Electronic Supplementary Material

A magnetized graphene oxide modified with 2-mercaptobenzothiazole as a selective nanosorbent for magnetic solid phase extraction of gold(III), palladium(II) and silver(I)

Mahmoud Reza Neyestani a,*, Farzaneh Shemirani b, Shahla Mozaffari c, Mahrouz Alvand d

a Department of Chemistry, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran

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

c Department of Chemistry, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran

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

Fig. S1:

a) Effect of sample pH on extraction efficiency. Extraction conditions: sample solution, 50 mL of 100 μg.L−1 of Au3+, Pd2+, and Ag+; 50 mg of mag-GO@MBT/SDS; 2.5 mL of 1 M thiourea in 0.01 M HNO3 as eluent; extraction time 15 min; desorption time, 5 min.

b) Effect of HNO3 Conc. on extraction efficiency. Extraction conditions: sample solution, 50 mL of 100 μg.L−1 of Au3+, Pd2+ and Ag+ at pH=4.0; 50 mg of mag-GO@MBT/SDS NPs; 2.5 mL eluent (0.75 M thiourea in various Conc. of HNO3); extraction time 15 min; desorption time 5 min.

c) Effect of thiourea Conc. on extraction efficiency. Extraction conditions: sample solution, 50 mL of 100 μg.L−1 of Au3+, Pd2+ and Ag+ at pH=4.0; 50 mg of mag-GO@MBT/SDS NPs; 2.5 mL eluent (various conc. of thiourea in 10 mM HNO3); extraction time 15 min; desorption time 5 min.

d) Effect of adsorbent amount on extraction efficiency. Extraction conditions: Sample solution, 50 mL of 100 μg.L−1 of Au3+, Pd2+ and Ag+, at pH=4.0; 2.5 mL of 0.75 M thiourea in 15 mM HNO3 as eluent; Extraction time, 15 min; Desorption time, 5 min.

e) Effect of sample Volume on extraction efficiency. Extraction conditions: Sample solution, various mL of 100 μg.L−1 of Au3+, Pd2+ and Ag+, at pH=4.0; 2.5 mL of 0.75 M thiourea in 15 mM HNO3 as eluent; 30 mg of Sorbent; Extraction time, 15 min; desorption time, 5 min.

f) Effect of extraction time on extraction efficiency. Extraction conditions: Sample solution, 50 mL of 100 μg.L−1 of Au3+, Pd2+ and Ag+, at pH=4.0; 2.5 mL of 0.75 M thiourea in 15 mM HNO3 as eluent; 30 mg of Sorbent; Various extraction times; Desorption time, 5 min.

Table S1: Tolerance limit of potentially interfering ions in extraction and determination of target metal ions
Au3+a / Pd2+a / Ag+a
Potentially
Interference Ions / Ratio ([Ion]/[Au+3]) / % Relative Recovery / Ratio ([Ion]/[Pd+2]) / % Relative Recovery / Ratio ([Ion]/[Ag+]) / % Relative Recovery
Na+ / 5000 / 99 / 5000 / 97 / 2500 / 101
K+ / 5000 / 97 / 5000 / 96 / 4000 / 103
Fe+3 / 2500 / 91 / 2500 / 96 / 2500 / 91
Mn+2 / 2500 / 93 / 2500 / 98 / 2500 / 92
Al+3 / 2500 / 94 / 2500 / 97 / 2500 / 91
Ca+2 / 5000 / 102 / 5000 / 95 / 5000 / 93
Mg+2 / 5000 / 96 / 5000 / 99 / 5000 / 102
Sr+2 / 2500 / 101 / 2500 / 97 / 2500 / 92
Ba+2 / 2500 / 98 / 2500 / 93 / 2500 / 90
Cu+2 / 250 / 91 / 250 / 92 / 500 / 90
Pb+2 / 1000 / 92 / 100 / 91 / 500 / 93
Zn+2 / 1000 / 95 / 1000 / 97 / 1000 / 94
Co+2 / 500 / 91 / 1000 / 95 / 500 / 92
Mo+2 / 500 / 94 / 1000 / 102 / 500 / 91
Ni+2 / 1000 / 95 / 500 / 97 / 1000 / 90
As+3 / 500 / 97 / 500 / 95 / 500 / 96
Cr+3 / 100 / 92 / 100 / 94 / 250 / 101
Sb+3 / 500 / 94 / 500 / 94 / 500 / 99
Cd+2 / 250 / 94 / 250 / 95 / 500 / 98
SO4-2 / 500 / 95 / 500 / 94 / 500 / 93
PO4-3 / 250 / 93 / 100 / 93 / 250 / 95
Cl- / 100 / 94 / 100 / 93 / 250 / 92
a concentration of target metal ion is 100 μg.L−1