A Sensitive Impedimetric Sensor Based on Biosourced Polyphosphine Films for the Detection of Lead Ions

Abstract

In this work, impedimetric sensors were developed for the detection of the four WFD heavy metals Pb2+, Cd2+, Hg2+ and Ni2+, by the modification of a gold electrode with four partially biosourced polyphosphine polymers. These polymers were obtained with satisfactory yields by polycondensation of the bis(4-fluorophenyl)(4-methylphenyl)phosphine sulfide and the bis(4-fluorophenyl)(4-methylphenyl)phosphine oxide using isosorbide or bisphenol A. The chemical structures and number-average molecular weights of the resulting polymers were determined by NMR spectroscopy (1H, 19F, and 31P) and by size exclusion chromatography. Glass transition temperatures varied between 184 and 202 °C depending on the composition of polymers. The bio-based poly(etherphosphine) oxide modified sensor showed better analytical performance than petrochemical based oxide for the detection of Pb2+. A detection limit of 10−10 g/L or 0.5 pM, which is 104 times lower than that of the anodic stripping voltammetric and the potentiometric sensors. A reversibility is obtained through rinsing of the impedimetric sensor with an EDTA solution.