A comparative study on PVC based sensors in determination of molybdenum

The proposed work described the synthesis of neutral ionophores; 4,8-diaza-3,3,10,10-tetramethyl-1,2-dithiacyclodecane (S-1), 5,8-diaza-3,3,10,10-tetramethyl-1,2 dithiacyclodecane-N,N ''-diacetic acid (S-2) and N,N ''-bis(2,2-dimethyl-2-mercaptoethyl)ethylenediamine-N,N-diacetic acid (S-3) used for comparative analysis in determination of molybdenum(v) as PVC-based membrane sensors. The best result was obtained with sensor no. 7 based on S-3 ionophore with membrane composition (w/w, mg%); 5.0(S) : 30.0(PVC) : 5.0(KTpCIPB) : 60.0(o-NPOE) showing a working range of 2.3 x 10(-7)-1.0 x 10(-2) M with a detection limit of 1.2 x 10(-7) M and a toleration of non-aqueous media up to 15% with slope of 11.7 mV/decade of activity. The sensor no. 7 can also be used to assess the Mo(v) concentration in different natural samples (water bodies, soils, root nodules and urine samples) with comparative analysis of ETAAS and spectrophotometric methods. The proposed sensor no. 7 can be used 2.5 months without any distortion in results after that leaching of ionophore was observed from the membrane phase in aqueous solutions of Mo(v). The proposed sensor has shown a good dynamic response time of 11 s.