Development and application of a novel lead ion-selective electrode with the alkylamines modified molecular sieve as carrier.

The molecular sieve HZSM-5A was modified by incorporation of two alkylamines (C8H17-CH = NH, C10H21-CH = NH; loading materials) and such two surfactant modified zeolites (SMZs), SMZ-C8 and SMZ-C10, were served as the active substance in lead ion-selective electrode (ISE). Optimization of the polyvinyl chloride (PVC)-based membrane electrodes was obtained for a membrane composition of 30% PVC, 65% dioctyl phthalate (DOP) and 5% (w/w) carrier. The ISEs exhibited Nernstian slopes of 25.9 ± 0.3 and 28.6 ± 0.3 mV/decade for Pb2+ with the detection limits of 5.89 (± 0.12) × 10–7 M and 6.08 (± 0.16) × 10–9 M in the concentration of 1.0 × 10–2 to 1.0 × 10–6 M and 1.0 × 10–3 to 1.0 × 10–8 M, respectively. The lifetime of the electrodes was found at least 8 weeks and their response time was less than 10 s. The ISEs did not suffer interference from most metal cations and were successfully used as indicator electrodes for potentiometric titration of Pb2+ with K2CrO4 and for determinations of Pb2+ in an alcoholic beverage and tea leaves samples. [ABSTRACT FROM AUTHOR]