Selenium measurement in human plasma with Zeeman effect electrothermal atomic absorption spectrometry: sample stability and calibration method

The dual aim of the present study is the investigation of the stability of plasma samples for selenium determination with time and temperature and the assessment of the calibration method. A comparative study is performed, using two calibration methods: standard addition to each sample and matrix matched curve. ndings show that, in general, significant differences in the selenium content are observed when comparing the results obtained with these two calibration methods. Plasma samples stored at −20 °C are stable relative to the selenium content for a period of at least one year.