Melanin-Based Coatings as Lead-Binding Agents

Table 2

Percentage of Pb²⁺ bound at equilibrium.

Initial [Pb^2+]	Synthetic eumelanin^a			Hair extract^a
	pH 5.50	pH 4.75	pH 4.00	pH 5.50	pH 4.75	pH 4.00
15.1 μM	>95%	>95%	>95%	82.2%	68.2%	42.6%
30.2 μM	>95%	>95%	73.3%	58.6%	49.7%	29.4%
60.4 μM	68.8%	68.7%	52.6%	41.2%	36.1%	22.5%
105.7 μM	49.8%	46.7%	38.7%	32.1%	26.7%	16.7%
151.0 μM	39.3%	36.8%	29.4%	26.9%	21.0%	14.9%
302.0 μM	22.4%	21.0%	18.3%	16.1%	14.1%	10.0%
604.0 μM	12.4%	11.8%	10.6%	10.8%	8.8%	6.3%
1057.0 μM	8.0%	7.6%	6.7%	7.2%	5.7%	4.9%
1510.0 μM	5.6%	5.6%	5.2%	5.6%	4.8%	4.3%
2265.0 μM	4.0%	4.0%	3.6%	4.2%	3.4%	3.2%

^aPercentage of Pb²⁺ bound at equilibrium for each initial concentration from the titrations shown in Figures 2(c) and 2(d).