Pre-concentration of carbon-14 labelled thiocyanate by ion exchange

Abstract

A ten-sample pre-concentration method for determining carbon-14 labelled thiocyanate in oil field production water is described with a limit of detection of 0.013 parts per 10¹²(0.5 Bq l^–1) in production water containing up to 10% NaCl. The carbon-14 labelled thiocyanate is concentrated on an anion-exchange resin before being eluted with 2.8 M sodium perchlorate and counted by liquid scintillation. All the carbon-14 labelled thiocyanate in a 170-ml sample can be concentrated to 10 ml. The average relative standard deviation in the range 0.5–17 Bq l^–1 is 6%. The method can be used to process 20 samples per day.