NEW DEVELOPMENT FOR THE DIRECT CO2 ABSORPTION METHOD FOR RADIOCARBON ANALYSIS

A method for analysis of radiocarbon using direct absorption into an a lkaline organic amine, and subsequent LSC, was introduced by Qureshi e t al. (1989). This paper describes several modifications to that origi nal idea by development of a recirculating closed-system and use of bl adder system to store and deliver CO2. The modifications have increase d the precision and useability of the method which ensures saturation of the Carbosorb and allows up to 5 samples to be prepared for countin g per day per extraction line. Organic samples can also be prepared fo r LSC by using a Parr bomb which is much more efficient than conventio nal combustion in a stream of oxygen. Overall, the method has slightly lower precision than the benzene method but, in many instances, count ing statistics are much less than the overall uncertainty contributed by inter- and intra-sample variability. Therefore, for applications in many instances where radiocarbon is used as a dating tool or as a tra cer, the Carbosorb method now provides a rapid and less expensive alte rnative.