Surface plasmon resonance analysis of aqueous copper ions with amino-terminated self-assembled monolayers

Surface plasmon resonance (SPR) can be used to selectively detect Cu2+ in the range of 0.1 μM to 1.0 mM with a reusable sensor surface, through appropriate pH control, using a relatively simple amino-terminated self-assembled monolayer (SAM) as a molecular recognition element. To detect Cu2+ ions in an aqueous solution using SPR, two types of SAMs, comprised of 2-aminoethane thiolhydrochloride (AET) and 6-aminohexane thiolhydrochloride (AHT), were used. Moreover the selectivity of two amino-terminated SAMs for Cu2+ ions, compared to Ni2+ and Zn2+, which are divalent and have similar ionic radii, was compared with SPR angle changes for each case.