Highly selective oxalate-membrane electrode based on 2,2′-[1,4-butandiyle bis(nitrilo propylidine)]bis-1-naphtholato copper(II)

A new oxalate-selective electrode based on the complex 2,2′-[1,4-butandiyle bis(nitrilo propylidine)]bis-1-naphtholato copper(II) (CuL) as the membrane carrier was developed. The electrode exhibited a good Nernstian slope of −29.2 ± 0.6 mV/decade (mean value ± standard deviation, n = 5) and a linear range of 5.0 × 10−8 to 1.0 × 10−1 M for oxalate. The limit of detection was 5.0 × 10−8 M. This electrode represents a fast response time (i.e. 10–15 s) and could be used for more than 3 months. The selectivity coefficients were determined by the fixed interference method (FIM) and could be used in the pH range of 2.0–7.0. It was employed as an indicator electrode for the determination of oxalate in water samples.