Garlic tissue cells are employed for the conversion of L-asparagine into ammonia. An ammonia gas electrode is used as a detector. The effect of pH, buffer solution, temperature and life time of electrode to have used were investigated in order to optimize the electrode response. The combination of L-asparaginase in garlic tissue cells and the gas electrode response linearly to Lasparagine over the concentration range 1.0$ imes$10$^{-4}$~1.0$ imes$10$^{-1}$ M with a slope of 72.0 mV/decade and is selective with respect to other L-amino acids.