The determination of cyanide and sulfide in the trace range requires an alkali eluent and amperometric detection. This Application Note describes a new column/eluent combination for optimized separation. The combination consists of the Metrosep A Supp 10 - 100/2.0 Microbore Column and a sodium hydroxide eluent that contains traces of EDTA for the complexation of the transition metals. This yields a better peak shape and detection limits below 0.05 µg/L.