loop_
                _sas_sample_entities.id
                _sas_sample_entities.sample_id
                _sas_sample_entities.entity_id
                _sas_sample_entities.concentration
                 1 1 BSA 1.2
                 2 1 LYZ 0.7
                 3 2 BSA 3.3
                 3 2 HGF .
                 3 2 EPO 0.1