This study aims to investigate the use of La0.6Sr0.4Co0.2Fe0.8O3 as a Prospective anode material that can operate directly off methane fuel. The reaction of methane over the material has been investigated using a novel measurement system to obtain simultaneous catalytic and gravimetric information. This gravimetric system relies on sensing the change in the natural frequency of a quartz tube that houses the catalyst sample and allows a wide range of in-situ gravimetric experiments to be performed. The weight loss suffered by the catalyst indicates some potential degree of thermal instability with the reduction of oxide occurring as vacancies are produced. The results effectively show how increasing defect concentration effects catalytic activity and selectivity during reaction over a LSCFO oxide surface.