The challenges of Se quantification in bean samples using line and continuum sources atomic absorption spectrometry

Area of Science:

• Analytical Chemistry
• Environmental Science
• Food Science

Background:

• Selenium (Se) is an essential trace element, but its accurate determination in food matrices like beans presents analytical challenges.
• Existing methods using graphite furnace atomic absorption spectrometry (GF-AAS) struggle with low selenium concentrations and spectral interferences.

Purpose of the Study:

• To evaluate the challenges of selenium determination in bean samples using high-resolution continuum source (HR-CS-GF-AAS) and line source (LS-GF-AAS) techniques.
• To optimize chemical modifiers (Ir, Ru, Pd/Mg nitrates) for improved selenium quantification.
• To compare the performance of HR-CS-GF-AAS and LS-GF-AAS with in situ trapping hydride generation for selenium analysis.

Main Methods:

• Optimization of chemical modifiers (Ir, Ru, Pd/Mg nitrates) for selenium determination.
• Application of high-resolution continuum source Graphite Furnace Atomic Absorption Spectrometry (HR-CS-GF-AAS).
• Application of line source Graphite Furnace Atomic Absorption Spectrometry (LS-GF-AAS) with in situ trapping hydride generation.

Main Results:

• Selenium could not be accurately quantified at levels below 5 ng g^-1 using HR-CS-GF-AAS.
• Spectral interferences from PO, NO molecular bands, and iron lines were observed.
• HR-CS-GF-AAS exhibited high limits of detection (24-33 ng g^-1) due to low continuum source energy at 196.026 nm.
• In situ trapping hydride generation LS-GF-AAS achieved a significantly lower limit of detection of 30 pg g^-1 with an Ir modifier.

Conclusions:

• Accurate selenium determination below 5 ng g^-1 in bean samples is difficult with HR-CS-GF-AAS due to spectral interferences and instrumental limitations.
• LS-GF-AAS coupled with in situ trapping hydride generation offers superior sensitivity and lower detection limits for selenium analysis in complex matrices.