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A pulse chromatographic procedure has been developed for the measurement of the surface areas of catalytic metals by carbon monoxide chemisorption. This procedure consists of repeated injection of carbon monoxide pulses into a helium carrier gas passed over the metal surface to establish the cumulative saturation value which corresponds to irreversible chemisorption. Independent measurements made on unsupported platinum and nickel metal powders with volumetric and chromatographic surface area procedures and on supported nickel catalysts with a volumetric chemisorption procedure have established the validity of the pulse chromatographic procedure for determination of carbon monoxide chemisorption. Advantages of the pulse chromatographic procedure include the avoidance of high vacuum procedures and the avoidance of corrections for reversible physical adsorption.GAS CHEMISORPTION is an established technique commonly used for the estimation of the accessible reactive surface of metal catalysts. The gases most commonly used are hydrogen and carbon monoxide. This technique is applicable to a variety of metal catalysts which include the transition metals (iron, nickel, cobalt, and the platinum family). Volumetric gas adsorption procedures are most commonly used for chemisorption measurement. However, several recent applications have been made of chromatographic procedures (1-6).Chromatographic measurements have several attractive aspects which include:1. High vacuum procedures are avoided. 2.Measurements are made under dynamic flow conditions approximating those under which catalysts are most commonly used. In the present study, a pulse chromatographic procedure has been used to measure the chemisorption of carbon monoxide on supported nickel and unsupported nickel and platinum catalysts. This chemisorption procedure consists of repeated exposure of the catalysts to carbon monoxide pulses to establish the cumulative saturation value which corresponds to irreversible adsorption at room temperature. A comparison is made with results from measurements made with the classical volumetric procedure to establish the equivalence of the gas chemisorption values determined by the two procedures on the 1

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