1-(2-Pyridylazo-2-naphthol), PAN, has been introduced and extensively employed as a reagent in radioanalytical chemistry in our laboratories. An earlier communication dealt with the determination of micro amounts of Cu(II) by displacement of labelled zinc from Zn-PAN complexl'. The present work is intended to develop a similar method employing Zn-PAN complex for the determination of mercury(II)...