Determination of thiocyanate by carbonyl sulphide (OCS) generation and gas-phase molecular absorption spectrometry

A method for determination of thiocyanate by gas-phase molecular absorption spectrometry is described. The proposed method is based on the continuous generation of carbonyl sulphide and preconcentration in a liquid nitrogen trap. Later, the product is volatilised and the absorbance at 224 nm is measured. Under the optimised conditions, the calibration graph was linear for 2–80 μg ml−1, with a detection limit of 1 μg ml−1. No metal ions interfered. The method was tested with saliva samples from non-smokers and smokers; the results show that it is possible to distinguish between these two categories of individuals.