JOURNAL OF ANALYTICAL CHEMISTRY, cilt.60, sa.12, ss.1139-1143, 2005 (SCI-Expanded)
Hydrogels based on N,N-dimethylacrylamide (DMAAm), allylthiourea (ATU), and maleic acid (MA) were synthesized by free-radical cross-linking copolymerization in water with N,N-methylene-bis(acrylamide) (BAAm) as the cross-linker, ammonium persulfate (APS) as the initiator, and N,N,N',N'-tetramethyl-enediamine (TEMED) as the activator. Since Se(IV) is the most serious interfering element in the electroanalytical (polarographic or voltammetric) determination of lead and cadmium, a new method for their correct determination after selective separation of the interfering ion (selenite) was developed by using poly(N,N-dimethylacrylamide-co-allylthiourea) [P(DMAAm-co-ATU)] hydrogels containing reducing pedant groups like allylthiourea. The proposed method showed good reproducibility and accuracy with relative standard deviations of 8.5 and 3.4% and relative errors of -6.0 and -5.4% for the determination of 5.0 x 10(-5) M Pb(II) and Cd(II), respectively, next to 3.0 x 10(-5) M Se(IV).