Determination of heavy metal ions in mixed solution by imprinted SAMs

Specific selectivity toward different heavy metal ions could be introduced into self-assembled monolayers (SAMs) by ion imprinting. In the mixed solution, good response toward mercury ions could be obtained on mercury ions imprinted SAMs, the copper ions imprinted SAMs presented good selectivity toward copper ions, while on lead ions imprinted SAMs, significantly higher insertion of lead ions than mercury and copper ions were observed. Linear calibration plots were obtained for each heavy metal ion and the regression equations were: Ip/(10−6A)=−1.721+(−4.210) [Hg(II)]/(10−6M), Ip/(10−6A)=−1.438+(−1.420) [Cu(II)]/(10−6M) and Ip/(10−6A)=−3.779+(−3.551) [Pb(II)]/(10−6M) for mercury, copper and lead ions, respectively. The detection limits were determined to be: 1.46×10−8M for Hg(II), 3.73×10−8M for Cu(II) and 4.34×10−8M Pb(II). The decreases in current response for mercury, copper and lead ions in the presence of 100-fold interferential ions were: 3.37%, 9.16% and 7.60%, respectively. Acceptable recoveries were obtained in mixed solutions at both high and low concentrations.