Preparation of PbS Nanoparticles by Phase-Transfer Method and Application to Pb²⁺-Selective Electrode Based on PVC Membrane

Figures & data

Figure 1 Structure of PbS-PVC membrane electrode: 1, sensitivity membrane; 2, PVC tube; 3, Ag/AgCl coated wire internal reference electrode; 4, internal solution; 5, electrode base; and 6, electrode wire.

Figure 2 TEM image of PbS nanoparticles.

Figure 3 UV-vis spectrum of PbS nanoparticles: 1, H₂D_z/CCl₄; 2, Pb²⁺–H₂D_z/CCl₄; 3, PbS nanoparticles.

Figure 4 Variation of UV-vis spectrum with different acidity of Pb²⁺ ion solution: a = 4; b = 5; c = 6; d = 7; e = 8; f = 9; and g = 10.

Figure 5 Influence of the ratio between H₂D_z and CCl₄: a = 1:1; b = 1:1.5; c = 1:2; and d = 1:2.5.

Figure 6 Influence of the potential response of Pb²⁺ selective electrode with different internal filling solution: a, 1 × 10⁻² mol · L⁻¹; b, 5 × 10⁻² mol · L⁻¹; and c, 1 × 10⁻¹ mol · L⁻¹.

Figure 7 Variation of the potential of PVC membrane with different volume of PbS nanoparticles: a, 10 mL; b, 20 mL; c, 30 mL; d, 40 mL; and e, 50 mL.

Figure 8 Effect of pH on cell potential of sensors at Pb²⁺ activity of 1.0 × 10^–3 mol · L⁻¹.

Table 1. Selectivity coefficients () obtained in the presence of various interfering ions for the lead electrode

Interfering ion
K^+	7.2 × 10^−1
Na^+	6.7 × 10^−1
Cu^2+	9.94 × 10^−2
Ca^2+	1.25 × 10^−2
Ba^2+	1.31 × 10^−2
Ni^2+	1.17 × 10^−2
Al^3+	5.25 × 10^−3

Figure 9 The response to some cations of Pb²⁺ selective electrode based on PbS nanoparticles: 1, Pb²⁺; 2, Na⁺; 3, K⁺; 4, Ca²⁺; 5, Ba²⁺; 6, Cu²⁺; 7, Al³⁺; and 8, Ni²⁺.

Figure 10 Potentiometric titration plot of 1.0 × 10⁻⁴ mol · L⁻¹ Pb²⁺ solution (25 mL) with 1.0 × 10⁻³ mol · L⁻¹ EDTA solution.