Another way to study Mars' Methane

Space.com has an article on a possible instrument that could measure the Martian methane and potentially determine if the source is geological or biological. The earliest such an instrument could fly would be the 2016 ESA-NASA rover, but I believe that that would be stretch. So this would like be an instrument for a late 20-teens or early 2020's rover or lander. It possible that if a Scout mission were added to the budget for the mid to late 2010's that it could carry this instrument. Such a lander might be put down in one of the three areas identified as areas of high methane concentration.