Solid‐Contact Sensor Based on Molecularly Imprinted Polymers (MIPs) for Direct Potentiometric Assessment of 2,4,6‐Trichlorophenol as a Persistent Organic Pollutant

Abstract

Abstract2,4,6‐trichlorophenol (TCP) is regarded as a very harmful persistent organic pollutant. It is prohibited by the US EPA due to its stability, possible toxicity, and substantial carcinogenicity, which could result in long‐term harm to both the environment and living things. A novel solid‐contact electrode (SCE) is fabricated and characterized for potentiometric determination of 2,4,6‐trichlorophenol (2,4,6‐TCP). Molecularly imprinted trichlorophenol polymer (MIP) beads are used as a recognition receptor for potentiometric determination of this persistent organic pollutant. The MIPs are synthesized using 4‐vinyl pyridine (4‐VP) and N,N′‐Methylene bis(acrylamide) (N,N‐MBAA) as functional monomer and cross‐linking agent, respectively. They are embedded in a selective polyvinyl chloride (PVC) membrane on the top of multi‐walled carbon nanotubes (MWCNTs), which is used as an ion to electron transducer. The SCE exhibits a Nernstian response with a slope of −55.4±2.1 mV/decade (R2=0.999) over the concentration range of 8.0×10−6 to 1.0×10−4 M, a detection limit of 5.0×10−7 M (0.98 μg/mL), and a response time of <10 s. Using electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP), the suggested SCE′s interfacial capacitance is measured. The interfacial capacitance was increased using MWCNTs and reached 39.7 μF. Also, it prevented the undesirable thin water layer from forming between the conducting glassy carbon (GC) substrate and the sensing membrane. As a result, potential stability is improved, and membrane delamination is avoided. The suggested SCE had a wide range of applications for monitoring TCP in various environmental samples because of the high selectivity, sensitivity, and possible stability that were attained.