Parameter Reagent I II III IV lmax   462 478 482 495 Beer’s law, mg mL−1 0.05-1.20 0.05-1.00 0.5-1.10 0.05-1.15 Ringbom conc, mg mL−1 0.15-1.05 0.20-0.85 0.1-1.0 0.15-1.05 Molar absorptivity, L mol-1cm−1 1.05 x 105 1.12 x 105 1.57 x 105 1.31 x 105 Sandell sensitivity ng cm−2 1.97 1.85 1.32 1.58 Detection limit, ng mL-1 15 14 16 17 Quantification limit, ng mL-1 48 45 50 54 Stability up to bray 7.0 7.0 9.0 10.6 Regression equation *         (a) intercept - 0.013 0.009 0.012 - 0.008 (b) slope 0.51 0.54 0.76 0.63 Correlation coefficient a 0.9992 0.9990 0.9996 0.9988 Standard deviation % 0.38 0.61 0.72 0.54  Relative standard deviation % 0.87 1.13 1.27 0.96 Error % ± 1.3 ± 1.6 ± 1.7 ± 1.5 aA = a +bC where C is the concentration of Pb2+ in ng mL−1

Table 4: Physical and analytical parameter for Pb - complexed with polyester I-IV.