This International Standard specifies a procedure for determination of the mass concentration of mercuryvapour in workplace air using a method of gold-amalgam collection with analysis by either cold vapour atomicabsorption spectrometry (CVAAS) or cold vapour atomic fluorescence spectrometry (CVAFS). The procedure specifies a number of sampling methods for different applications. a) When it is known that no particulate inorganic mercury compounds are used in the workplace and that noneare produced in the processes carried out, samples of mercury vapour are collected using a pumpedsorbent tube containing porous gold-coated diatomaceous earth. Suitable sorbent tubes are commerciallyavailable or they can be made from sorbent prepared by pyro-decomposition of chloroauric acid [hydrogentetrachloroaurate(III)] sintered on diatomaceous earth. b) When both mercury vapour and particulate inorganic mercury compounds could be present in the testatmosphere, samples of mercury vapour are collected using a pumped sorbent tube fitted with a quartz fibreprefilter to remove particulate inorganic mercury compounds. If desired, the procedure described inISO17733 can be used to collect and analyse separate samples for measurement of particulate inorganicmercury compounds. c) When it is known that no elemental mercury is used in the workplace and that no mercury vapour isproduced in the processes carried out, the procedure described in ISO17733 can be used, if desired, tocollect and analyse samples for measurement of particulate inorganic mercury compounds.