GRO retention time marker

Pholcodine monohydrate,neat,neat,100mg,

2-Nitrophenol, 1000µg/mL, Solvent-toluene, Unit 1mL, # of units-1, Cas.no. 88-75-5

Metronidazole,1000 µg/mL,MeOH,1mL,