Comparison of two methods using atomic absorption spectrometry for determination of selenium in food

This study describes and compares two methods of atomic absorption spectrometry (AAS) for the selenium (Se) analysis in food: electrothermal AAS (ET AAS) and hydride generation method of AAS (HG AAS). The accuracy of the two methods was established by analysing two biological reference materials: Wheat Flour 1567a and Bovine Liver 1577b from the National Institute of Standards and Technology, USA. Good agreement with certified values was obtained for both methods. The accuracy of ET AAS method is 109% and 103% for Wheat Flour and Bovine Liver, respectively. The respective accuracies for HG AAS method were 88% and 87%. The detection limit obtained for ET AAS was 1 microgram Se/L and for HG AAS 0.02 microgram Se/L. The repeatability of ET AAS method was 5-11% and that of HG AAS 14-17%. Both methods are similar in accuracy and repeatability, but hydride generation (HG AAS) is more sensitive than graphite furnace technique (ET AAS) for determination of selenium in food.