A system capable of highly sensitive measurement of material concentration values in a sample using an optical spectroscopic method is disclosed. The system utilizes high-speed data acquisition and high resolution sampling of the raw signals output by the sensors with reduced total channel counts, and performs frequency analysis of the signals using the Fourier transform method to process all sensor channels in parallel. When each sensor is targeting the detection of some certain materials at some certain frequencies, the system is capable of simultaneous detection of multiple materials of interest in the sample with high measurement sensitivity and high speed.