Determination of uranium concentration in a single hair strand by LAICPMS applying continuous and single pulse ablation

A longitudinal distribution of uranium content in a single hair strand, obtained by both single pulse and continuous run laser ablation coupled to ICPMS is presented. Monitoring the uranium concentration profile along the hair strand reveals a three day period occupational exposure event. Limit of detection (LOD) for uranium is 19 ng g^-1 for the continuous ablation mode, and 700 ng g^-1 for a single laser pulse. Accuracy and precision are presented as well. The use of image processing of the laser trace (single pulse mode) on the single hair strand for improvement of the signal stability, and understanding intensity changes as well, is demonstrated. Two commercial ICPMS systems were used for the quantitative analysis. One was equipped with a liquid sample introduction system (for digested samples), while the other was equipped with a laser ablation system and was used for the direct determination of uranium in hair samples. The calibration procedure is discussed, along with a detailed examination of data output from the hair strand scan.