The water-soluble 3-n-propyl-4-picolinium silsesquioxane chloride (Si4Pic(+)Cl(-)) polymer was prepared, characterized and used as a stabilizing agent for the synthesis of gold nanoparticles (nAu). The ability of Si4Pic(+)Cl(-) to adsorb anionic metal complexes such as AuCl4- ions allowed well-dispersed nAu to be obtained with an average particle size of 4.5nm. The liquid suspension of nAu-Si4Pic(+)Cl(-) was deposited by the drop coating method onto a glassy carbon electrode (GCE) surface to build a sensor (nAu-Si4Pic(+)Cl(-)/GCE) which was used for the detection of o-nitrophenol (o-NP) and p-nitrophenol (p-NP). Under optimized experimental conditions the reduction peak current increased with increasing concentrations of both nitrophenol isomers in the range of 0.1-1.5 mu mol L-1. The detection limits were 46 nmol L-1 and 55 nmol L-1 for o-NP and p-NP, respectively. These findings indicate that the nAu-Si4Pic(+)Cl(-) material is a very promising candidate to assemble electrochemical sensors for practical applications in the field of analytical chemistry. (C) 2014 Elsevier B.V. All rights reserved.