Determination of Metals in Natural Waters by Inductively Coupled Plasma Optical Emission Spectroscopy after Preconcentration on Silica Sequentially Coated with Layers of Polyhexamethylene Guanidinium and Sulphonated Nitrosonaphthols

Table 2

Desorption degree () NRS, NKS, and NNS from the surface of SiO₂-PHMG by washing with 10 mL of NaCl solution (mass of adsorbents 0.1 g, reagents content 40 µMg⁻¹, n = 5, P = 0.95).

, M	, %
	NRS	NKS	NNS
0.05	1.5	1.0	6
0.1	12	13	17
0.25	15	15	20
0.5	18	19	27
1.5	56	55	61