6Li atom percentage determination by atomic absorption-emission spectrometry using a natural lithium hollow cathode lamp.

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 microg x mL(-1) based upon atomic emission spectroscopy (AES) (C(aes)) against a 2 microg x 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.