Highly sensitive label-free colorimetric sensing of nitrite based on etching of gold nanorods

A simple colorimetric method with high sensitivity and selectivity was developed for sensing of nitrite as low as 4.0 mu M by naked eyes, which is based on etching of gold nanorods accompanied by shape changes in aspect ratios (length/width) and a visible color change from bluish green to red and then to colorless with the increase of nitrite.