Determination of fluorine in milk and water via molecular absorption of barium monofluoride by high-resolution continuum source atomic absorption spectrometer

This study describes the determination of fluorine evaluating the molecular absorption of barium monofluoride (BaF) at the rotational lines of 495.088 and 495.263 nm simultaneously using a high-resolution continuum source electrothermal atomic absorption spectrometer. Upon pipetting of samples together with Ba as its nitrate, BaF was generated in the gas-phase of the atomizer. All experiments were performed using pyrolytically coated graphite tubes/platforms and applying 900 °C for pyrolysis and 2200 °C for vaporization. In the presence of 50 μg of Ba, a perfect linearity up to 0.1 μg of F was maintained. The limit of detection and characteristic mass of the method were 0.105 ng and 0.055 ng of F, respectively. The F concentration of a standard waste water sample was found in the uncertainty limits of its certified value as well as spike additions were quantitatively recovered. Finally, F concentrations in various water and milk samples sold in markets were determined.