The effect of the O2-scavenger on glucose sensing in the self-filling sensor strips was assessed by means of chronocoulometry (Figure ) over a wide glucose concentration range pertinent to blood glucose levels (Figure ). The charge obtained under inert atmosphere was used for normalization of the charge obtained under air and in the presence of the O2 scavenger (Figure ). The charges measured in ambient air without O2-scavenger were lower than those measured under inert atmosphere, particularly at glucose concentrations below 20 mM. The effect was less pronounced at higher concentration due to the limited availability of O2 in the small volume capillary and the hindered replenishment of O2 from ambient air through the capillary channel. In presence of the O2 scavenger, the charge values show excellent agreement with those obtained under inert atmosphere except for the glucose concentration in the low millimolar range. The time needed for dissolution of all the components of the O2-scavenger may account for this effect. Nevertheless, the glucose reading in presence of the scavenger are highly accurate in the normal concentration range for human (40) (4 to 10 mmol L -1 , green area in Figure and) and in the high concentration range which are the most relevant to diabetes management with respect to need for insulin intake . The biosensor with O2 scavenger exhibits a sensitivity of 114.5 µC mM -1 , with a detection limit of 0.72 mM (Figure ). average while the coulometric mode has an average standard deviation of 7.5 % in the temperature range from 5 to 45 °C (Table ). The amperometric operation has a fast response time but is more dependent on external parameters such as temperature which influence the enzyme activity or mass transport and thus lead to fluctuation in the current reading. In contrast, the electrical charge extracted in the coulometric mode is highly reproducible, regardless of the external temperature. This demonstrates the possibility for calibration-free sensing with oxidase based sensor in ambient air.