Preconcentration of Trace Cadmium Ion Using Magnetic Graphene Nanoparticles As Anefficient

Electronic Supplementary Material

Preconcentration of trace cadmium ion using magnetic graphene nanoparticles as anefficient adsorbent

MahrouzAlvand, Farzaneh Shemirani

Department of Analytical Chemistry, University College of Science, University of Tehran, Tehran, Iran P.O. Box 14155-6455, Tehran, Iran

*Corresponding author: E-mail: , Tel: +98 21 61112481, Fax: +98 21 66405141

Fig.S1 Infrared spectra of GO (a) and G-Fe3O4 nanocomposite (b).

Fig S1 shows the FT-IR spectrums of GO (a) and G-Fe3O4 (b). In the FT-IR spectrum of GO (Fig. S1a) we observe a strong and broad absorption at 3378 cm-1due to O–H stretching vibration. The C=O stretchingof COOH groups situated at GO surface is observed at1706cm-1. The absorptions due to the O–H bending vibration,epoxide groups and skeletal ring vibrations are observed around1614cm-1 and C–O stretching (1036 cm−1). In Fig. S1bthe absorption of G-Fe3O4 nanocomposite at 584 cm−1was ascribed to (Fe–O). The IR spectrum in Fig. S1b conﬁrms reduction ofGO sheets. Here the absorption due to the C=O group (1706cm-1)is absent and absorptions at 1614 and1036cm-1are decreased very much in intensity, suggesting the considerable reduction by by Fe2+ ions in the fabrication ofG-Fe3O4.

Fig. S2 Effect of PAN concentration on the recovery of Cd(II). Conditions:Amount of metal ions: 50 μg L– 1 Cd(II), pH = 6.0, sample volume 50 mL, amount of sorbent: 50 mg, eluent (HNO3) concentration: 1.0 mol L– 1, eluent volume: 1.5 mL.

Fig. S3 Effect of sample volume on the recovery of Cd(II)Amount of metal ions: 2.5 μg Cd(II ), 8 × 10– 6 mol L– 1 of PAN, pH = 6.0, sample volume 50 mL, amount of sorbent: 50 mg, eluent (HNO3) concentration: 1.0 mol L– 1, eluent volume: 1.5 mL.

Effects of coexisting ions

Extraction experiments for series of solution containing 2.5 µg of other metal ions were carried out according to the developed MSPE method.The results (Fig. S4) showed that the extraction recoveries of these ions were not quantitative. In view of the high selectivity provided by FAAS and the excess amount of ligand that was used during the described procedure, presence of other heavy metal ions cannot interfere with cadmium determination.

Fig. S4The recoveries of other metal ions.Conditions: Amount of metal ions: 2.5 μg of each metal ions, 8 × 10– 6 mol L– 1 of PAN, pH = 6.0, sample volume 50 mL, amount of sorbent: 50 mg, eluent (HNO3) concentration: 1.0 mol L– 1, eluent volume: 1.5 mL.