Catalytic Adsorptive Stripping Voltammetric Procedure for Determination of Total Chromium in Environmental Materials

Abstract

A sensitive catalytic adsorptive stripping voltammetric procedure for determination of traces of total chromium in environmental samples is reported. The method is based on the preconcentration of a Cr(III)ÀH 2 DTPA complex by adsorption at the HMDE from an acetate buffer solution at the potential À 1.0 V vs. Ag/AgCl. Total chromium was determined as Cr(III) after reduction of Cr(VI) to Cr(III) by NaHSO 3 . In order to stabilize the signal of Cr(III) the measurements were performed at 5 8C. The calibration graph for chromium for an accumulation time of 60 s was linear in the range from 5 Â 10 À10 to 5 Â 10 À8 mol L À1 . The relative standard deviation for a chromium concentration of 1 Â 10 À8 mol L À1 was 3.9% (n ¼ 5). The detection limit for accumulation time of 60 s was about 8 Â 10 À11 mol L À1. The validation of the procedure was performed by the analysis of the certified reference materials.

Hybrid signal processing in voltammetric determination of chromium(VI)

“…The last progresses in catalytic systems of chromium applied in adsorptive stripping voltammetry were presented in Refs. [22,25,26,28,[30][31][32][33][34][35][39][40][41]. In this work determination of Cr(VI) will be done in the presence of DTPA and nitrate on the silver-amalgam electrode with a refreshable surface [28].…”

Speciation and determination of ultra trace amounts of chromium by solidified floating organic drop microextraction (SFODME) and graphite furnace atomic absorption spectrometry

“…Various analytical techniques such as atomic absorption spectrometry (AAS) [6][7][8], spectrophotometry [9], spectrofluorometry [10], stripping voltametry [11], inductively coupled plasma-atomic emission spectrometry (ICP-AES) [12], inductively coupled plasmamass spectrometry (ICP-MS) [13,14], and high performance liquid chromatography (HPLC) [15] have been frequently used for accurate determination of chromium in various samples. However, due to its good sensitivity, graphite furnace atomic absorption spectrometry (GFAAS) is one of the most extensively used techniques for the determination of trace amounts of various elements, but it suffers from matrix interferences and the direct determination of the species of the elements presented in the samples is not possible.…”

Polyethylenimine Functionalized Multi‐walled Carbon Nanotubes for Electrochemical Detection of Chromium(VI)

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1Introduction Chromium (Cr) is ah eavy metale lement which is widely used in industries like leather tanning, furnacec ooling, plating and wood preservation. WHOh as set the provisional guideline value of Cr(VI) in ground water as 50 ppb [6].T herefore, the development of sensitive analytical methods for Cr(VI) species in aqueous system is of great significance.Electrochemical technology has been one of the main techniques for analysis of Cr(VI), which is important to meet the ever-growing demando fo n-site high throughput detections.T he most widely appliede lectrochemical technique for chromium(VI) determinationi sc atalytica dsorptive stripping voltammetry (AdCSV), whichi so ften based on the preconcentration of Cr(VI) species on the electrode surface by using complexing agent [7-10].Hanging mercury drop electrodes [11][12][13][14][15],m ercuryf ilm electrodes [16,17] and bismuth film electrodes [18][19][20][21] have been used for these purposes.H owever,t hese electrodes also require nitrate ion as catalyst, and they suffer either from the interference or requiremento fr egeneration procedures for the repeatedu se of the electrodes.Recently,s ome simple and fast voltammetric techniques have been applied, whicha re based on direct reductiono fC r(VI) to Cr(III) in aa cidicm edia,w ithout any time consuming accumulation step.G old nanoparticles electrodeposited on indiumt in oxide( ITO) electrodes [22] and flower-like self-assemblies of gold nanoparticles [23] were used for the voltammetric detection of Cr(VI). Cr(VI) depending on the pH, is available in anion forms as CrO 4 2À ,H CrO 4 À ,H 2 CrO 4 or Cr 2 O 7 2À

,i s toxic, mutagenic and carcinogenic [1][2][3][4][5].T his fact leads to the strict control of Cr(VI) content.

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“…Hanging mercury drop electrodes [11][12][13][14][15],m ercuryf ilm electrodes [16,17] and bismuth film electrodes [18][19][20][21] have been used for these purposes.H owever,t hese electrodes also require nitrate ion as catalyst, and they suffer either from the interference or requiremento fr egeneration procedures for the repeatedu se of the electrodes.…”