N-Nortramadol/Creatinine:MRto:Pt:Urine:Qn:Confirm
n-nortramadol/creatinine:mrto:pt:urine:qn:confirm
N-nortramadol/Creatinine [Mass Ratio] in Urine by Confirmatory method
n-nortramadol/creatinine [mass ratio] in urine by confirmatory method