Simplify reaction monitoring over time with instant feedback. Here we compare LC/MS data showing the relative concentration of the precursor and product over time vs. results obtained without the LC separation using DART. The distribution of ions in the DART mass spectrum is observed to be similar to the distribution observed using the LC/MS UV detector. The cumulative time for the DART experiments is under 30 seconds, while each LC/MS analysis requires 5 minutes for analysis.