Selective and sensitive onsite detection of phthalates in common solvents

Phthalates, which are proven to have adverse health effects, are globally restricted for use in all kinds of plastics through various regulations. Although there are laboratory based techniques for phthalate detection, there is a pressing need for a field based technique so samples can be pre-screened. Here, we report a molecularly imprinted polymer (MIP) functionalized extended gate field effect transistor (EGFET) as a field sensor to identify di-2-ethlyhexyl phthalate (DEHP), which is the one of the most commonly used phthalate. In DI water, DEHP is detected at the extremely low concentration of 25 μg/L while exhibiting excellent selectivity. We are able to tune the linear dynamic range of the sensor by synthesizing the MIP with a different monomer-to-template ratio and by choice of the functional monomer. Finally, the sensor is calibrated for DEHP in artificial saliva at sub 50 μg/L, showing applicability in phthalate migration tests, which are used in assessing the safety of plastic toys. Furthermore, our sensor platform can be further extended to identify other phthalates as fast pre-screening tool.