Hydrogen is used in a number of areas, from industrial processes such as pesticide production and the removal of sulfur from petrochemical products to its use as a fuel and in power generation. To ensure the quality of hydrogen, standards such as ISO 14687 and GB/T 37244 have been produced which specify the maximum content of certain compounds in fuel hydrogen gas. As such, it is of great importance that hydrogen gas refiners and those using hydrogen gas in various processes have access to a method which allows for quick, accurate and sensitive detection of these compounds. This application note will detail the quantification of Helium in Hydrogen using a thermal conductivity detector (TCD) with a nitrogen carrier gas.