Determination of copper in black, red pepper and the waste water samples by a highly selective sensitive Cu(II) microelectrode based on a new hexadentates Schiff's base

Abstract

A Cu2+ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff's base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl) ethylidene] hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of 1.0 × 10-5-1.0 × 10-11 M of Cu2+. The microelectrode exhibits a nice Nernstian slope of 25.9 ± 0.3 mV decade-1 in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges (∼5 s). The detection limit of proposed sensor is 5.0 × 10-12 M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Cu2+ with EDTA. The proposed membrane electrode was used for the direct determining of Cu2+ content in black and red pepper, and in waste water samples.