The invention relates to a process involving analyzing the presence of arsenic in a sample, comprising the following steps: (a) contacting a sample suspected of containing arsenic on a solid support functionalized with a DNA fragment comprising an ArsR protein binding site, site on which an ArsR protein is attached, the presence arsenic causing separation of the ArsR protein from the DNA fragment; (b) incubation of the sample in contact with the said support; (c) elimination of ArsR protein separated from the DNA fragment by washing the support after the incubation carried out in step (b); and (d) analyzing by an ELISA technique to detect the presence or absence of ArsR protein remaining attached to the DNA fragment.