SERS Surfaces Modified with a 4-(2-Pyridylazo)resorcinol Disulfide Derivative: Detection of Copper, Lead, and Cadmium
作者:L. Gayle. Crane、DaoXin. Wang、L. Malia. Sears、Bernard. Heyns、Keith. Carron
DOI:10.1021/ac00098a021
日期:1995.1.15
We have developed a surface-enhanced Raman spectroscopic technique for the determination of Ph(2+), Cd2+, and Cu2+ concentration using a 4-(2-pyridylazo)resorcinol (PAR) coating modified with a disulfide. The disulfide provided a strong anchor to a roughened sih er substrate. Atomic specificity was demonstrated by the distinct spectral changes that occurred through the interaction of Pb2+, Cd2+, and Cu2+ ions with the indicator. The absorption of these metals by the coating was followed with SERS and could be fit to a Frumkin isotherm. Langmuirian behavior was not observed; this is most likely due to the electrostatic repulsions as the metal cations are absorbed. The detection limits at pH 6 for Pb2+, Cd2+, and Cu2+ were 522, 50.3, and 1.49 ppb, respectively. Flow experiments using an optical fiber probe indicated instantaneous response to changes in metal concentration.