Synthesis of para-sulfonatocalix[4] arene-modified silver nanoparticles as colorimetric histidine probes

This Communication reports a novel colorimetric sensor to probe histidine in water based on para-sulfonatocalix[4]arene modified silver nanoparticles; this highly selective sensor allows a rapid quantitative assay of histidine down to a concentration of 5 x 10(-6) M, providing a new tool for the direct measurement of histidine.