Direct detection of antimony in environmental and biological samples at trace concentrations by laser-induced fluorescence in graphite furnace with an intensified charge coupled device

Abstract

The technique of laser-induced fluorescence in graphite furnace (LIF-GF) with intensified charge coupled device (ICCD) detection was used for the detection of Sb at pg ml^–1 concentrations in various biological and environmental samples. The ICCD detector permits the simultaneous multi-channel detection of large fluorescence wavelength regions, which gives the user the possibility to control and correct for various background signals (which is important when complex environmental and biological samples are to be analysed). The detection limit for Sb in a pure water solution was found to be 5 fg. Antimony was directly detected in pure aqueous solutions down to fg ml^–1 concentrations. A variety of aqueous and solid environmental and biological samples were investigated with respect to their Sb content. Good agreement between the measured and certified Sb contents (at pg ml^–1–ng ml^–1 levels) was obtained for various certified reference materials, viz., marine sediments (MESS-1 and BCSS-1) and riverine water (SLRS-2). Measurements of the Sb content in non-certified natural drinking water, estuarine water reference material (SLEW-1), serum reference material (Seronorm), and whole blood of healthy Swedish people were also performed. After a thorough investigation and elimination of various sources of contamination (regarding sampling and sample storage), typical levels of Sb in human whole blood at or below several tens of pg ml^–1 were obtained. These levels are significantly lower than previously established values of the normal Sb content in human blood. The detection limit for Sb in human whole blood was close to that of pure water.