AbstractRetention indices were determined for a homologous series of n‐dialkyl sulphides on three stationary phases (SE‐30, OV‐17 and XE‐60) under isothermal and linear temperature programming conditions. Under these two different GC conditions, equations were derived for each of the three stationary phases which showed the dependence of retention index on the number of carbon atoms and the boiling points for a homologous series of n‐dialkyl sulphides. The equation for the correlation isothermal retention index was shown to be applicable to the identification of n‐dialkyl sulphides using linear temperature programming. It was found that the GC behaviour of n‐dialkyl sulphides makes these compounds suitable for use as a standard series instead of n‐alkanes for the calculation of retention indices in GC analysis in which detectors insensitive to n‐alkanes are employed. The use of the homologous series of n‐dialkyl sulphides for the calculation of sulphide retention indices can be great practical importance in the microanalysis of natural compounds. We have used this method successfully in the analysis of pesticides