Determination of Cesium in Foods by Atomic Absorption Spectrometry Based on Background-correction Using Zeeman Splitted Spectrum

The demand to measure the concentration of cesium is increasing. This is because such R&D as an adsorbent or a resin for removing radioactive cesium, and a shift of cesium to food is flourishing. The measurement conditions of cesium with atomic absorption spectrometry based on background-correction using Zeeman splitted spectrum has been optimized. In flame atomic absorption method, the addition of potassium nitrate (5000 mg L−1 as potassium) as an ionization inhibitor improved the sensitivity because the ionization of cesium was controlled. The detection limit (3σ) of cesium by this method was 0.04 mg L−1. In electrothermal atomic absorption method, 1000 mg L−1 potassium tungstate as a matrix modifier improved the linearity of the calibration curve and the sensitivity of cesium. The detection limit (3σ) of cesium by this method was 0.18 μg L−1. The proposed method was applied to the determination of cesium in food reference materials. The analytical results were in good agreement with certified values.