Method development and optimization for the determination of selenium in bean and soil samples using hydride...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Geochemistry

Background:

• Selenium is an essential trace element with varying regional abundance.
• Accurate measurement of selenium in food and soil is crucial for environmental and health assessments.
• Brazil lacks comprehensive regional maps of natural selenium abundance.

Purpose of the Study:

• To establish a methodology for determining natural selenium abundance in Brazilian bean and soil samples.
• To lay the groundwork for a regional selenium abundance map of Brazil.
• To validate a sensitive analytical method for selenium determination.

Main Methods:

• Continuous-flow hydride generation electrothermal atomic absorption spectrometry (HG-ET AAS) with in situ trapping.
• Microwave-assisted acid digestion optimized for complete selenium recovery from bean and soil matrices.
• Optimization of Se(VI) to Se(IV) reduction to prevent back-oxidation.

Main Results:

• The HG-ET AAS method demonstrated high sensitivity with limits of detection and quantification at 30 ng L(-1) and 101 ng L(-1) Se, respectively.
• Method validation using certified reference materials (soybean, rice, soil, sediment) confirmed its accuracy.
• Selenium content in analyzed bean samples ranged from 5.5±0.4 to 1726±55 ng g(-1), and in soil samples from 113±6.5 to 1692±21 ng g(-1).

Conclusions:

• The developed HG-ET AAS method is suitable for sensitive and reliable determination of selenium in bean and soil samples.
• The findings provide baseline data for regional selenium mapping in Brazil.
• Further application of this method will contribute to understanding selenium distribution and its implications.