This research internship evaluates the effect of pH on the synthesis and deposition of AuNPs on CNTs and the relationship between the AuNPs deposited in the CNTs and their catalytic activity, considering that today only the influence of pH onto shape, size and distribution of AuNPs is known. This project has been executed with the idea that in the future woul be possible to use this nanomaterial CNT- AuNPs as transducer biosensors for the detection of polyphenols such as catechol . It was identified that the pH influences the particle size and affinity of nanotubes , affecting catalytic activity because the proportion of nanoparticles incorporated .