Gallium(III) selective sensors based on 2-amino-3-(α-N-phenylmethyl-2′-amino-1′,4′-naphthoquinonyl)-1,4 naphthoquinones in poly (vinyl chloride)

Synthesis and application of 2-amino-3-(α-N-phenylmethyl-2′-amino-1′,4′-naphthoquinonyl)-1,4 naphthoquinone (S) as a neutral ionophore for the determination of gallium(III) in PVC-based membrane sensors has been described. The sensor based on membrane composition (w/w, mg%); 5.0 (S):30.0 (PVC):5.0 (KTpClPB):60.0 (o-NPOE) is the best and showed a working range of 2.3 × 10−7 to 1.0 × 10−2 M with detection limit of 1.2 × 10−7 M. It can tolerate non-aqueous media up to 15% with a slope of 19.7 mV decade−1 of activity. The sensor has been used to assess the Ga(III) concentration in different natural samples (peach and tomato leaves, coal-fly-ash and river sediments). It can be used for 2.5 months without any distortion in results, after which, leaching of ionophore was observed from the membrane phase. The proposed sensor has shown a good dynamic response time of 11 s.