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Abstract
A novel sequential injection on-line column preconcentration method for ultra-trace cobalt determination by electrothermal atomic absorption spectrometry (ETAAS) using poly(etheretherketone) (PEEK) turnings as sorbent material was developed. The method was based on the on-line chelate complex formation and retention of target analyte with ammonium pyrrolidine dithiocarbamate (APDC) on the surface of PEEK-turnings and elution with methyl isobutyl ketone (MIBK). A 40 µL fraction of MIBK containing the bulk of analyte complex introduced directly into the transversely heated graphite tube atomizer of ETAAS for quantification. Acidity of sample solution, chelating reagent concentration, and preconcentration time were investigated and optimized separately, while all other factors were optimized by full factorial design optimization methodology. The significance of the variables and their interactions was estimated by employing analysis of variance (ANOVA) and Pareto chart. Under the optimum conditions the enhancement factor for cobalt determination was 60. The detection limit was 6 ng L−1 and the precision expressed as relative standard deviation (RSD) was 3.5% at 0.1 µg L−1 Co(II) concentration level, respectively. The proposed method was evaluated by analyzing water certified reference materials and spiked environmental samples.
Acknowledgments
This paper is part of a special issue organized by Dr. Nikolaos Thomaidis and Dr. Antony C. Calokerinos from research presented at the Aegean Analytical Chemistry Days Conference in Lesvos, Greece on 29 September–3 October 2010.
Notes
a Sample propulsion with flow rate, (160 µL s−1); V, valve of syringe pump; MV, multi-position valve; SP, syringe pump; P, peristaltic pump; GF, graphite furnace of ETAAS.
a Mean value ± standard deviation based on three replicate measurements.