No, Gohan is not a pure-blood Saiyan.
Gohan is the son of Goku (a pure-blood Saiyan) and Chi-Chi (a human). This makes him a hybrid Saiyan, often referred to as a half-Saiyan or part-Saiyan. The reference provided even states that Gohan is half-Saiyan.
Pure-blood Saiyans are those born to two Saiyan parents on Planet Vegeta (or elsewhere, as long as both parents are fully Saiyan). Because Gohan has a human mother, he cannot be considered a pure-blood Saiyan.
