

Taking a deeper look into the roles of amines in atomic absorption spectrometry

“…The same amine-based extraction system, BAPA-SG, also allows for the selective separation at pH 2.0 of Cr (VI) in the presence of Cr (III) and determination by FAAS with air-acetylene. 106 The method uses a column solid phase extraction (SPE) and 5.0 mL of a 2.0 M HCl solution as eluent, although high temperature adversely affects Cr (VI) adsorption. Another study included a column packed with 3-(2-aminoethyl amino)propyl-bonded silica gel to recover Au (III) , Pd (II) and Cu (II) ions.…”

Speciation and Determination of Inorganic Antimony by Solidified Floating Organic Drop Microextraction and ETV-ICP-MS

“…Several detection techniques for elemental speciation mainly include atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry (ICP-MS), and atomic fluorescence spectrometry (7)(8)(9)(10)(11)(12)(13)(14). However, an effective separation and preconcentration method for elemental speciation is requred before analysis by these techniques.…”

On-line Solid Phase Extraction of Nickel, Copper, and Cadmium Using a Newly Synthesized Polyamine Silica Gel-loaded Mini-column for Flame Atomic Absorption Spectrometric Determination

“…Solid phase extraction (SPE) has many advantages such as simplicity, reliability, high concentration factor, ease of automation, rapid phase separation, speed, environmental friendliness, and short analysis time compared with other preconcentration methods (22)(23)(24)(25)(26)(27). SPE can be carried out in the on-line and offline mode.…”