Synthesis of 14C and 35S labelled carbonyl sulfide

Carbonyl sulfide (COS) was prepared by a replacement reaction from potassium thiocyanate (KSCN) in 50% sulfuric acid. 14C-COS or 35S-COS can be prepared by the same method, depending on the position of the label in the starting KSCN. The yield of the final product is in excess of 60%, and radiochemical purity was 99.5%.