Flashlamp continuum AAS: time resolved spectra

Abstract

For flashlamp continuum atomic absorption spectrometry (FLACAAS), a continuum spectrum of high intensity throughout the entire UV-VIS spectral range is provided typically by xenon flashlamps. These lamps offer high intensity in the UV which is however strongly fluctuating. This drawback may be compensated for by using the simultaneously recorded spectral vicinity of the absorption line for correction. In order to accomplish this type of measurement, a high resolution spectrometer and a multipixel photodetector are required. This paper describes such a combination of an échelle spectrometer and a linear-array charge coupled device (CCD) detector with a graphite furnace atomizer and a xenon flashlamp for AAS-measurements at a repetition rate of 10 Hz. The determination of thallium (absorption line 276.787 nm) in natural seawater in the presence of palladium (interfering line 276.309 nm) used as modifier, demonstrates the effective background correction and the possibility for sensitive analysis of complex samples by time-resolved continuum AAS. The characteristic mass of thallium was determined to be 28 pg, the limit of detection in seawater amounts to 20 µg l^–1.