On-line separation and preconcentration of chromium species in seawater

J. Posta, A. Alimonti, F. Petrucci, S. Caroli

Research output: Contribution to journalArticle

92 Citations (Scopus)

Abstract

A study was undertaken to ascertain the analytical capabilities of combined HPLC-ICP-AES with ultrasonic nebulization or HPLC-ICP-MS systems to perform on-line separation of Cr(III)-Cr(VI) and on-line preconcentration of Cr(VI). Tetrabutylammonium bromide was used as the ion-pair forming agent and a reverse phase C18 column was used for separation. By optimizing the conditions of separation and preconcentration as well as plasma parameters a method could be developed for the determination of Cr(III) and Cr(VI) in seawater by HPLC-ICP-AES with ultrasonic nebulization. In this matrix detection limits (3σ criterion) turned out to be 4.6 ng/ml for Cr(III) and 3.7 ng/ml for Cr(VI), while the RSD is 2%-3% at the level of 100 ng/ml Cr. As the preconcentration of Cr(VI) is regarded, the detection limit of ICP-AES depends, among others, on the sample volume loaded onto the column. It resulted to be 0.20 ng/ml for an initial volume of 2 ml, while the RSD at 10 ng/ml Cr(VI) was ±3.8%. On the other hand, the high salinity of seawater and C content of the separation eluent pose serious problems with ICP-MS detection. In fact, in this matrix only Cr(VI) preconcentration was achieved with a detection limit of 0.12 ng/ml for Cr(VI) (initial volume 2 ml). Due to isobaric interferences, the isotope at mass 50 (relative abundance 4.31%) was preferred.

Original languageEnglish
Pages (from-to)185-193
Number of pages9
JournalAnalytica Chimica Acta
Volume325
Issue number3
DOIs
Publication statusPublished - May 30 1996

Keywords

  • Chromium specation
  • Chromium(VI) preconcentration
  • Inductively coupled plasma aotmic emission spectrometry
  • Inductively coupled plasma mass spectrometry
  • Seawater
  • Ultrasonic nebulization

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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