A method for calculating an amount of ammonia present in a gas sample is provided. The method includes receiving a first gas sample by a hydrogen analyzer. The first gas sample contains ammonia. The method also includes receiving a second gas sample by the hydrogen analyzer. The second gas sample is formed by eliminating ammonia from the gas sample. The method further includes measuring, by the hydrogen analyzer, an output signal for each of the first and second gas samples. The method includes calculating the amount of ammonia present in the gas sample based on the measured output signal for each of the first and second gas samples and a hydrogen error correction value.