Solid-contact potentiometric sensors for reliable automatic quantification of 2,4-dichlorophenol (2,4-DCP) as a food taint

Sensitive, selective, and simple solid-contact potentiometric sensors were fabricated and characterized for 2,4-dichlorophenol (2,4-DCP) quantification. Membrane sensors based on the use of tridodecylmethylammonium chloride (TDMAC) and Aliquat 336 as anion exchangers were distributed in plasticized polyvinyl chloride (PVC) matrix. They revealed super-Nernstian responses with slopes of −70.3 and −78.2 over linear ranges 5.8 × 10−7-1.0 × 10−3 M and 3.3 × 10−6-1.0 × 10−3 M and with detection limits of 0.07 and 0.11 µg ml−1, for TDMAC and Aliquat 336, respectively. The sensors were compared with conventional sensors. The effect of plasticizer on the potentiometric response and diverse foreign common ions effect were examined. Sensors of both types showed a long life span, good selectivity for 2,4-DCP over a wide assortment of other common ions, long-term stability, high reproducibility, and rapid response. Validation tests illustrated good performance characteristics of the recommended sensors by evaluating the lower detection limit, range, accuracy, precision, repeatability, and between-day-variability. The sensors were effectively applied for the persistent monitoring of 2,4-DCP using a flow injection system. The sensors were applied to the 2,4-DCP potentiometric determination in spiked urine and fish samples. Recoveries ranged from 90% to 110%.