Determination of carbon-14 in solutions of C+14-labeled materials by means of a proportional counter

Abstract

A st ud y is r eported of t he detennina t,io n of car bon-1 4 in CH-Iabeled su bsta nces by co unt ing, wi th a proport ional gas-fl ow co un ter, t h E' r a dioact ive disin tegrations ari sing from a m ateri al t hat is di ssol ve d in a s uitable solv cnt. A number of solven t.s wer e found to bc satisfactor y . F orm amide is recomm ended for t hc assay of carb oh ydr9.tes a nd other m aterials wi th w hich it is a comp atibl e sol vent. Eth. vlene glyco l is s ui table for the assay of highl y al kali ne substances, a nd, in co nj unction with sequesterin g age nts, for t he assay of a lk a linc car th car bonates. Other useful sol ve nt s ar e dim eth yl fo rm amide and 90-pcr ce nt phosp horic acid . T he co unt ing effi ciency in diffarent solvents was found to be inversely p roport ional to th e density o f t he solu tio n a nd hi ghly rep rod ucible. The st ud y sh ows that solu tio ns of CI4-labeled m ate rials can be co unted easil y and p rec ise!.v with a p roport io na l counter.