title: Sensitive and selective colorimetric detection of Cu(2+) in aqueous medium via aggregation of thiomalic acid functionalized Ag nanoparticles.
abstract: A simple and effective colorimetric method for determination of Cu(2+) in real samples was developed. In this method, thiomalic acid functionalized silver nanoparticles (TMA-AgNPs) were prepared and changes in solution color, induced by the aggregation of TMA-AgNPs in the presence of Cu(2+), were employed for quantitative analysis. The surface plasmon resonance (SPR) band of our synthesized TMA-AgNPs was located at 392 nm and shifted to a longer wavelength after aggregation due to the interactions between carboxylate and Cu(2+). A band intensity ratio of A455/(A392-A455) was constructed and used to correlate with the concentration of Cu(2+). A linear relationship was found with a linear response up to 50 nM of Cu(2+). Due to the formation of a stable carboxylate Cu(2+) complex, highly sensitive detection of Cu(2+) was achieved with the estimated detection limit approaching 1 nM. Moreover, the formation of the stable complex leads to high selectivity in the detection of Cu(2+), which was verified by examination of 12 other metal ions. In the detection of Cu(2+) in real samples, results indicated that our proposed method is simple, sensitive and selective for application in such measurements.
authors.affiliation: Department of Chemistry, National Chung-Hsing University, 250 Kuo-Kuang Rd, Taichung 402, Taiwan. jyisy@dragon.nchu.edu.tw.
authors.forename: Vairaperumal
authors.initials: V
authors.lastname: Tharmaraj
authors.forename: Jyisy
authors.initials: J
authors.lastname: Yang
mesh_terms: D003124:Colorimetry / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*; D013870:Thiomalates / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D013870:Thiomalates; D014867:Water; D012834:Silver; C046062:2-thiomalic acid