Abstract: A micro sensor device for measuring a concentration of a substance within a sample comprises an integrated sensor head having a tip portion adapted to be inserted into a sample, a light source for emitting a beam of light into and through the tip portion with the tip portion capable of interacting with a substance within a sample to produce a reflected pattern of light, and a detector for receiving the reflected pattern of light, and a body portion coupled to the integrated sensor head, the body portion comprising a processor operatively connected to the light source and the detector, the processor for controlling the light source for emitting the beam of light, for receiving the pattern of reflected light from the detector, and for processing the reflected pattern of light to determine the concentration of a substance within a sample.