A detection method for enabling gas composition observation during fuel cell system start-up is described. In one embodiment, the method includes initiating a flow of hydrogen to the anode to pressurize the anode; opening an anode flow valve; determining if an anode pressure exceeds an anode pressure threshold; enabling anode flow set point detection after a first predetermined time if the anode pressure exceeds the anode pressure threshold; monitoring an anode flow set point using the anode flow set point detection; determining if the anode flow set point exceeds an anode flow set point threshold; and closing the anode flow valve after a second predetermined time if the anode flow set point exceeds the anode flow set point threshold.