Calcium Phosphate Sequestering Phosphopeptide from Casein

Abstract

A method is described for the enrichment of CO/sub 2/ obtained from original archeolcgical specimens following reduction to CO. The CO enrichment is derived from the O/sup 18/ abundance. For the activity measurements, the enriched CO is oxidized again by leading it over CuO. Enrichment by a factor at 16 takes about 2 months, but shifts the limit of counting to about 70,000 years. Results are reported from measurements on samples of recent carbon dioxide diluted with a known amount of inactive CO/sup 2/, dead CO/sub 2/ from anthracite, and wood from a well-exposed profile at Amersfoort which was found to have an age of 54,000 plus or minus 1100 years. (C.H.)