you should descript in detail, or give literature.Otherwise it's easy to mistake it for the same material

I don't think both are same. Principally, local maximum UV peak for GO is at 232 nm while for graphene with oxygen groups is at 271 nm due to the difference in excitation transition. For GO, the formation of local maximum is caused by transition of sigma  to sigma* molecules. In contrast to GO, graphene with oxygen group has intact basal structure and thus is resulting in the excitation transition of pie molecules to pie* and therefore local peak at 271 nm like pristine graphene. The difference between GO and graphene with oxygen group is more clear from the XPS characterisation of graphene product.