Method for the Determination of Selenium in Low-Selenium Grain and the Effect of Liming on the Uptake of Selenium by Barley and Oats
Title:
Method for the Determination of Selenium in Low-Selenium Grain and the Effect of Liming on the Uptake of Selenium by Barley and Oats
Author:
Hansson, Lena Johansson, Karin Olin, Åke Siman, Gyula
Appeared in:
Acta agriculturae Scandinavica. Section B, Soil and plant science
Paging:
Volume 44 (1994) nr. 4 pages 193-200
Year:
1994-12-01
Contents:
Selenium was determined in grain of barley and oats grown at locations distributed all over Sweden with the objective of studying the influence of liming on the selenium uptake at natural levels in the soil. The samples were taken from on-going field experiments, limed to different levels. An analytical procedure, carried out in a single test tube, was developed to cope with the low selenium concentrations in the grain. It involves combined wet/dry ashing of the organic matter, reduction to selenite by hydrochloric acid, complexation to obtain a brominated piazselenol, extraction of the complex into toluene, and finally determination by capillary gas chromatography with electron capture detection. The concentrations of selenium in the grains investigated were low, ranging from 1.5 to 16 ng g-1 dry weight. The limit of detection for a 0.1 g sample is 0.4 ng g-1, as estimated by three times the standard deviation of the blank determination (n = 34) and the absolute limit of detection for pure solutions is below 20 fg (0.5 μl injection on the column). The procedure was validated by determinations on reference materials, testing an alternate digestion procedure, and by determination using hydride generation atomic absorption spectrometry. Liming of the soil was found to have a small, but significant negative effect on plant uptake of selenium.