M. Scholz et G. Gescheidt, A QUANTITATIVE STUDY OF ENRICHMENT OF K-ION PAIRS GENERATED BY SODIUMREDUCTION( IN RADICAL), Journal of the Chemical Society, Chemical Communications, (2), 1994, pp. 239-240
ESR spectroscopy and atomic absorption measurements establish that Kenrichment up to four orders of magnitude may occur when reduction rea
ctions are performed using even highly pure Na sources.