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 5

Elution (%) of metal ions adsorbed on SiO₂-PHMG-NRS and SiO₂-PHMG-NNS with nitric acid solutions (eluent volume is 10 mL).

Metal	SiO2-PHMG-NRS			SiO2-PHMG-NNS
	0.1М HNO3	1М HNO3	2М HNO3	0.1М HNO3	1М HNO3	2М HNO3
Cu(II)	50.3	99.5	99.8	65.2	99.4	99.9
Fe(III)	30.8	99.5	99.9	37.5	99.7	99.8
Co(II)	-	8.5	12.0	-	8.3	10.7
Al(III)	78.5	99.9	99.9	85.9	99.6	99.8
Ni(II)	68.2	99.3	99.9	70.4	99.8	99.9
Zn(II)	83.4	99.9	99.8	89.4	99.8	99.8
Pb(II)	88.8	99.2	99.5	90.6	99.5	99.5