Silver Nanoparticles for the Simultaneous Raman Detection of Anions, Cations and Neutral Molecules

摘要

Here we describe the possibility of using metal nanoparticles for the simultaneous detection of cations, anions and neutral molecules by means of surface-enhanced Raman spectroscopy (SERS) and surface-enhanced resonance Raman spectroscopy (SERRS). Silver nanoparticles were prepared by chemical reduction and their surfaces were modified either by treatment with positively or negatively charged coatings or by simply changing the aggregation agents. Non adsorbing SO_4~(2-) was used as an aggregating agent for the detection of anions. Each of the differently modified colloid/polymer mixtures can be deposited as a part of an array on planar silica substrates. In use, a small ( < μl) drop is applied to the array and the Raman spectra from each of the different clusters recorded simultaneously Since the individual signals from each cluster are spatially resolved, the spectra from each class of analyte can be detected separately. Using this approach it was possible to design and array which allowed anions and cations to be detected simultaneously on different tracks of the CCD detector.