a method for determining the amount of a chemical species in a sample , in particular the amount of weak acid dissociable cyanide or total cyanide in a sample , and an apparatus for performing said method . the method comprises the steps of : i ) treating the sample to liberate the chemical species into a gaseous stream ; ii ) directing the gaseous stream to a scrubber ; iii ) absorbing the chemical species into a scrubber solution ; and iv ) determining the amount of chemical species absorbed into the scrubber solution , wherein any remaining chemical species not absorbed into the scrubber solution is directed or recirculated to the scrubber in the gaseous stream and step iii ) is repeated to increase absorption of the chemical species prior to performing step iv ).