A new potentionmetric photocurable membrane selective to anionic surfactants

The preparation of photocurable polymer membranes selective to anionic surf actants and their application to all-solid state ion-selective electrodes a r e reported. A preliminary trial employing CHEMFET devices is also shown. Membranes are based on a urethane-acrylate polymer, and use 2-cyanophenyl o ctyl ether (CPOE), a plasticizer compatible with the photocuring process. T hese membranes are highly selective to the anionic surfactants assayed whil e common inorganic anions did not interfere. An optimization methodology is proposed for their formulation, suited to the final application. Several m embrane compositions were obtained using between 44 and 48% (w/w) CPOE. A m embrane with a general-purpose formulation is fully characterized and we sh ow calibration results for anionic surfactants such as dodecylbenzenesulfon ate (DBS-), tetrapropylenebenzenesulfonate and dodecylsulfate, or cationic surfactants such as Hyamine 1622 and cetyltrimethylammonium ion. With the p rimary ion DBS- we verified a 58.1 mV/dec sensitivity, a linear response be tween L x 10(-3) M and 3 x 10(-6) M, a detection limit corresponding to 0.2 6 ppm DBS- (7.9 x 10(-7) M) and a slope precision of 2.8 % RSD between days .