An integrated cantilever sensor array system that accurately detects and measures the presence of target substances in various environmental conditions. The integrated cantilever sensor array system comprises a cantilever sensor measurement head, a cantilever sensor system for measuring the oscillatory properties of the cantilevers and a measurement chamber. The measurement head includes a cantilever array having at least one cantilever, a light source and a detector positioned to detect incoming light reflected by the cantilevers within the cantilever array. The cantilever sensor system measures the oscillatory properties generated by the cantilevers within the cantilever array. The system includes the cantilever array and a detection system that measures a signal related to the bending of the cantilever. In addition, optional components such as a high frequency clock, Q-Control, may be added to more accurately measure the oscillation of the cantilevers within the cantilever array. The measurement chamber includes a flow cell, a cantilever sensor array mounted within the flow cell. The flow cell is designed to minimize dead volume and unwanted air bubbles within the cell, which may reduce accuracy of measurement.