Preliminary Screening of Potential GenX in Groundwater near PFAS Factories via a Size-Gated Sensitizing Sensor

Developing on-site preliminary screening technologies for the potential PFAS alternative, GenX, in groundwater is crucial to overcoming the limitations of traditional methods and advancing environmental monitoring. Herein, a highly sensitive and selective electrochemical molecularly imprinted (E-MIP) sensor was fabricated for the preliminary screening of GenX in groundwater near PFAS factories. Its surface molecularly imprinted films form a gate-controlled structure that captures GenX via size steric hindrance, while low-defect Joule-heated carbon black and a dual-signal strategy synergistically enhance the electrode interface signal conversion. When GenX entered the electrode interface through size screening, it specifically bound to the imprinting sites, triggering electron transfer changes and generating a superimposed signal-off sensing mode. The optimized sensing platform exhibited high sensitivity over 1 ng/L to 10 μg/L, with a detection limit of 0.233 ng/L. Applied to actual groundwater samples, it can effectively distinguish positive/negative samples and showed a strong correlation with LC-MS/MS results (R2 = 0.993, p < 0.0001), highlighting its practical accuracy. This E-MIP sensor can be deployed as an environmental probe around the groundwater in PFAS factories for preliminary purposes, significantly facilitating GenX control.