In a preferred embodiment, {HEAD ~ R} is an acyl group wherein R1 is methyl such that the labeled compounds are methanol , {TAIL ~ acetates} wherein said 13C atom is directly bonded to exactly one or two deuterium atoms 
In a preferred embodiment , { HEAD ~ R } is an acyl group wherein R1 is methyl such that the labeled compounds are methanol , { TAIL ~ acetates } wherein said 13C atom is directly bonded to exactly one or two deuterium atoms
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH