An interdigitated ISFET-type sensor based on LPCVD grown graphene for ultrasensitive detection of carbaryl.

Consider advances are being made to develop new technologies capable of fast in-situ tracing of agricultural toxins. In this work, we reported a simple carbaryl sensor with very high sensitivity using graphene interdigitated ion selective field effect transistor (ISFET). The graphene films were first prepared on polycrystalline copper foil by a low-pressure chemical vapor deposition method, and then transferred onto the interdigitated electrodes of ISFETs by a chemical etching technique. The biorecognition is based on the enzymatic inhibition of carbaryl towards urease. As expected, the weaker enzymatic activity of urease in addition of carbaryl would result in the weaker current response. It was demonstrated that the interdigitated ISFET sensor could achieve high sensitivity to detect carbaryl as low as 10 −8  μg mL −1 and the current response of the device showed a good linearity against the logarithm of carbaryl concentration C carbaryl with a regression equation ΔI ds  = −0.4 − 0.6 logC carbaryl (mA) (R 2  = 0.99) in the concentration range from 2.58 × 10 −7 to 2.58 × 10 −2  μg mL −1 . In conlusion, such convenient graphene-based ISFET configuration could be advantageously extended for on-line screening of other pesticide and herbicide agents. [ABSTRACT FROM AUTHOR]