The paper presents some investigation on material properties which are candidates for a gas sensor. The best choice was semiconducting oxides such as WO3, CuO, SnO2 , TiO2. The materials properties were optimized to obtain the most sensitive gas sensor. Gas sensor matrix was used to build portable device for non-invasive diabetes diagnosis. The design of measuring device for glucose level in blood from the exhaled air gas content is presented. The components of device such as gas preconcentrator, gas sensor, integrated gas sensor matrix and a measuring method are described. The advantages of such a device were presented for portable, personal model as well as a hospital once.