Determination of chromium(III) and chromium(VI) in mineral water by bidirectional electrostacking and electrothermal atomic absorption spectrometry

作者：He YZ; Cervera ML; Pastor A^*; de la Guardia M

来源：Analytica Chimica Acta, 2001, 447(1-2): 135-142.

DOI：10.1016/S0003-2670(01)01296-X

• chromium speciation
• bidirectional electrostacking
• electrothermal atomic absorption
• mineral water

A feasibility investigation was carried out on the use of bidirectional electrostacking for simultaneous separation and pre-concentration of Cr(III) and Cr(VI) and their electrothermal atomic absorption spectrometry (ETAAS) determination. The bidirectional electrostacking manifold was improved, and the effects of sample tube cross-section and electrostacking time on the pre-concentration factor were investigated. Results indicate that the sample tube cross-section and electrostacking time are the main influence factors on the electrostacking pre-concentration, as well as the electric field strength and ionic mobility. The method developed was suitable for the simultaneous separation and pre-concentration of micro- or trace cations and anions in low conductivity sample solutions. The dynamic calibration range for both, Cr(III) and Cr(VI), was from 0.5 to 10 mug l(-1) using 20 mul sample volume and ETAAS determination. Standard addition method was used for the pre-concentration of Cr(III) and Cr(VI) in electrostacking procedure. The amounts of 100 ng l(-1) Cr(III) and Cr(VI) were added into one of twin samples, which were pre-concentrated in parallel, for the pre-concentration factor calculation. The limit of detection for Cr(III) and Cr(VI) was 6 and 5 ng l(-1), respectively, for three times standard deviation (S.D.) of blank values (n = 7) and 10 min electrostacking, providing pre-concentration factors of the order of 10 times. The method was applied to analyze a certified reference material of simulated fresh water, and results were coincident with its certified value.

• 出版日期2001-11-26
• 单位中国科学技术大学