Identification of Nanoparticles with a Colorimetric Sensor Array

A simple colorimetric sensor array technique was developed for the detection of various different nanoparticles (NPs) in aqueous solutions. The sensor array consists of five different cross-reactive chemoresponsive dyes, whose visible absorbances change in response to their interactions with NPs. Although no single dye is specific for any one NP, the pattern of color changes for all dyes provides a unique molecular fingerprint for each type of NP studied. Based on the responses of various dyes, a semiquantitative determination of concentration of each type of NP could also be accomplished with excellent sensitivity (