Abstract: A method for quantitating analyte in a process gas stream using a gas sensor system having a plurality of sensor cells containing multiple semiconducting metal oxide gas sensors. The method includes calibrating and baselining each cell, and flowing a process gas through each cell for a respective time interval. Sensor outputs for each cell are processed to determine the amount of analyte in the process gas for each time interval. Then, the analyte amounts determined for each time interval are added to determine a total analyte quantity. In a first embodiment, all of the cells are calibrated simultaneously prior to any exposure to process gas. In a second embodiment, the cells can be repeatedly and sequentially exposed to process gas over additional time intervals. In this case, each cell is calibrated prior to each of its time intervals.