A novel method for fast enrichment and monitoring of hexavalent and trivalent chromium at the ppt level with modified silica MCM-41 and its determination by inductively coupled plasma optical emission spectrometry

Abstract

Recebido em 12/1/05; aceito em 25/8/05; publicado na web em 16/2/06 Chromium(III) at the ng L -1 level was extracted using partially silylated MCM-41 modified by a tetraazamacrocyclic compound (TAMC) and determined by inductively coupled plasma optical emision spectrometry (ICP OES). The extraction time and efficiency, pH and flow rate, type and minimum amount of stripping acid, and break-through volume were investigated. The method's enrichment factor and detection limit are 300 and 45.5 pg mL -1 , respectively. The maximum capacity of the 10 mg of modified silylated MCM-41 was found to be 400.5±4.7 µg for Cr(III). The method was applied to the determination of Cr(III) and Cr(VI) in the wastewater of the chromium electroplating industry and in environmental and biological samples (black tea, hot and black pepper).

Adsorption kinetic study: Effect of adsorbent pore size distribution on the rate of Cr (VI) uptake

“…Cr (VI) is an industrially important form of this element [2], however it is toxic and carcinogenic to humans and animals. Furthermore, Cr (VI) should not be digested due to its high mobility and bioavailability compared to the sparingly soluble trivalent Cr species [3]. Due to the different toxicities of Cr (VI) and Cr (III) analytical measurements should involve speciation rather than total Cr concentration to best evaluate the potential physiology and toxicological effects of exposure [4,5].…”

Highly porous silica‐polyaniline nanocomposite as a novel solid‐phase microextraction fiber coating

“…Mesoporous silica SBA-15, which possesses a large surface area and a tunable pore-size, has been used as a sorbent for the preconcentration of metals [22][23][24] and solidphase microextraction [25]. In order to increase the selectivity and improve the sorption properties of SBA-15 as a coating material for SPME fibers, we used aniline to fabricate SBA-15/polyaniline nanocomposites via chemical polymerization.…”

Study on solid phase extraction and graphite furnace atomic absorption spectrometry for the determination of nickel, silver, cobalt, copper, cadmium and lead with MCI GEL CHP 20Y as sorbent

“…The analytical performance of the method is comparable with other separationpreconcentration methods. The limits of detection of analyte ions are superior to those of some preconcentration/separation techniques for analyses [3,4,[19][20][21][22][23]. The matrix effects with the method were reasonably tolerable.…”