Nitrate-Selective Membrane Electrode Based on Bis(2-hydroxyanil)acetylacetone Lead(II) Neutral Carrier

摘要

A nitrate-selective electrode based on a recently synthesized bis(2-hydroxyanil)acetylacetone lead(II) complex [(haacac)Pb] has been developed. Among different compositions studied, a membrane containing 30.7% poly(vinyl chloride) (PVC), 61.3% dibutyl phthalate (DBP) as a plasticizer, 3% methyltrioctylammonium chloride (MTOAC) as a cationic additive and 5% ionophore (all w/w) exhibited the best potentiometric response toward nitrate ion in aqueous solutions. The potentiometric response of the electrode was linear with a Nernstian slope of -58.8 mV decade-1 within the NO3- concentration range of 2 × 10-5 - 1 × 10-1 mol dm-3. The response time of the electrode was ≤ 10 s over the entire linear concentration range of the calibration plot. The electrode is suitable for use within the pH range of 5.3 - 11. The selectivity coefficients for the proposed electrode were improved for some interferences, when compared with those of commercially available nitrate-selective electrodes.