Water Soluble Cationic Porphyrin Sensor for Detection of Hg²⁺, Pb²⁺, Cd²⁺, and Cu²⁺

Figure 4

The electronic absorption spectra of aqueous solution of 1 (5.0 × 10⁻⁶ M) upon addition of increasing amount 0, 1665, 0.333, 0.4995, 0.666, 0.8325, 0.999, 1.1655, 1.332, 1.4985, 1.665, 1.8315, 1.998, 2.1645, 2.331, 2.4975, 2.664, 2.8305, 2.997, 3.1635, 3.33, 3.4965, 3.663, 3.8295, 3.996, 4.1625, 4.329, 4.4955, 4.662, 4.8285, 4.995, 5.8275, 6.66, 7.4925, 8.325, and 9.15 (×10⁻⁷ M) of Hg²⁺, Pb²⁺, and Cd²⁺ ions.