A new approach for calibration of laser ablation inductively coupled plasma mass spectrometry using thin layers of spiked agarose gels as references.
Calibration of analytical methods using laser ablation for sample introduction is often problematic. The availability of matrix-adapted standard materials is a crucial factor in the analysis of biological samples in particular. In this work a method for preparation of thin-film references for LA-ICP-MS is presented which is inexpensive, relatively simple and generally practicable. Aqueous solutions of agarose spiked with defined amounts of the analytes were cast on a carrier and then dried. When the thin-film references were characterized the average thickness of the films was 0.03 mm in the centre of the film and the relative standard deviation was 8%. Nebulization ICP-MS analysis after acid digestion of the agarose film was used to investigate the effectiveness of the spiking procedure. Recovery of the spiked elements was frequently in the range 90-110% (for rare earth elements 97-102%). Laser ablation ICP-MS analysis was used to investigate the distribution of the spiked elements in the film. When the laser was scanned across the gel the measured intensities were not constant, but had a peak-shaped profile with a flat top. Use of this flat-top region for analytical purposes, after its characterization by laser ablation ICP-MS, is proposed. Analysis of cell cultures was carried out by direct laser ablation-ICP-MS with the calibration method described. The results were in accordance with values previously achieved by nebulization ICP-MS.
UFZ-Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany. Ha-Jo.Staerk@ufz.de
H-J
HJ
Stärk
Rainer
R
Wennrich