6 Li Atom Percentage Determination by Atomic Absorption–Emission Spectrometry Using a Natural Lithium Hollow Cathode Lamp

Abstract

A simple method has been developed for the determination of ⁶Li atom % using combined atomic emission–absorption spectrometry employing a commonly available natural lithium hollow cathode lamp. Unlike in previous practice, there is no need for specially fabricated and high cost ⁶Li and ⁷Li monoisotopic lamps in this method. The method requires adjustment of total lithium contents of the sample, i.e., ⁶Li + ⁷Li, to 2 μg-mL⁻¹ based upon atomic emission spectroscopy (AES) (C_aes) against a 2 μg-mL⁻¹ natural lithium standard. The concentration of the sample was then analyzed by atomic absorption spectroscopy (AAS) measurements (C_aas). The difference between the concentration measured by AES and AAS, i.e., C_aes — C_aas, was calculated. The magnitude of the difference was found to be a function of ⁶Li fraction in the sample. A calibration curve was constructed by plotting ⁶Li atom % versus [(C_aes — C_aas)/C_aes] X 100. ⁶Li atom % of an unknown sample can be evaluated by putting its [(C_aes — C_aas)/C_aes] X 100 value in the calibration curve. The method is fast, convenient, and precise.