The Novel SCN - Ion-selective Electrode Based on the 1-Benzyl-3-(4-nitrophenyl) thio-urea Ionophore

A potentiometric sensor based on the 1-benzyl-3-(4-nitrophenyl) thio-urea was synthesized and tested as an ionophore in PVC based membrane sensor towards SCN− ions. This membrane exhibits a linear stable response over a wide concentration range (1.0 × 10−5 to 1.0 × 10−2 M) with a slope of −59.2 mV/dec., a detection limit of log[SCN−] = −5.05, and a selectivity coefficient for thiocyanate against perchlorate anion of = −0.133. The selectivity series of the membrane is as follows: SCN− > ClO4 − > I− > NO3 − > HSO3 − > Cl− > HSO4 − > F− > CH3COO− > HCO3 − > Br− > H2PO4 − > SO3 2− > SO4 2− > CO3 2−. The proposed electrode showed good selectivity and a good response for the SCN− ion over a wide variety of other anions in pH 6.0 buffer solutions and has a fast response time of about < 5s. The influences of the membrane by pH, ionophore, and plasticizer were studied. KCI Citation Count: 2