Sensitive metal ion sensors based on fibrous polystyrene membranes modified by polyethyleneimine

The primary goal of the present study is to develop a quartz crystal microbalance (QCM) sensor functionalized by three-dimensional sensing membranes for heavy metal ion detection. The fibrous polystyrene (PS) membranes were stabilized on the QCM electrode and modified with subsequent gold sputtering, followed by the functionalization of the sensing polyethyleneimine. The morphology and specific surface area (SSA) of the PS membranes were controllable by adjusting the weight ratios of the blend solvents of tetrafuran, N,N-dimethylformamide. The resultant sensors with optimal structure showed excellent selectivity for Cr with a detection limit of 5 ppb. Sensor sensitivity increased concurrently with both increasing PS loading and SSA on the electrode of QCM. The sensor responses showed good linearity in the 5-200 ppb concentration range. The results suggest that the fibrous membrane QCM sensors have potential for further applications in other sensors. © 2012 The Royal Society of Chemistry.