on the electrode surface with a cuprophane membrane and an o ring one tenth ml of 2 5 g dl tactic acid is added to adjust the zero hydrogen peroxide tension the chamber 5 is washed and refilled with 4 9 ml buffer to adjust span when equilibrium is achieved 0 1 ml of standard is used to develop the calibration curve the sample is added and the concentration determined from the calibration curve it was determined that the optimum ph range is from 6 5 to 8 0 fig9 and that the buffer concentration range of from 0 05m to 0 1m had no influence on the lactate oxidase membrane fig1 the membrane can perform 200 tests on serum samples while still retaining 30 of its original activity fig1 the membrane stored in glycerol bufferate at 4 u00b0 c has activity for over four months the lactate oxidase membrane prepared in this manner can be applied not only to a tactic acid enzyme electrode for clinical fermentation and food industries but also for tactic acid production a hydrophilic polypropylene membrane is cut into an 11 mm id ring the shaped membrane is washed with 0 1m sodium chloride and distilled water dried and stored in a dessicator for later use twenty nine mg of 1 glutamate decarboxylase ec 4 1 1 15 sigma co usa is dissolved in 1 ml of 0 02m citric buffer at ph 4 5.