Novel poly(ethylene glycol)s bearing tributyltin carboxylate end groups as ionophores in the development of chloride ion-selective electrodes

摘要

The potentiometric response characteristics of electrodes based on PVC membranes containing novel polyethylene glycols (PEGs) with tributyltin carboxylate end groups as ionophores for chloride ions were studied in 0.1 M HEPES solution, at the spontaneous pH. The effects of solvent mediator, amount of cationic additive, amount of ionophore and PEG chain length on the behavior of the sensors were investigated. The membranes with the best composition responded to chloride concentration in a linear range from 10(-4) to 10(-1) M Cl- with a nearly Nernstian slope and a detection limit of 6.5 x 10(-5) M. The sensor showed a short response time (< 25 s) in the whole concentration range and an operational lifetime of about one week for the most performing PVC membranes. In comparison with ISEs based on anion exchangers the interferences from the more lipophilic anions were greatly reduced, as inferable by the selectivity coefficients determined with the matched potential method at chloride concentration of 3.0 x 10(-3) M.