The method includes inactivating {HEAD ~ endogenous enzyme activities} using {TAIL ~ neutral organic solvents} in conjunction with a matrix having minimal background noise  
using
The method includes inactivating { HEAD ~ endogenous enzyme activities } using { TAIL ~ neutral organic solvents } in conjunction with a matrix having minimal background noise
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH