Application of poly(cyclophosphazene) for potentiometric detection of tributyl phosphate vapor

Potentiometric sensing layer for detection of tributyl phosphate (TBP) in the concentration range from 1.1 ppb up to 8.8 ppm is described. The high sensitivity to TBP is based on a specific charge-transfer interaction that occurs between iodine species and the oxygen atom of the phosphoryl group of TBP. Thr iodine is incorporated electrochemically or chemically into a chemically inert poly(cyclophosphazene-benzoquinone), PPBQ, matrix. The bulk involvement of the new material in the interaction with the TBP vapor leads to modulation of its Fermi level. The number of moles of charge shared bq the TBP with the sensitive layer is between 0.8 to 0.9 in the range of concentrations between 0.27 and 8.8 ppm. The interaction is highly reversible and reproducible.