Quantification of total chromium and hexavalent chromium in UHT milk by ETAAS

• Type: Article in International Scientific Journal
• Date: 1998

Authors

Lameiras, J (Author) Other; Soares, ME (Author) Other; Bastos, ML (Author) FFUP; Ferreira, M (Author) Other

Journal

Title: The Analyst

Vol. 123

Pages: 2091-2095

ISSN: 0003-2654

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 29 Citations

Scopus - 31 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-001-6YD

DOI: 10.1039/a804700f

Abstract (EN): Procedures for the quantification of total chromium and hexavalent chromium in UHT milk samples are presented. Total chromium was determined directly in milk with the: addition of a surfactant and a mixture of Pd and Mg as a chemical modifier. For the selective separation of hexavalent chromium, the sample pre-treatment consisted in precipitation of proteins and elution of the supernatant through a Chromabond NH2 column. The metal was eluted with nitric acid. Both total chromium and hexavalent chromium were evaluated by atomic absorption spectrometry with electrothermal atomization using the same instrumental conditions. The detection limits were 0.2 and 0.15 mu g l(-1) for total chromium and hexavalent chromium, respectively. The linearity ranges under the optimized conditions were 0.2-20 and 0.15-50 mu g l(-1). For total chromium the precision was 4.9 and 5.7% for the analytical and the over-all procedure, respectively, and for hexavalent chromium 4.3 and 4.9%, respectively. The validation of both procedures was performed by the standard additions method and the recoveries were higher than 93% in all cases. For total chromium, a certified reference material was also used to validate the methodology. The methods were applied to the determination of total chromium and hexavalent chromium in 60 UHT milk samples.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5