The 24-year old Chile international has had mixed season at the Camp Nou and the Catalans are willing to listen to offers at the end of the season.
Arsenal are monitoring the situation with other targets Stevan Jovetic from Fiorentina and Pierre-Emerick Aubameyang of Saint-Etienne but after losing out to sign David Villa, who is likely to be offered a new deal by Barcelona, the Gunners feel the Chilean can be the right man to steer the club forward.
Sanchez snubbed offers from Premier League clubs to join Barcelona from Udinese for £22million in 2011.
The Gunners are also preparing to smash the clubs transfer record fee to sign Jovetic from Fiorentina in the summer. Arsene Wenger is ready to spend £20million for the Montenegro international.
Arsenal's previous highest transfer fee was £15million for Andrey Asharvin from Zenit St Petersburg, but the Russian is likely to leave the Emirate at the end of the season.
Jovetic, 23, has been watched by Arsenal scouts from the beginning of the season and are certainly moving ahead with a bid at the end of the season.
Meanwhile, Liverpool and Juventus have also shown interest to sign Sanchez. The Chile international has made 34 appearances scoring just 5 goals in all competition this season and has been out of favour for striker David Villa.
Since joining Barca in 2011, Sanchez has scored 20 goals in 75 appearances.