A Novel Iron(III)-Selective Membrane Potentiometric Sensor Based on 5-Chloro-3-[4-(trifluoromethoxy) phenylimino] Indolin-2-one (original) (raw)

A novel polyvinyl chloride (PVC) membrane sensor that is highly selective to Fe 3+ ions was prepared by using 5-chloro-3-[4-(trifluoromethoxy)phenylimino]indolin-2-one (CFMEPI) ionophore. The sensor exhibits a Nernstian response for Fe 3+ ions over a wide concentration range (1.0 ×10 -2 −1.0×10 -6 M) with a slope of 46.7±0.5 mV per decade. The sensor has a response time of 20s and can be used for at least 3 months without any measurable divergence in potential. It was concluded that the sensor response was pH independent in the range of 4.0-8.61. The sensor has some advantages such as short analysis time, particularly high selectivity towards iron (III). The sensor was used successfully for direct determination of Fe 3+ in several synthetic and real samples with satisfactory results.